This post is courtesy of Otavio Ferreira, Manager, Amazon SNS, AWS Messaging.
Amazon SNS message filtering provides a set of string and numeric matching operators that allow each subscription to receive only the messages of interest. Hence, SNS message filtering can simplify your pub/sub messaging architecture by offloading the message filtering logic from your subscriber systems, as well as the message routing logic from your publisher systems.
After you set the subscription attribute that defines a filter policy, the subscribing endpoint receives only the messages that carry attributes matching this filter policy. Other messages published to the topic are filtered out for this subscription. In this way, the native integration between SNS and Amazon CloudWatch provides visibility into the number of messages delivered, as well as the number of messages filtered out.
The following six CloudWatch metrics are relevant to understanding your SNS message filtering activity:
NumberOfMessagesPublished – Inbound traffic to SNS. This metric tracks all the messages that have been published to the topic.
NumberOfNotificationsDelivered – Outbound traffic from SNS. This metric tracks all the messages that have been successfully delivered to endpoints subscribed to the topic. A delivery takes place either when the incoming message attributes match a subscription filter policy, or when the subscription has no filter policy at all, which results in a catch-all behavior.
NumberOfNotificationsFilteredOut – This metric tracks all the messages that were filtered out because they carried attributes that didn’t match the subscription filter policy.
NumberOfNotificationsFilteredOut-NoMessageAttributes – This metric tracks all the messages that were filtered out because they didn’t carry any attributes at all and, consequently, didn’t match the subscription filter policy.
NumberOfNotificationsFilteredOut-InvalidAttributes – This metric keeps track of messages that were filtered out because they carried invalid or malformed attributes and, thus, didn’t match the subscription filter policy.
NumberOfNotificationsFailed – This last metric tracks all the messages that failed to be delivered to subscribing endpoints, regardless of whether a filter policy had been set for the endpoint. This metric is emitted after the message delivery retry policy is exhausted, and SNS stops attempting to deliver the message. At that moment, the subscribing endpoint is likely no longer reachable. For example, the subscribing SQS queue or Lambda function has been deleted by its owner. You may want to closely monitor this metric to address message delivery issues quickly.
Message filtering graphs
Through the AWS Management Console, you can compose graphs to display your SNS message filtering activity. The graph shows the number of messages published, delivered, and filtered out within the timeframe you specify (1h, 3h, 12h, 1d, 3d, 1w, or custom).
To compose an SNS message filtering graph with CloudWatch:
Open the CloudWatch console.
Choose Metrics, SNS, All Metrics, and Topic Metrics.
Select all metrics to add to the graph, such as:
Choose Graphed metrics.
In the Statistic column, switch from Average to Sum.
Title your graph with a descriptive name, such as “SNS Message Filtering”
After you have your graph set up, you may want to copy the graph link for bookmarking, emailing, or sharing with co-workers. You may also want to add your graph to a CloudWatch dashboard for easy access in the future. Both actions are available to you on the Actions menu, which is found above the graph.
SNS message filtering defines how SNS topics behave in terms of message delivery. By using CloudWatch metrics, you gain visibility into the number of messages published, delivered, and filtered out. This enables you to validate the operation of filter policies and more easily troubleshoot during development phases.
SNS message filtering can be implemented easily with existing AWS SDKs by applying message and subscription attributes across all SNS supported protocols (Amazon SQS, AWS Lambda, HTTP, SMS, email, and mobile push). CloudWatch metrics for SNS message filtering is available now, in all AWS Regions.
It’s a public holiday here today (yes, again). So, while we indulge in the traditional pastime of barbecuing stuff (ourselves, mainly), here’s a little trove of Pi projects that cater for our various furry friends.
Nicole Horward created Project Floofball for her hamster, Harold. It’s an IoT hamster wheel that uses a Raspberry Pi and a magnetic door sensor to log how far Harold runs.
JaganK3 used to work long hours that meant he couldn’t be there to feed his dog on time. He found that he couldn’t buy an automated feeder in India without paying a lot to import one, so he made one himself. It uses a Raspberry Pi to control a motor that turns a dispensing valve in a hopper full of dry food, giving his dog a portion of food at set times.
He also added a web cam for live video streaming, because he could. Find out more in JaganK3’s Instructable for his pet feeder.
Shark laser cat toy
Sam Storino, meanwhile, is using a Raspberry Pi to control a laser-pointer cat toy with a goshdarned SHARK (which is kind of what I’d expect from the guy who made the steampunk-looking cat feeder a few weeks ago). The idea is to keep his cats interested and active within the confines of a compact city apartment.
All of these makers are generous in acknowledging the tutorials and build logs that helped them with their projects. It’s lovely to see the Raspberry Pi and maker community working like this, and I bet their projects will inspire others too.
Now, if you’ll excuse me. I’m late for a barbecue.
Thanks to Susan Ferrell, Senior Technical Writer, for a great blog post on how to use CodeCommit branch-level permissions. —-
AWS CodeCommit users have been asking for a way to restrict commits to some repository branches to just a few people. In this blog post, we’re going to show you how to do that by creating and applying a conditional policy, an AWS Identity and Access Management (IAM) policy that contains a context key.
Why would I do this?
When you create a branch in an AWS CodeCommit repository, the branch is available, by default, to all repository users. Here are some scenarios in which refining access might help you:
You maintain a branch in a repository for production-ready code, and you don’t want to allow changes to this branch except from a select group of people.
You want to limit the number of people who can make changes to the default branch in a repository.
You want to ensure that pull requests cannot be merged to a branch except by an approved group of developers.
We’ll show you how to create a policy in IAM that prevents users from pushing commits to and merging pull requests to a branch named master. You’ll attach that policy to one group or role in IAM, and then test how users in that group are affected when that policy is applied. We’ll explain how it works, so you can create custom policies for your repositories.
What you need to get started
You’ll need to sign in to AWS with sufficient permissions to:
Create and apply policies in IAM.
Create groups in IAM.
Add users to those groups.
Apply policies to those groups.
You can use existing IAM groups, but because you’re going to be changing permissions, you might want to first test this out on groups and users you’ve created specifically for this purpose.
You’ll need a repository in AWS CodeCommit with at least two branches: master and test-branch. For information about how to create repositories, see Create a Repository. For information about how to create branches, see Create a Branch. In this blog post, we’ve named the repository MyDemoRepo. You can use an existing repository with branches of another name, if you prefer.
Let’s get started!
Create two groups in IAM
We’re going to set up two groups in IAM: Developers and Senior_Developers. To start, both groups will have the same managed policy, AWSCodeCommitPowerUsers, applied. Users in each group will have exactly the same permissions to perform actions in IAM.
Figure 1: Two example groups in IAM, with distinct users but the same managed policy applied to each group
In the navigation pane, choose Groups, and then choose Create New Group.
In the Group Name box, type Developers, and then choose Next Step.
In the list of policies, select the check box for AWSCodeCommitPowerUsers, then choose Next Step.
Choose Create Group.
Now, follow these steps to create the Senior_Developers group and attach the AWSCodeCommitPowerUsers managed policy. You now have two empty groups with the same policy attached.
Create users in IAM
Next, add at least one unique user to each group. You can use existing IAM users, but because you’ll be affecting their access to AWS CodeCommit, you might want to create two users just for testing purposes. Let’s go ahead and create Arnav and Mary.
In the navigation pane, choose Users, and then choose Add user.
For the new user, type Arnav_Desai.
Choose Add another user, and then type Mary_Major.
Select the type of access (programmatic access, access to the AWS Management Console, or both). In this blog post, we’ll be testing everything from the console, but if you want to test AWS CodeCommit using the AWS CLI, make sure you include programmatic access and console access.
For Console password type, choose Custom password. Each user is assigned the password that you type in the box. Write these down so you don’t forget them. You’ll need to sign in to the console using each of these accounts.
Choose Next: Permissions.
On the Set permissions page, choose Add user to group. Add Arnav to the Developers group. Add Mary to the Senior_Developers group.
Choose Next: Review to see all of the choices you made up to this point. When you are ready to proceed, choose Create user.
Sign in as Arnav, and then follow these steps to go to the master branch and add a file. Then sign in as Mary and follow the same steps.
On the Dashboard page, from the list of repositories, choose MyDemoRepo.
In the Code view, choose the branch named master.
Choose Add file, and then choose Create file. Type some text or code in the editor.
Provide information to other users about who added this file to the repository and why.
In Author name, type the name of the user (Arnav or Mary).
In Email address, type an email address so that other repository users can contact you about this change.
In Commit message, type a brief description to help you remember why you added this file or any other details you might find helpful.
Type a name for the file.
Choose Commit file.
Now follow the same steps to add a file in a different branch. (In our example repository, that’s the branch named test-branch.) You should be able to add a file to both branches regardless of whether you’re signed in as Arnav or Mary.
Let’s change that.
Create a conditional policy in IAM
You’re going to create a policy in IAM that will deny API actions if certain conditions are met. We want to prevent users with this policy applied from updating a branch named master, but we don’t want to prevent them from viewing the branch, cloning the repository, or creating pull requests that will merge to that branch. For this reason, we want to pick and choose our APIs carefully. Looking at the Permissions Reference, the logical permissions for this are:
Now’s the time to think about what else you might want this policy to do. For example, because we don’t want users with this policy to make changes to this branch, we probably don’t want them to be able to delete it either, right? So let’s add one more permission:
The branch in which we want to deny these actions is master. The repository in which the branch resides is MyDemoRepo. We’re going to need more than just the repository name, though. We need the repository ARN. Fortunately, that’s easy to find. Just go to the AWS CodeCommit console, choose the repository, and choose Settings. The repository ARN is displayed on the General tab.
Now we’re ready to create a policy. 1. Open the IAM console at https://console.aws.amazon.com/iam/. Make sure you’re signed in with the account that has sufficient permissions to create policies, and not as Arnav or Mary. 2. In the navigation pane, choose Policies, and then choose Create policy. 3. Choose JSON, and then paste in the following:
You’ll notice a few things here. First, change the repository ARN to the ARN for your repository and include the repository name. Second, if you want to restrict access to a branch with a name different from our example, master, change that reference too.
Now let’s talk about this policy and what it does. You might be wondering why we’re using a Git reference (refs/heads) value instead of just the branch name. The answer lies in how Git references things, and how AWS CodeCommit, as a Git-based repository service, implements its APIs. A branch in Git is a simple pointer (reference) to the SHA-1 value of the head commit for that branch.
You might also be wondering about the second part of the condition, the nullification language. This is necessary because of the way git push and git-receive-pack work. Without going into too many technical details, when you attempt to push a change from a local repo to AWS CodeCommit, an initial reference call is made to AWS CodeCommit without any branch information. AWS CodeCommit evaluates that initial call to ensure that:
a) You’re authorized to make calls.
b) A repository exists with the name specified in the initial call. If you left that null out of the policy, users with that policy would be unable to complete any pushes from their local repos to the AWS CodeCommit remote repository at all, regardless of which branch they were trying to push their commits to.
Could you write a policy in such a way that the null is not required? Of course. IAM policy language is flexible. There’s an example of how to do this in the AWS CodeCommit User Guide, if you’re curious. But for the purposes of this blog post, let’s continue with this policy as written.
So what have we essentially said in this policy? We’ve asked IAM to deny the relevant CodeCommit permissions if the request is made to the resource MyDemoRepo and it meets the following condition: the reference is to refs/heads/master. Otherwise, the deny does not apply.
I’m sure you’re wondering if this policy has to be constrained to a specific repository resource like MyDemoRepo. After all, it would be awfully convenient if a single policy could apply to all branches in any repository in an AWS account, particularly since the default branch in any repository is initially the master branch. Good news! Simply replace the ARN with an *, and your policy will affect ALL branches named master in every AWS CodeCommit repository in your AWS account. Make sure that this is really what you want, though. We suggest you start by limiting the scope to just one repository, and then changing things when you’ve tested it and are happy with how it works.
When you’re sure you’ve modified the policy for your environment, choose Review policy to validate it. Give this policy a name, such as DenyChangesToMaster, provide a description of its purpose, and then choose Create policy.
Now that you have a policy, it’s time to apply and test it.
Apply the policy to a group
In theory, you could apply the policy you just created directly to any IAM user, but that really doesn’t scale well. You should apply this policy to a group, if you use IAM groups to manage users, or to a role, if your users assume a role when interacting with AWS resources.
In the IAM console, choose Groups, and then choose Developers.
On the Permissions tab, choose Attach Policy.
Choose DenyChangesToMaster, and then choose Attach policy.
Your groups now have a critical difference: users in the Developers group have an additional policy applied that restricts their actions in the master branch. In other words, Mary can continue to add files, push commits, and merge pull requests in the master branch, but Arnav cannot.
Figure 2: Two example groups in IAM, one with an additional policy applied that will prevent users in this group from making changes to the master branch
Test it out. Sign in as Arnav, and do the following:
On the Dashboard page, from the list of repositories, choose MyDemoRepo.
In the Code view, choose the branch named master.
Choose Add file, and then choose Create file, just as you did before. Provide some text, and then add the file name and your user information.
Choose Commit file.
This time you’ll see an error after choosing Commit file. It’s not a pretty message, but at the very end, you’ll see a telling phrase: “explicit deny”. That’s the policy in action. You, as Arnav, are explicitly denied PutFile, which prevents you from adding a file to the master branch. You’ll see similar results if you try other actions denied by that policy, such as deleting the master branch.
Stay signed in as Arnav, but this time add a file to test-branch. You should be able to add a file without seeing any errors. You can create a branch based on the master branch, add a file to it, and create a pull request that will merge to the master branch, all just as before. However, you cannot perform denied actions on that master branch.
Sign out as Arnav and sign in as Mary. You’ll see that as that IAM user, you can add and edit files in the master branch, merge pull requests to it, and even, although we don’t recommend this, delete it.
You can use conditional statements in policies in IAM to refine how users interact with your AWS CodeCommit repositories. This blog post showed how to use such a policy to prevent users from making changes to a branch named master. There are many other options. We hope this blog post will encourage you to experiment with AWS CodeCommit, IAM policies, and permissions. If you have any questions or suggestions, we’d love to hear from you.
I’m happy to announce that Sumerian is now generally available. You can create realistic virtual environments and scenes without having to acquire or master specialized tools for 3D modeling, animation, lighting, audio editing, or programming. Once built, you can deploy your finished creation across multiple platforms without having to write custom code or deal with specialized deployment systems and processes.
Sumerian gives you a web-based editor that you can use to quickly and easily create realistic, professional-quality scenes. There’s a visual scripting tool that lets you build logic to control how objects and characters (Sumerian Hosts) respond to user actions. Sumerian also lets you create rich, natural interactions powered by AWS services such as Amazon Lex, Polly, AWS Lambda, AWS IoT, and Amazon DynamoDB.
Sumerian was designed to work on multiple platforms. The VR and AR apps that you create in Sumerian will run in browsers that supports WebGL or WebVR and on popular devices such as the Oculus Rift, HTC Vive, and those powered by iOS or Android.
During the preview period, we have been working with a broad spectrum of customers to put Sumerian to the test and to create proof of concept (PoC) projects designed to highlight an equally broad spectrum of use cases, including employee education, training simulations, field service productivity, virtual concierge, design and creative, and brand engagement. Fidelity Labs (the internal R&D unit of Fidelity Investments), was the first to use a Sumerian host to create an engaging VR experience. Cora (the host) lives within a virtual chart room. She can display stock quotes, pull up company charts, and answer questions about a company’s performance. This PoC uses Amazon Polly to implement text to speech and Amazon Lex for conversational chatbot functionality. Read their blog post and watch the video inside to see Cora in action:
Now that Sumerian is generally available, you have the power to create engaging AR, VR, and 3D experiences of your own. To learn more, visit the Amazon Sumerian home page and then spend some quality time with our extensive collection of Sumerian Tutorials.
Attention, case modders: take a look at the Brutus 2, an extremely snazzy computer case with a partly transparent, animated side panel that’s powered by a Pi. Daniel Otto and Carsten Lehman have a current crowdfunder for the case; their video is in German, but the looks of the build speak for themselves. There are some truly gorgeous effects here.
Vorbestellungen ab sofort auf https://www.startnext.com/brutus2 Weitere Infos zu uns auf: https://3nb.de https://www.facebook.com/3nb.de https://www.instagram.com/3nb.de Über 3nb: – GbR aus Leipzig, gegründet 2017 – wir kommen aus den Bereichen Elektronik und Informatik – erstes Produkt: der Brutus One ein Gaming PC mit transparentem Display in der Seite Kurzinfo Brutus 2: – Markencomputergehäuse für Gaming- /Casemoddingszene – Besonderheit: animiertes Seitenfenster angesteuert mit einem Raspberry Pi – Vorteile von unserem Case: o Case ist einzeln lieferbar und nicht nur als komplett-PC o kein Leistungsverbrauch der Grafikkarte dank integriertem Raspberry Pi o bessere Darstellung von Texten und Grafiken durch unscharfen Hintergrund
What’s case modding?
Case modding just means modifying your computer or gaming console’s case, and it’s very popular in the gaming community. Some mods are functional, while others improve the way the case looks. Lots of dedicated gamers don’t only want a powerful computer, they also want it to look amazing — at home, or at LAN parties and games tournaments.
The Brutus 2 case
The Brutus 2 case is made by Daniel and Carsten’s startup, 3nb electronics, and it’s a product that is officially Powered by Raspberry Pi. Its standout feature is the semi-transparent TFT screen, which lets you play any video clip you choose while keeping your gaming hardware on display. It looks incredibly cool. All the graphics for the case’s screen are handled by a Raspberry Pi, so it doesn’t use any of your main PC’s GPU power and your gaming won’t suffer.
To use Brutus 2, you just need to run a small desktop application on your PC to choose what you want to display on the case. A number of neat animations are included, and you can upload your own if you want.
So far, the app only runs on Windows, but 3nb electronics are planning to make the code open-source, so you can modify it for other operating systems, or to display other file types. This is true to the spirit of the case modding and Raspberry Pi communities, who love adapting, retrofitting, and overhauling projects and code to fit their needs.
Daniel and Carsten say that one of their campaign’s stretch goals is to implement more functionality in the Brutus 2 app. So in the future, the case could also show things like CPU temperature, gaming stats, and in-game messages. Of course, there’s nothing stopping you from integrating features like that yourself.
If you have any questions about the case, you can post them directly to Daniel and Carsten here.
The crowdfunding campaign
The Brutus 2 campaign on Startnext is currently halfway to its first funding goal of €10000, with over three weeks to go until it closes. If you’re quick, you still be may be able to snatch one of the early-bird offers. And if your whole guild NEEDS this, that’s OK — there are discounts for bulk orders.
I’ve been busy trying to replicate the “eFail” PGP/SMIME bug. I thought I’d write up some notes.
PGP and S/MIME encrypt emails, so that eavesdroppers can’t read them. The bugs potentially allow eavesdroppers to take the encrypted emails they’ve captured and resend them to you, reformatted in a way that allows them to decrypt the messages.
Disable remote/external content in email
The most important defense is to disable “external” or “remote” content from being automatically loaded. This is when HTML-formatted emails attempt to load images from remote websites. This happens legitimately when they want to display images, but not fill up the email with them. But most of the time this is illegitimate, they hide images on the webpage in order to track you with unique IDs and cookies. For example, this is the code at the end of an email from politician Bernie Sanders to his supporters. Notice the long random number assigned to track me, and the width/height of this image is set to one pixel, so you don’t even see it:
Such trackers are so pernicious they are disabled by default in most email clients. This is an example of the settings in Thunderbird:
The problem is that as you read email messages, you often get frustrated by the fact the error messages and missing content, so you keep adding exceptions:
The correct defense against this eFail bug is to make sure such remote content is disabled and that you have no exceptions, or at least, no HTTP exceptions. HTTPS exceptions (those using SSL) are okay as long as they aren’t to a website the attacker controls. Unencrypted exceptions, though, the hacker can eavesdrop on, so it doesn’t matter if they control the website the requests go to. If the attacker can eavesdrop on your emails, they can probably eavesdrop on your HTTP sessions as well.
Some have recommended disabling PGP and S/MIME completely. That’s probably overkill. As long as the attacker can’t use the “remote content” in emails, you are fine. Likewise, some have recommend disabling HTML completely. That’s not even an option in any email client I’ve used — you can disable sending HTML emails, but not receiving them. It’s sufficient to just disable grabbing remote content, not the rest of HTML email rendering.
I couldn’t replicate the direct exfiltration
There rare two related bugs. One allows direct exfiltration, which appends the decrypted PGP email onto the end of an IMG tag (like one of those tracking tags), allowing the entire message to be decrypted.
An example of this is the following email. This is a standard HTML email message consisting of multiple parts. The trick is that the IMG tag in the first part starts the URL (blog.robertgraham.com/…) but doesn’t end it. It has the starting quotes in front of the URL but no ending quotes. The ending will in the next chunk.
The next chunk isn’t HTML, though, it’s PGP. The PGP extension (in my case, Enignmail) will detect this and automatically decrypt it. In this case, it’s some previous email message I’ve received the attacker captured by eavesdropping, who then pastes the contents into this email message in order to get it decrypted.
What should happen at this point is that Thunderbird will generate a request (if “remote content” is enabled) to the blog.robertgraham.com server with the decrypted contents of the PGP email appended to it. But that’s not what happens. Instead, I get this:
I am indeed getting weird stuff in the URL (the bit after the GET /), but it’s not the PGP decrypted message. Instead what’s going on is that when Thunderbird puts together a “multipart/mixed” message, it adds it’s own HTML tags consisting of lines between each part. In the email client it looks like this:
The HTML code it adds looks like:
That’s what you see in the above URL, all this code up to the first quotes. Those quotes terminate the quotes in the URL from the first multipart section, causing the rest of the content to be ignored (as far as being sent as part of the URL).
So at least for the latest version of Thunderbird, you are accidentally safe, even if you have “remote content” enabled. Though, this is only according to my tests, there may be a work around to this that hackers could exploit.
In the old days, email was sent plaintext over the wire so that it could be passively eavesdropped on. Nowadays, most providers send it via “STARTTLS”, which sorta encrypts it. Attackers can still intercept such email, but they have to do so actively, using man-in-the-middle. Such active techniques can be detected if you are careful and look for them.
Some organizations don’t care. Apparently, some nation states are just blocking all STARTTLS and forcing email to be sent unencrypted. Others do care. The NSA will passively sniff all the email they can in nations like Iraq, but they won’t actively intercept STARTTLS messages, for fear of getting caught.
The consequence is that it’s much less likely that somebody has been eavesdropping on you, passively grabbing all your PGP/SMIME emails. If you fear they have been, you should look (e.g. send emails from GMail and see if they are intercepted by sniffing the wire).
You’ll know if you are getting hacked
If somebody attacks you using eFail, you’ll know. You’ll get an email message formatted this way, with multipart/mixed components, some with corrupt HTML, some encrypted via PGP. This means that for the most part, your risk is that you’ll be attacked only once — the hacker will only be able to get one message through and decrypt it before you notice that something is amiss. Though to be fair, they can probably include all the emails they want decrypted as attachments to the single email they sent you, so the risk isn’t necessarily that you’ll only get one decrypted.
As mentioned above, a lot of attackers (e.g. the NSA) won’t attack you if its so easy to get caught. Other attackers, though, like anonymous hackers, don’t care.
Somebody ought to write a plugin to Thunderbird to detect this.
It only works if attackers have already captured your emails (though, that’s why you use PGP/SMIME in the first place, to guard against that).
It only works if you’ve enabled your email client to automatically grab external/remote content.
It seems to not be easily reproducible in all cases.
Instead of disabling PGP/SMIME, you should make sure your email client hast remote/external content disabled — that’s a huge privacy violation even without this bug.
Notes: The default email client on the Mac enables remote content by default, which is bad:
If your day has been a little fraught so far, watch this video. It opens with a tableau of methodically laid-out components and then shows them soldered, screwed, and slotted neatly into place. Everything fits perfectly; nothing needs percussive adjustment. Then it shows us glimpses of an AR future just like the one promised in the less dystopian comics and TV programmes of my 1980s childhood. It is all very soothing, and exactly what I needed.
Transform any surface into mixed-reality using Raspberry Pi, a laser projector, and Android Things. Android Experiments – http://experiments.withgoogle.com/android/lantern Lantern project site – http://nordprojects.co/lantern check below to make your own ↓↓↓ Get the code – https://github.com/nordprojects/lantern Build the lamp – https://www.hackster.io/nord-projects/lantern-9f0c28
Creating augmented reality with projection
We’ve seen plenty of Raspberry Pi IoT builds that are smart devices for the home; they add computing power to things like lights, door locks, or toasters to make these objects interact with humans and with their environment in new ways. Nord Projects‘ Lantern takes a different approach. In their words, it:
imagines a future where projections are used to present ambient information, and relevant UI within everyday objects. Point it at a clock to show your appointments, or point to speaker to display the currently playing song. Unlike a screen, when Lantern’s projections are no longer needed, they simply fade away.
Lantern is set up so that you can connect your wireless device to it using Google Nearby. This means there’s no need to create an account before you can dive into augmented reality.
Your own open-source AR lamp
Nord Projects collaborated on Lantern with Google’s Android Things team. They’ve made it fully open-source, so you can find the code on GitHub and also download their parts list, which includes a Pi, an IKEA lamp, an accelerometer, and a laser projector. Build instructions are at hackster.io and on GitHub.
This is a particularly clear tutorial, very well illustrated with photos and GIFs, and once you’ve sourced and 3D-printed all of the components, you shouldn’t need a whole lot of experience to put everything together successfully. Since everything is open-source, though, if you want to adapt it — for example, if you’d like to source a less costly projector than the snazzy one used here — you can do that too.
The instructions walk you through the mechanical build and the wiring, as well as installing Android Things and Nord Projects’ custom software on the Raspberry Pi. Once you’ve set everything up, an accelerometer connected to the Pi’s GPIO pins lets the lamp know which surface it is pointing at. A companion app on your mobile device lets you choose from the mini apps that work on that surface to select the projection you want.
The designers are making several mini apps available for Lantern, including the charmingly named Space Porthole: this uses Processing and your local longitude and latitude to project onto your ceiling the stars you’d see if you punched a hole through to the sky, if it were night time, and clear weather. Wouldn’t you rather look at that than deal with the ant problem in your kitchen or tackle your GitHub notifications?
What would you like to project onto your living environment? Let us know in the comments!
At the moment I’m spending my evenings watching all of Star Trek in order. Yes, I have watched it before (but with some really big gaps). Yes, including the animated series (I’m up to The Terratin Incident). So I’m gratified to find this beautiful The Original Series–style tricorder build.
At this year’s Replica Prop Forum showcase, we meet up once again wtih Brian Mix, who brought his new Star Trek TOS Tricorder. This beautiful replica captures the weight and finish of the filming hand prop, and Brian has taken it one step further with some modern-day electronics!
A what now?
If you don’t know what a tricorder is, which I guess is faintly possible, the easiest way I can explain is to steal words that Liz wrote when Recanthamade one back in 2013. It’s “a made-up thing used by the crew of the Enterprise to measure stuff, store data, and scout ahead remotely when exploring strange new worlds, seeking out new life and new civilisations, and all that jazz.”
A brief history of Picorders
We’ve seen other Raspberry Pi–based realisations of this iconic device. Recantha’s LEGO-cased tricorder delivered some authentic functionality, including temperature sensors, an ultrasonic distance sensor, a photosensor, and a magnetometer. Michael Hahn’s tricorder for element14’s Sci-Fi Your Pi competition in 2015 packed some similar functions, along with Original Series audio effects, into a neat (albeit non-canon) enclosure.
Brian Mix’s Original Series tricorder
Brian Mix’s tricorder, seen in the video above from Tested at this year’s Replica Prop Forum showcase, is based on a high-quality kit into which, he discovered, a Raspberry Pi just fits. He explains that the kit is the work of the late Steve Horch, a special effects professional who provided props for later Star Trek series, including the classic Deep Space Nine episode Trials and Tribble-ations.
Dax, equipped for time travel
This episode’s plot required sets and props — including tricorders — replicating the USS Enterprise of The Original Series, and Steve Horch provided many of these. Thus, a tricorder kit from him is about as close to authentic as you can possibly find unless you can get your hands on a screen-used prop. The Pi allows Brian to drive a real display and a speaker: “Being the geek that I am,” he explains, “I set it up to run every single Original Series Star Trek episode.”
Even more wonderful hypothetical tricorders that I would like someone to make
This tricorder is beautiful, and it makes me think how amazing it would be to squeeze in some of the sensor functionality of the devices depicted in the show. Space in the case is tight, but it looks like there might be a little bit of depth to spare — enough for an IMU, maybe, or a temperature sensor. I’m certain the future will bring more Pi tricorder builds, and I, for one, can’t wait. Please tell us in the comments if you’re planning something along these lines, and, well, I suppose some other sci-fi franchises have decent Pi project potential too, so we could probably stand to hear about those.
If you’re commenting, no spoilers please past The Animated Series S1 E11. Thanks.
Version 1.14 of the Battle for Wesnoth role-playing game — the first release in over three years — is available. “Along with the long-awaited debut on Steam, this new release series brings forth a vast number of additions and changes in all areas: a new single-player campaign, a visual and functional refresh of the multiplayer lobby and add-ons manager, a refurbished display engine, new unit graphics and animations, and much more.”
If you store sensitive or confidential data in Amazon DynamoDB, you might want to encrypt that data as close as possible to its origin so your data is protected throughout its lifecycle.
You can use the DynamoDB Encryption Client to protect your table data before you send it to DynamoDB. Encrypting your sensitive data in transit and at rest helps assure that your plaintext data isn’t available to any third party, including AWS.
You don’t need to be a cryptography expert to use the DynamoDB Encryption Client. The encryption and signing elements are designed to work with your existing DynamoDB applications. After you create and configure the required components, the DynamoDB Encryption Client transparently encrypts and signs your table items when you call PutItem and verifies and decrypts them when you call GetItem.
You can create your own custom components, or use the basic implementations that are included in the library. We’ve made sure that the classes that we provide implement strong and secure cryptography.
The DynamoDB Encryption Client is now available in Python, as well as Java. All supported language implementations are interoperable. For example, you can encrypt table data with the Python library and decrypt it with the Java library.
The DynamoDB Encryption Client is an open-source project. We hope that you will join us in developing the libraries and writing great documentation.
How it works
The DynamoDB Encryption Client processes one table item at a time. First, it encrypts the values (but not the names) of attributes that you specify. Then, it calculates a signature over the attributes that you specify, so you can detect unauthorized changes to the item as a whole, including adding or deleting attributes, or substituting one encrypted value for another.
However, attribute names, and the names and values in the primary key (the partition key and sort key, if one is provided) must remain in plaintext to make the item discoverable. They’re included in the signature by default.
Important: Do not put any sensitive data in the table name, attribute names, the names and values of the primary key attributes, or any attribute values that you tell the client not to encrypt.
How to use it
I’ll demonstrate how to use the DynamoDB Encryption Client in Python with a simple example. I’ll encrypt and sign one table item, and then add it to an existing table. This example uses a test item with arbitrary data, but you can use a similar procedure to protect a table item that contains highly sensitive data, such as a customer’s personal information.
I’ll start by creating a DynamoDB table resource that represents an existing table. If you use the code, be sure to supply a valid table name.
# Create a DynamoDB table
table = boto3.resource('dynamodb').Table(table_name)
Step 2: Create a cryptographic materials provider
Next, create an instance of a cryptographic materials provider (CMP). The CMP is the component that gathers the encryption and signing keys that are used to encrypt and sign your table items. The CMP also determines the encryption algorithms that are used and whether you create unique keys for every item or reuse them.
The DynamoDB Encryption Client includes several CMPs and you can create your own. And, if you’re in doubt, we help you to choose a CMP that fits your application and its security requirements.
To create a Direct KMS Provider, you specify an AWS KMS customer master key. Be sure to replace the fictitious customer master key ID (the value of aws-cmk-id) in this example with a valid one.
# Create a Direct KMS provider. Pass in a valid KMS customer master key.
aws_cmk_id = '1234abcd-12ab-34cd-56ef-1234567890ab'
aws_kms_cmp = AwsKmsCryptographicMaterialsProvider(key_id=aws_cmk_id)
Step 3: Create an attribute actions object
An attribute actions object tells the DynamoDB Encryption Client which item attribute values to encrypt and which attributes to include in the signature. The options are: ENCRYPT_AND_SIGN, SIGN_ONLY, and DO_NOTHING.
This sample attribute action encrypts and signs all attributes values except for the value of the test attribute; that attribute is neither encrypted nor included in the signature.
# Tell the encrypted table to encrypt and sign all attributes except one.
actions = AttributeActions(
If you’re using a helper class, such as the EncryptedTable class that I use in the next step, you can’t specify an attribute action for the primary key. The helper classes make sure that the primary key is signed, but never encrypted (SIGN_ONLY).
Step 4: Create an encrypted table
Now I can use the original table object, along with the materials provider and attribute actions, to create an encrypted table.
# Use these objects to create an encrypted table resource.
encrypted_table = EncryptedTable(
In this example, I’m using the EncryptedTable helper class, which adds encryption features to the DynamoDB Table class in the AWS SDK for Python (Boto 3). The DynamoDB Encryption Client in Python also includes EncryptedClient and EncryptedResource helper classes.
The DynamoDB Encryption Client helper classes call the DescribeTable operation to find the primary key. The application that runs the code must have permission to call the operation.
We’re done configuring the client. Now, we can encrypt, sign, verify, and decrypt table items.
To view the encrypted item, call the GetItem operation on the original table object, instead of the encrypted_table object. It gets the item from the DynamoDB table without verifying and decrypting it.
Here’s an excerpt of the output that displays the encrypted item:
Figure 1: Output that displays the encrypted item
Client-side or server-side encryption?
The DynamoDB Encryption Client is designed for client-side encryption, where you encrypt your data before you send it to DynamoDB.
But, you have other options. DynamoDB supports encryption at rest, a server-side encryption option that transparently encrypts the data in your table whenever DynamoDB saves the table to disk. You can even use both the DynamoDB Encryption Client and encryption at rest together. The encrypted and signed items that the client generates are standard table items that have binary data in their attribute values. Your choice depends on the sensitivity of your data and the security requirements of your application.
Although the Java and Python versions of the DynamoDB Encryption Client are fully compatible, the DynamoDB Encryption Client isn’t compatible with other client-side encryption libraries, such as the AWS Encryption SDK or the S3 Encryption Client. You can’t encrypt data with one library and decrypt it with another. For data that you store in DynamoDB, we recommend the DynamoDB Encryption Client.
Encryption is crucial
Using tools like the DynamoDB Encryption Client helps you to protect your table data and comply with the security requirements for your application. We hope that you use the client and join us in developing it on GitHub.
This video demos a real-like Pokedex, complete with visual recognition, that I created using a Raspberry Pi, Python, and Deep Learning. You can find the entire blog post, including code, using this link: https://www.pyimagesearch.com/2018/04/30/a-fun-hands-on-deep-learning-project-for-beginners-students-and-hobbyists/ Music credit to YouTube user “No Copyright” for providing royalty free music: https://www.youtube.com/watch?v=PXpjqURczn8
The history of Pokémon in 30 seconds
The Pokémon franchise was created by video game designer Satoshi Tajiri in 1995. In the fictional world of Pokémon, Pokémon Trainers explore the vast landscape, catching and training small creatures called Pokémon. To date, there are 802 different types of Pokémon. They range from the ever recognisable Pikachu, a bright yellow electric Pokémon, to the highly sought-after Shiny Charizard, a metallic, playing-card-shaped Pokémon that your mate Alex claims she has in mint condition, but refuses to show you.
In the world of Pokémon, children as young as ten-year-old protagonist and all-round annoyance Ash Ketchum are allowed to leave home and wander the wilderness. There, they hunt vicious, deadly creatures in the hope of becoming a Pokémon Master.
Adrian’s deep learning Pokédex
Adrian is a bit of a deep learning pro, as demonstrated by his Santa/Not Santa detector, which we wrote about last year. For that project, he also provided a great explanation of what deep learning actually is. In a nutshell:
…a subfield of machine learning, which is, in turn, a subfield of artificial intelligence (AI).While AI embodies a large, diverse set of techniques and algorithms related to automatic reasoning (inference, planning, heuristics, etc), the machine learning subfields are specifically interested in pattern recognition and learning from data.
As with his earlier Raspberry Pi project, Adrian uses the Keras deep learning model and the TensorFlow backend, plus a few other packages such as Adrian’s own imutils functions and OpenCV.
Adrian trained a Convolutional Neural Network using Keras on a dataset of 1191 Pokémon images, obtaining 96.84% accuracy. As Adrian explains, this model is able to identify Pokémon via still image and video. It’s perfect for creating a Pokédex – an interactive Pokémon catalogue that should, according to the franchise, be able to identify and read out information on any known Pokémon when captured by camera. More information on model training can be found on Adrian’s blog.
For the physical build, a Raspberry Pi 3 with camera module is paired with the Raspberry Pi 7″ touch display to create a portable Pokédex. And while Adrian comments that the same result can be achieved using your home computer and a webcam, that’s not how Adrian rolls as a Raspberry Pi fan.
Plus, the smaller size of the Pi is perfect for one of you to incorporate this deep learning model into a 3D-printed Pokédex for ultimate Pokémon glory, pretty please, thank you.
Adrian has gone into impressive detail about how the project works and how you can create your own on his blog, pyimagesearch. So if you’re interested in learning more about deep learning, and making your own Pokédex, be sure to visit.
Enterprises adopt containers because they recognize the benefits: speed, agility, portability, and high compute density. They understand how accelerating application delivery and deployment pipelines makes it possible to rapidly slipstream new features to customers. Although the benefits are indisputable, this acceleration raises concerns about security and corporate compliance with software governance. In this blog post, I provide a solution that shows how Layered Insight, the pioneer and global leader in container-native application protection, can be used with seamless application build and delivery pipelines like those available in AWS CodeBuild to address these concerns.
Layered Insight solutions
Layered Insight enables organizations to unify DevOps and SecOps by providing complete visibility and control of containerized applications. Using the industry’s first embedded security approach, Layered Insight solves the challenges of container performance and protection by providing accurate insight into container images, adaptive analysis of running containers, and automated enforcement of container behavior.
AWS CodeBuild is a fully managed build service that compiles source code, runs tests, and produces software packages that are ready to deploy. With CodeBuild, you don’t need to provision, manage, and scale your own build servers. CodeBuild scales continuously and processes multiple builds concurrently, so your builds are not left waiting in a queue. You can get started quickly by using prepackaged build environments, or you can create custom build environments that use your own build tools.
Security and compliance concerns span the lifecycle of application containers. Common concerns include:
Visibility into the container images. You need to verify the software composition information of the container image to determine whether known vulnerabilities associated with any of the software packages and libraries are included in the container image.
Governance of container images is critical because only certain open source packages/libraries, of specific versions, should be included in the container images. You need support for mechanisms for blacklisting all container images that include a certain version of a software package/library, or only allowing open source software that come with a specific type of license (such as Apache, MIT, GPL, and so on). You need to be able to address challenges such as:
· Defining the process for image compliance policies at the enterprise, department, and group levels.
· Preventing the images that fail the compliance checks from being deployed in critical environments, such as staging, pre-prod, and production.
Visibility into running container instances is critical, including:
· CPU and memory utilization.
· Security of the build environment.
· All activities (system, network, storage, and application layer) of the application code running in each container instance.
Protection of running container instances that is:
· Zero-touch to the developers (not an SDK-based approach).
· Zero touch to the DevOps team and doesn’t limit the portability of the containerized application.
· This protection must retain the option to switch to a different container stack or orchestration layer, or even to a different Container as a Service (CaaS ).
· And it must be a fully automated solution to SecOps, so that the SecOps team doesn’t have to manually analyze and define detailed blacklist and whitelist policies.
In AWS CodeCommit, we have three projects: ● “Democode” is a simple Java application, with one buildspec to build the app into a Docker container (run by build-demo-image CodeBuild project), and another to instrument said container (instrument-image CodeBuild project). The resulting container is stored in ECR repo javatestasjavatest:20180415-layered. This instrumented container is running in AWS Fargate cluster demo-java-appand can be seen in the Layered Insight runtime console as the javatestapplication in us-east-1. ● aws-codebuild-docker-imagesis a clone of the official aws-codebuild-docker-images repo on GitHub . This CodeCommit project is used by the build-python-builder CodeBuild project to build the python 3.3.6 codebuild image and is stored at the codebuild-python ECR repo. We then manually instructed the Layered Insight console to instrument the image. ● scan-java-imagecontains just a buildspec.yml file. This file is used by the scan-java-image CodeBuild project to instruct Layered Assessment to perform a vulnerability scan of the javatest container image built previously, and then run the scan results through a compliance policy that states there should be no medium vulnerabilities. This build fails — but in this case that is a success: the scan completes successfully, but compliance fails as there are medium-level issues found in the scan.
This build is performed using the instrumented version of the Python 3.3.6 CodeBuild image, so the activity of the processes running within the build are recorded each time within the LI console.
Build container image
Create or use a CodeCommit project with your application. To build this image and store it in Amazon Elastic Container Registry (Amazon ECR), add a buildspec file to the project and build a container image and create a CodeBuild project.
Scan container image
Once the image is built, create a new buildspec in the same project or a new one that looks similar to below (update ECR URL as necessary):
- echo Pulling down LI Scan API client scripts
- git clone https://github.com/LayeredInsight/scan-api-example-python.git
- echo Setting up LI Scan API client
- cd scan-api-example-python
- pip install layint_scan_api
- pip install -r requirements.txt
- echo Scanning container started on `date`
- IMAGEID=$(./li_add_image --name <aws-region>.amazonaws.com/javatest:20180415)
- ./li_wait_for_scan -v --imageid $IMAGEID
- ./li_run_image_compliance -v --imageid $IMAGEID --policyid PB15260f1acb6b2aa5b597e9d22feffb538256a01fbb4e5a95
Add the buildspec file to the git repo, push it, and then build a CodeBuild project using with the instrumented Python 3.3.6 CodeBuild image at <aws-region>.amazonaws.com/codebuild-python:3.3.6-layered. Set the following environment variables in the CodeBuild project: ● LI_APPLICATIONNAME – name of the build to display ● LI_LOCATION – location of the build project to display ● LI_API_KEY – ApiKey:<key-name>:<api-key> ● LI_API_HOST – location of the Layered Insight API service
Instrument container image
Next, to instrument the new container image:
In the Layered Insight runtime console, ensure that the ECR registry and credentials are defined (click the Setup icon and the ‘+’ sign on the top right of the screen to add a new container registry). Note the name given to the registry in the console, as this needs to be referenced in the li_add_imagecommand in the script, below.
Next, add a new buildspec (with a new name) to the CodeCommit project, such as the one shown below. This code will download the Layered Insight runtime client, and use it to instruct the Layered Insight service to instrument the image that was just built:
echo Pulling down LI API Runtime client scripts
git clone https://github.com/LayeredInsight/runtime-api-example-python
echo Setting up LI API client
pip install layint-runtime-api
pip install -r requirements.txt
echo Instrumentation started on `date`
./li_add_image --registry "Javatest ECR" --name IMAGE_NAME:TAG --description "IMAGE DESCRIPTION" --policy "Default Policy" --instrument --wait --verbose
Commit and push the new buildspec file.
Going back to CodeBuild, create a new project, with the same CodeCommit repo, but this time select the new buildspec file. Use a Python 3.3.6 builder – either the AWS or LI Instrumented version.
Run the build, again on the master branch.
If everything runs successfully, a new image should appear in the ECR registry with a -layered suffix. This is the instrumented image.
Run instrumented container image
When the instrumented container is now run — in ECS, Fargate, or elsewhere — it will log data back to the Layered Insight runtime console. It’s appearance in the console can be modified by setting the LI_APPLICATIONNAME and LI_LOCATION environment variables when running the container.
In the above blog we have provided you steps needed to embed governance and runtime security in your build pipelines running on AWS CodeBuild using Layered Insight.
Last week, we shared the first half of our Q&A with Raspberry Pi Trading CEO and Raspberry Pi creator Eben Upton. Today we follow up with all your other questions, including your expectations for a Raspberry Pi 4, Eben’s dream add-ons, and whether we really could go smaller than the Zero.
Get your questions to us now using #AskRaspberryPi on Twitter
With internet security becoming more necessary, will there be automated versions of VPN on an SD card?
There are already third-party tools which turn your Raspberry Pi into a VPN endpoint. Would we do it ourselves? Like the power button, it’s one of those cases where there are a million things we could do and so it’s more efficient to let the community get on with it.
Just to give a counterexample, while we don’t generally invest in optimising for particular use cases, we did invest a bunch of money into optimising Kodi to run well on Raspberry Pi, because we found that very large numbers of people were using it. So, if we find that we get half a million people a year using a Raspberry Pi as a VPN endpoint, then we’ll probably invest money into optimising it and feature it on the website as we’ve done with Kodi. But I don’t think we’re there today.
Have you ever seen any Pis running and doing important jobs in the wild, and if so, how does it feel?
It’s amazing how often you see them driving displays, for example in radio and TV studios. Of course, it feels great. There’s something wonderful about the geographic spread as well. The Raspberry Pi desktop is quite distinctive, both in its previous incarnation with the grey background and logo, and the current one where we have Greg Annandale’s road picture.
And so it’s funny when you see it in places. Somebody sent me a video of them teaching in a classroom in rural Pakistan and in the background was Greg’s picture.
Raspberry Pi 4!?!
There will be a Raspberry Pi 4, obviously. We get asked about it a lot. I’m sticking to the guidance that I gave people that they shouldn’t expect to see a Raspberry Pi 4 this year. To some extent, the opportunity to do the 3B+ was a surprise: we were surprised that we’ve been able to get 200MHz more clock speed, triple the wireless and wired throughput, and better thermals, and still stick to the $35 price point.
We’re up against the wall from a silicon perspective; we’re at the end of what you can do with the 40nm process. It’s not that you couldn’t clock the processor faster, or put a larger processor which can execute more instructions per clock in there, it’s simply about the energy consumption and the fact that you can’t dissipate the heat. So we’ve got to go to a smaller process node and that’s an order of magnitude more challenging from an engineering perspective. There’s more effort, more risk, more cost, and all of those things are challenging.
With 3B+ out of the way, we’re going to start looking at this now. For the first six months or so we’re going to be figuring out exactly what people want from a Raspberry Pi 4. We’re listening to people’s comments about what they’d like to see in a new Raspberry Pi, and I’m hoping by early autumn we should have an idea of what we want to put in it and a strategy for how we might achieve that.
Could you go smaller than the Zero?
The challenge with Zero as that we’re periphery-limited. If you run your hand around the unit, there is no edge of that board that doesn’t have something there. So the question is: “If you want to go smaller than Zero, what feature are you willing to throw out?”
It’s a single-sided board, so you could certainly halve the PCB area if you fold the circuitry and use both sides, though you’d have to lose something. You could give up some GPIO and go back to 26 pins like the first Raspberry Pi. You could give up the camera connector, you could go to micro HDMI from mini HDMI. You could remove the SD card and just do USB boot. I’m inventing a product live on air! But really, you could get down to two thirds and lose a bunch of GPIO – it’s hard to imagine you could get to half the size.
What’s the one feature that you wish you could outfit on the Raspberry Pi that isn’t cost effective at this time? Your dream feature.
Well, more memory. There are obviously technical reasons why we don’t have more memory on there, but there are also market reasons. People ask “why doesn’t the Raspberry Pi have more memory?”, and my response is typically “go and Google ‘DRAM price’”. We’re used to the price of memory going down. And currently, we’re going through a phase where this has turned around and memory is getting more expensive again.
Machine learning would be interesting. There are machine learning accelerators which would be interesting to put on a piece of hardware. But again, they are not going to be used by everyone, so according to our method of pricing what we might add to a board, machine learning gets treated like a $50 chip. But that would be lovely to do.
Which citizen science projects using the Pi have most caught your attention?
I like the wildlife camera projects. We live out in the countryside in a little village, and we’re conscious of being surrounded by nature but we don’t see a lot of it on a day-to-day basis. So I like the nature cam projects, though, to my everlasting shame, I haven’t set one up yet. There’s a range of them, from very professional products to people taking a Raspberry Pi and a camera and putting them in a plastic box. So those are good fun.
How does it feel to go to bed every day knowing you’ve changed the world for the better in such a massive way?
What feels really good is that when we started this in 2006 nobody else was talking about it, but now we’re part of a very broad movement.
We were in a really bad way: we’d seen a collapse in the number of applicants applying to study Computer Science at Cambridge and elsewhere. In our view, this reflected a move away from seeing technology as ‘a thing you do’ to seeing it as a ‘thing that you have done to you’. It is problematic from the point of view of the economy, industry, and academia, but most importantly it damages the life prospects of individual children, particularly those from disadvantaged backgrounds. The great thing about STEM subjects is that you can’t fake being good at them. There are a lot of industries where your Dad can get you a job based on who he knows and then you can kind of muddle along. But if your dad gets you a job building bridges and you suck at it, after the first or second bridge falls down, then you probably aren’t going to be building bridges anymore. So access to STEM education can be a great driver of social mobility.
By the time we were launching the Raspberry Pi in 2012, there was this wonderful movement going on. Code Club, for example, and CoderDojo came along. Lots of different ways of trying to solve the same problem. What feels really, really good is that we’ve been able to do this as part of an enormous community. And some parts of that community became part of the Raspberry Pi Foundation – we merged with Code Club, we merged with CoderDojo, and we continue to work alongside a lot of these other organisations. So in the two seconds it takes me to fall asleep after my face hits the pillow, that’s what I think about.
We’re currently advertising a Programme Manager role in New Delhi, India. Did you ever think that Raspberry Pi would be advertising a role like this when you were bringing together the Foundation?
No, I didn’t.
But if you told me we were going to be hiring somewhere, India probably would have been top of my list because there’s a massive IT industry in India. When we think about our interaction with emerging markets, India, in a lot of ways, is the poster child for how we would like it to work. There have already been some wonderful deployments of Raspberry Pi, for example in Kerala, without our direct involvement. And we think we’ve got something that’s useful for the Indian market. We have a product, we have clubs, we have teacher training. And we have a body of experience in how to teach people, so we have a physical commercial product as well as a charitable offering that we think are a good fit.
It’s going to be massive.
What is your favourite BBC type-in listing?
There was a game called Codename: Druid. There is a famous game called Codename: Droid which was the sequel to Stryker’s Run, which was an awesome, awesome game. And there was a type-in game called Codename: Druid, which was at the bottom end of what you would consider a commercial game.
And I remember typing that in. And what was really cool about it was that the next month, the guy who wrote it did another article that talks about the memory map and which operating system functions used which bits of memory. So if you weren’t going to do disc access, which bits of memory could you trample on and know the operating system would survive.
I still like type-in listings. The Raspberry Pi 2018 Annual has a type-in listing that I wrote for a Babbage versus Bugs game. I will say that’s not the last type-in listing you will see from me in the next twelve months. And if you download the PDF, you could probably copy and paste it into your favourite text editor to save yourself some time.
Discover new sounds and explore the role of machine learning in music production and sound research with the NSynth Super, an ongoing project from Google’s Magenta research team that you can build at home.
Part of the ongoing Magenta research project within Google, NSynth Super explores the ways in which machine learning tools help artists and musicians be creative.
“Technology has always played a role in creating new types of sounds that inspire musicians — from the sounds of distortion to the electronic sounds of synths,” explains the team behind the NSynth Super. “Today, advances in machine learning and neural networks have opened up new possibilities for sound generation.”
Using TensorFlow, the Magenta team builds tools and interfaces that let artists and musicians use machine learning in their work. The NSynth Super AI algorithm uses deep neural networking to investigate the character of sounds. It then builds new sounds based on these characteristics instead of simply mixing sounds together.
Using an autoencoder, it extracts 16 defining temporal features from each input. These features are then interpolated linearly to create new embeddings (mathematical representations of each sound). These new embeddings are then decoded into new sounds, which have the acoustic qualities of both inputs.
The team publishes all hardware designs and software that are part of their ongoing research under open-source licences, allowing you to build your own synth.
Build your own NSynth Super
Using these open-source tools, Andrew Black has produced his own NSynth Super, demoed in the video above. Andrew’s list of build materials includes a Raspberry Pi 3, potentiometers, rotary encoders, and the Adafruit 1.3″ OLED display. Magenta also provides Gerber files for you to fabricate your own PCB.
Once fabricated, the PCB includes a table of contents for adding components.
The Raspberry Pi has been widely used for music production and music builds. Be it retrofitting a boombox, distributing music atop Table Mountain, or coding tracks with Sonic Pi, the Pi offers endless opportunities for musicians and music lovers to expand their repertoire of builds and instruments.
Almost a decade ago, my colleague Deepak Singh introduced the AWS Public Datasets in his post Paging Researchers, Analysts, and Developers. I’m happy to report that Deepak is still an important part of the AWS team and that the Public Datasets program is still going strong!
Today we are announcing a new take on open and public data, the Registry of Open Data on AWS, or RODA. This registry includes existing Public Datasets and allows anyone to add their own datasets so that they can be accessed and analyzed on AWS.
Inside the Registry The home page lists all of the datasets in the registry:
Entering a search term shrinks the list so that only the matching datasets are displayed:
Each dataset has an associated detail page, including usage examples, license info, and the information needed to locate and access the dataset on AWS:
In this case, I can access the data with a simple CLI command:
I could also access it programmatically, or download data to my EC2 instance.
Adding to the Repository If you have a dataset that is publicly available and would like to add it to RODA , you can simply send us a pull request. Head over to the open-data-registry repo, read the CONTRIBUTING document, and create a YAML file that describes your dataset, using one of the existing files in the datasets directory as a model:
We’ll review pull requests regularly; you can “star” or watch the repo in order to track additions and changes.
Impress Me I am looking forward to an inrush of new datasets, along with some blog posts and apps that show how to to use the data in powerful and interesting ways. Let me know what you come up with.
A simple Raspberry Pi based project using TCS3200 Color Sensor. The project demonstrates how to interface a Color Sensor (like TCS3200) with Raspberry Pi and implement a simple Color Detector using Raspberry Pi.
What is a TCS3200 colour sensor?
Colour sensors sense reflected light from nearby objects. The bright light of the TCS3200’s on-board white LEDs hits an object’s surface and is reflected back. The sensor has an 8×8 array of photodiodes, which are covered by either a red, blue, green, or clear filter. The type of filter determines what colour a diode can detect. Then the overall colour of an object is determined by how much light of each colour it reflects. (For example, a red object reflects mostly red light.)
As Electronics Hub explains:
TCS3200 is one of the easily available colour sensors that students and hobbyists can work on. It is basically a light-to-frequency converter, i.e. based on colour and intensity of the light falling on it, the frequency of its output signal varies.
I’ll save you a physics lesson here, but you can find a detailed explanation of colour sensing and the TCS3200 on the Electronics Hub blog.
Raspberry Pi colour sensor
The TCS3200 colour sensor is connected to several of the onboard General Purpose Input Output (GPIO) pins on the Raspberry Pi.
These connections allow the Raspberry Pi 3 to run one of two Python scripts that Electronics Hub has written for the project. The first displays the RAW RGB values read by the sensor. The second detects the primary colours red, green, and blue, and it can be expanded for more colours with the help of the first script.
Electronic Hub’s complete build uses a breadboard for simply prototyping
Use it in your projects
This colour sensing setup is a simple means of adding a new dimension to your builds. Why not build a candy-sorting robot that organises your favourite sweets by colour? Or add colour sensing to your line-following buggy to allow for multiple path options!
If your Raspberry Pi project uses colour sensing, we’d love to see it, so be sure to share it in the comments!
AWS CloudHSM provides fully managed, single-tenant hardware security modules (HSMs) in the AWS cloud. A CloudHSM cluster contains either one or multiple HSMs. Multiple HSMs support higher throughput levels for cryptographic operations and provide redundancy. For clusters with multiple HSMs, the CloudHSM service supports server-side automated synchronization of keys and policies. Users, however, are synchronized from the client-side and the synchronization is driven by configuration files which must be refreshed when the cluster size changes. If you do not refresh the configuration files, your CloudHSM user configurations could become unsynchronized and affect the ability of your CloudHSM cluster to provide consistent support of cryptographic information.
In this blog post, I’ll provide a general overview of a CloudHSM architecture, discuss the cluster synchronization process, build a CloudHSM environment, show how the cluster users can become unsynchronized, and then restore user synchronization to bring your cluster back to a consistent state to meet your needs for consistency and redundancy.
CloudHSM Architectural Overview
When you provision an HSM instance in CloudHSM, the HSM instance provides an elastic network interface (ENI) in yourAmazon VPC while the HSM itself resides in a separate VPC managed by AWS CloudHSM. Your applications use the CloudHSM cluster ID to add or remove HSMs from the cluster and the ENI(s) of the HSM instance(s) to access the HSM instances.
You configure your cluster and its HSM instances using CloudHSM client software you deploy on Amazon EC2 instances in your VPC. You only need one such EC2 instance to manage a CloudHSM cluster, but it’s common to deploy additional EC2 instances in other availability zones to provide for client redundancy. Your applications communicate with the HSM instances using the client daemon. You manage and configure the cluster with command line tools including cloudhsm_mgmt_util, key_mgmt_util, and configure. An example of a CloudHSM architecture appears below.
Figure 1: A 3-Node CloudHSM architecture
The diagram shows a three-node CloudHSM cluster deployed in the us-west-2 (Oregon) region with three Amazon EC2 instances with the CloudHSM software. The client in Availability Zone 2 is communicating with the cluster through the elastic network interfaces in each availability zone.
CloudHSM Synchronization Process
Having discussed the architecture of AWS CloudHSM, let’s turn our attention to the matter of cluster synchronization. There are three events that require synchronization: cluster expansion, key management operations, and user management operations. Let’s look at each of these in more detail.
When you add an HSM to an existing cluster, AWS CloudHSM clones all users, keys, and policies from another HSM in the cluster. No additional steps are required on your part.
Key Management Operations
Key management with the key_mgmt_util tool uses the CloudHSM client to communicate with the HSM cluster. Additionally, a fallback, HSM-based synchronization protocol keeps keys in sync.
You perform user management tasks, such as adding users or changing passwords, using the cloudhsm_mgmt_util tool. This tool communicates directly with the HSMs, bypassing the client daemon. cloudhsm_mgmt_util uses its own configuration files to determine the HSMs that it should connect to within the cluster. These configuration files aren’t updated dynamically when HSM instances are added. To prevent user synchronization errors, you must update the configuration files before running cloudhsm_mgmt_util. You must also not add new HSM instances to the cluster while you’re using the tool. This helps ensure that no HSM instances are accidentally left out of user updates that would in turn result in user synchronization problems.
Again, these safeguards are only necessary when using cloudhsm_mgmt_util. For all other applications and utilities using CloudHSM, the client daemon automatically reconfigures itself as you add and remove HSM instances from your cluster. In the remainder of this post, I will build a CloudHSM infrastructure as shown in the above diagram. I’ll then show you how users on your CloudHSM instances can become unsynchronized, and how to restore proper synchronization.
Prerequisites and Assumptions
You’ll need to have an AWS account that allows you to provision Amazon VPCs, Amazon EC2 instances, and CloudHSMs.
I’ll use the us-west-2 (Oregon) region, but you can use any region that offers CloudHSM.
You’ll need an Amazon EC2 key pair in the region.
You should have a working knowledge of the services I’ve mentioned.
Important: You’ll incur charges for the resources used in this example. You can find the cost of each service on that service’s pricing page.
Building a CloudHSM Infrastructure
Create an Amazon VPC with subnets in the us-west-2a, us-west-2b, and us-east-2c availability zones. I’ll use the Amazon VPC Architecture Quick Start, which is an AWS CloudFormation template that will do this on your behalf. Make sure you select the correct region after you load the Quick Start. Select the following parameters:
us-west-2a, us-west-2b, us-west-2c
Number of Availability Zones
Create private subnets
Create additional private subnets with dedicated network ACLs
Key pair name
The name of your Amazon EC2 key pair
Accept the default values for all other parameters.
Follow these instructions to create a CloudHSM cluster in your new VPC in the us-west-2a, us-west-2b and us-west-2c availability zones. Note that the cluster will not have any HSMs after it’s created.
Follow these instructions to initialize the cluster with an HSM in the us-west-2a availability zone. After the cluster is initialized, note the ENI IP address from the cluster details section in the console as shown here:
Add the IP of the EC2 instance that you identified in step 4 to the security group you identified in step 3.
Activate the cluster. The activation instructions will guide you through connecting to the EC2 instance you launched in step 4. Remain logged into the EC2 instance following the activation of the cluster for the steps below.
While you are still logged into the EC2 instance you just launched, follow the steps below to add a crypto user named example_user to the cluster:
Ensure the CloudHSM daemon is stopped:$ sudo stop cloudhsm-client
Configure the IP address of the initial HSM using the ENI IP address from step 3:$ sudo /opt/cloudhsm/bin/configure –a 10.0.129.209
Note: the configure tool updates two configuration files: one for the CloudHSM client, and the other for the cloudhsm_mgmt_util program that is used to administer users.
Start the CloudHSM client:$ sudo start cloudhsm-client
Ensure the cloudhsm_mgmt_util configuration file is up to date. We need to do this to ensure cloudhsm_mgmt_util is aware of all the HSM instances in the cluster:$ sudo /opt/cloudhsm/bin/configure –m
Connect to the HSM instances, enable end-to-end encryption, and log in to the HSM instances. Enabling end-to-end encryption encrypts the communication between cloudhsm_mgmt_util and the HSM to prevent interception of sensitive information such as passwords:$ /opt/cloudhsm/bin/cloudhsm_mgmt_util /opt/cloudhsm/etc/cloudhsm_mgmt_util.cfg
aws-cloudhsm> loginHSM CO admin
Figure 4: Connecting to a Single CloudHSM
Note: The connection or log in is automatically executed on every HSM instance that cloudhsm_mgmt_util is aware of. Note also that for each of the commands that you enter, the cloudhsm_mgmt_util program identifies the IP address of the HSM to which it is communicating.
Add the user example_user and then confirm the addition by listing the users in the HSM:aws-cloudhsm> createUser CU example_user yourpassword
Use the quit command to log out and exit the program:aws-cloudhsm> quit
Now that we’ve added a user to the CloudHSM, let’s add a key so we can see how users and keys are synchronized as the cluster changes.
Start the key_mgmt_util program:$ /opt/cloudhsm/bin/key_mgmt_util
Log in to the HSM:Command: loginHSM –u CU –s example_user
Figure 7: Connecting to the 2-node CloudHSM cluster
Note that cloudhsm_mgmt_utilcloudhsm_mgmt_util now sends commands to both of the HSMs in the cluster. You can see the same thing when we list the users in the cluster.
Figure 8: Showing proper user synchronization across two CloudHSMs
Now, use key_mgmt_util to examine the keys:Command: findKey
Figure 9: Showing that keys are properly synchronized across a 2-node CloudHSM cluster
This command confirms that when we added the second HSM, CloudHSM used cluster-initiated synchronization to load the users and keys into the new HSM.
The CloudHSM Cluster Users Become Unsynchronized
Start cloudhsm_mgmt_util and enable end-to-end encryption:$ /opt/cloudhsm/bin/cloudhsm_mgmt_util /opt/cloudhsm/etc/cloudhsm_mgmt_util.cfg
Figure 10: Connecting to the 2-node CloudHSM cluster
While cloudhsm_mgmt_util is left running, add a third HSM in us-west-2c through the console and note the ENI IP address, as shown here:
Figure 11: Connecting to the 2-node CloudHSM cluster
Going back to cloudhsm_mgmt_util, let’s add a user named newest_user to our cluster. Note that we have not exited cloudhsm_mgmt_util and refreshed its configuration file. So it’s still connected only to the first two HSM instances.aws-cloudhsm> enable_e2e
aws-cloudhsm> loginHSM CO admin yourpassword
aws-cloudhsm> createUser CU newest_user yourpassword
Figure 12: Adding a User to only two nodes of a 3-node CloudHSM Cluster and breaking synchronization
The cloudhsm_mgmt_util command adds the user to the two HSMs it already knows about and had connected to. It doesn’t communicate with the newly added HSM.
Let’s fix this by exiting cloudhsm_mgmt_util. Refresh the configuration, and then run the management utility again.$sudo stop cloudhsm-client
You can now see cloudhsm_mgmt_util is communicating with all of the cluster nodes.
Figure 13: Connecting to a 3-node CloudHSM cluster
Let’s see what happens when we list the users:aws-cloudhsm> listUsers
Figure 14: Showing that users are now unsynchronized
You can see from the results that one of the HSMs (server 1) is missing the user named newest_user. The reason this happened is that cloudhsm_mgmt_util was unaware of the HSM instance that was added while it was running (recall that cloudhsm_mgmt_util doesn’t use the cloudhsm_client daemon and, therefore, doesn’t get automatic cluster configuration updates).
Restoring User Synchronization to the CloudHSM Cluster
We now want to add the user newest_user to the single HSM (server 1) that is out of sync. Normally, cloudhsm_mgmt_util works in cluster mode and applies your commands to all HSMs in the cluster. Since we want to work on a single HSM, we’re going to enter the server command to tell cloudhsm_mgmt_util to work in server mode and apply our commands just to that one HSM.
In the server command below, we specify the number of the HSM that we want to change based on the figure above. In the createUser command, you must use the same password that you used in step 3 (in the section titled “The CloudHSM Cluster Users Become Unsynchronized”) on the other HSMs in the cluster so that all HSMs in the cluster have identical user names and passwords. After we make this change, we use the exit command to transition from server mode back to cluster mode.aws-cloudhsm> server 1
server1> createUser CU newest_user yourpassword
Figure 15: Adding a user to a single-node of a 3-node CloudHSM cluster
Now that we have transitioned back to cluster mode, let’s confirm that the HSM user tables are now synchronized by listing the users:aws-cloudhsm> listUsers
Figure 16: Showing that users are now synchronized across the 3-node CloudHSM cluster
Let’s take a look at the keys using key_mgmt_util:Command: loginHSM –u CU –s example_user –p yourpassword
Figure 17: Showing that keys continued to be synchronized across a 3-node CloudHSM Cluster
You can see that CloudHSM kept the keys in sync because key synchronization is cluster-initiated. No additional actions are required on our part.
AWS CloudHSM provides the ability to create scalable clusters of HSM instances to support the high volumes of cryptographic operations and provide resiliency by supporting multiple availability zones. As mentioned, it’s important to be aware of the various modes of synchronization used in CloudHSM so that each HSM can provide consistent service. In particular, users are synchronized only by the client. Since cloudhsm_mgmt_util doesn’t rely on the client daemon to talk to HSM instances in your cluster, it doesn’t automatically update its configuration. By following the steps above and refreshing the configuration information before changing users or passwords, CloudHSM will keep users and passwords synchronized within the cluster and provide consistent responses to cryptographic operations if the level of redundancy within the HSM cluster changes.
If you have feedback about this blog post, submit comments in the Comments section below. If you have questions about this blog post, start a new thread on the Amazon CloudHSM forum or contact AWS Support.
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Before Easter, we asked you to tell us your questions for a live Q & A with Raspberry Pi Trading CEO and Raspberry Pi creator Eben Upton. The variety of questions and comments you sent was wonderful, and while we couldn’t get to them all, we picked a handful of the most common to grill him on.
You can watch the video below — though due to this being the first pancake of our live Q&A videos, the sound is a bit iffy — or read Eben’s answers to the first five questions today. We’ll follow up with the rest in the next few weeks!
Get your questions to us now using #AskRaspberryPi on Twitter
Any plans for 64-bit Raspbian?
Raspbian is effectively 32-bit Debian built for the ARMv6 instruction-set architecture supported by the ARM11 processor in the first-generation Raspberry Pi. So maybe the question should be: “Would we release a version of our operating environment that was built on top of 64-bit ARM Debian?”
And the answer is: “Not yet.”
When we released the Raspberry Pi 3 Model B+, we released an operating system image on the same day; the wonderful thing about that image is that it runs on every Raspberry Pi ever made. It even runs on the alpha boards from way back in 2011.
That deep backwards compatibility is really important for us, in large part because we don’t want to orphan our customers. If someone spent $35 on an older-model Raspberry Pi five or six years ago, they still spent $35, so it would be wrong for us to throw them under the bus.
So, if we were going to do a 64-bit version, we’d want to keep doing the 32-bit version, and then that would mean our efforts would be split across the two versions; and remember, we’re still a very small engineering team. Never say never, but it would be a big step for us.
For people wanting a 64-bit operating system, there are plenty of good third-party images out there, including SUSE Linux Enterprise Server.
Given that the 3B+ includes 5GHz wireless and Power over Ethernet (PoE) support, why would manufacturers continue to use the Compute Module?
Very large numbers of people are using the bigger product in an industrial context, and it’s well engineered for that: it has module certification, wireless on board, and now PoE support. But there are use cases that can’t accommodate this form factor. For example, NEC displays: we’ve had this great relationship with NEC for a couple of years now where a lot of their displays have a socket in the back that you can put a Compute Module into. That wouldn’t work with the 3B+ form factor.
An NEC display with a Raspberry Pi Compute Module
What are some industrial uses/products Raspberry is used with?
The NEC displays are a good example of the broader trend of using Raspberry Pi in digital signage.
A Raspberry Pi running the wait time signage at The Wizarding World of Harry Potter, Universal Studios. Image c/o thelonelyredditor1
If you see a monitor at a station, or an airport, or a recording studio, and you look behind it, it’s amazing how often you’ll find a Raspberry Pi sitting there. The original Raspberry Pi was particularly strong for multimedia use cases, so we saw uptake in signage very early on.
Los Alamos Raspberry Pi supercomputer
Another great example is the Los Alamos National Laboratory building supercomputers out of Raspberry Pis. Many high-end supercomputers now are built using white-box hardware — just regular PCs connected together using some networking fabric — and a collection of Raspberry Pi units can serve as a scale model of that. The Raspberry Pi has less processing power, less memory, and less networking bandwidth than the PC, but it has a balanced amount of each. So if you don’t want to let your apprentice supercomputer engineers loose on your expensive supercomputer, a cluster of Raspberry Pis is a good alternative.
Why is there no power button on the Raspberry Pi?
“Once you start, where do you stop?” is a question we ask ourselves a lot.
There are a whole bunch of useful things that we haven’t included in the Raspberry Pi by default. We don’t have a power button, we don’t have a real-time clock, and we don’t have an analogue-to-digital converter — those are probably the three most common requests. And the issue with them is that they each cost a bit of money, they’re each only useful to a minority of users, and even that minority often can’t agree on exactly what they want. Some people would like a power button that is literally a physical analogue switch between the 5V input and the rest of the board, while others would like something a bit more like a PC power button, which is partway between a physical switch and a ‘shutdown’ button. There’s no consensus about what sort of power button we should add.
So the answer is: accessories. By leaving a feature off the board, we’re not taxing the majority of people who don’t want the feature. And of course, we create an opportunity for other companies in the ecosystem to create and sell accessories to those people who do want them.
We have this neat way of figuring out what features to include by default: we divide through the fraction of people who want it. If you have a 20 cent component that’s going to be used by a fifth of people, we treat that as if it’s a $1 component. And it has to fight its way against the $1 components that will be used by almost everybody.
Do you think that Raspberry Pi is the future of the Internet of Things?
Absolutely, Raspberry Pi is the future of the Internet of Things!
In practice, most of the viable early IoT use cases are in the commercial and industrial spaces rather than the consumer space. Maybe in ten years’ time, IoT will be about putting 10-cent chips into light switches, but right now there’s so much money to be saved by putting automation into factories that you don’t need 10-cent components to address the market. Last year, roughly 2 million $35 Raspberry Pi units went into commercial and industrial applications, and many of those are what you’d call IoT applications.
So I think we’re the future of a particular slice of IoT. And we have ten years to get our price point down to 10 cents 🙂
Writing programs that create things in Minecraft is not only a great way to learn how to code, but it also means that you have a program that you can run again and again to make as many copies of your Minecraft design as you want. You never need to worry about your creation being destroyed by your brother or sister ever again — simply rerun your program and get it back! Whilst it might take a little longer to write the program than to build one house, once it’s finished you can build as many houses as you want.
Co-ordinates in Minecraft
Let’s start with a review of the coordinate system that Minecraft uses to know where to place blocks. If you are already familiar with this, you can skip to the next section. Otherwise, read on.
Plan view of our house design
Minecraft shows us a three-dimensional (3D) view of the world. Imagine that the room you are in is the Minecraft world and you want to describe your location within that room. You can do so with three numbers, as follows:
How far across the room are you? As you move from side to side, you change this number. We can consider this value to be our X coordinate.
How high off the ground are you? If you are upstairs, or if you jump, this value increases. We can consider this value to be our Y coordinate.
How far into the room are you? As you walk forwards or backwards, you change this number. We can consider this value to be our Z coordinate.
You might have done graphs in school with X going across the page and Y going up the page. Coordinates in Minecraft are very similar, except that we have an extra value, Z, for our third dimension. Don’t worry if this still seems a little confusing: once we start to build our house, you will see how these three dimensions work in Minecraft.
Designing our house
It is a good idea to start with a rough design for our house. This will help us to work out the values for the coordinates when we are adding doors and windows to our house. You don’t have to plan every detail of your house right away. It is always fun to enhance it once you have got the basic design written. The image above shows the plan view of the house design that we will be creating in this tutorial. Note that because this is a plan view, it only shows the X and Z co-ordinates; we can’t see how high anything is. Hopefully, you can imagine the house extending up from the screen.
We will build our house close to where the Minecraft player is standing. This a good idea when creating something in Minecraft with Python, as it saves us from having to walk around the Minecraft world to try to find our creation.
Starting our program
Type in the code as you work through this tutorial. You can use any editor you like; we would suggest either Python 3 (IDLE) or Thonny Python IDE, both of which you can find on the Raspberry Pi menu under Programming. Start by selecting the File menu and creating a new file. Save the file with a name of your choice; it must end with .py so that the Raspberry Pi knows that it is a Python program.
It is important to enter the code exactly as it is shown in the listing. Pay particular attention to both the spelling and capitalisation (upper- or lower-case letters) used. You may find that when you run your program the first time, it doesn’t work. This is very common and just means there’s a small error somewhere. The error message will give you a clue about where the error is.
It is good practice to start all of your Python programs with the first line shown in our listing. All other lines that start with a # are comments. These are ignored by Python, but they are a good way to remind us what the program is doing.
The two lines starting with from tell Python about the Minecraft API; this is a code library that our program will be using to talk to Minecraft. The line starting mc = creates a connection between our Python program and the game. Then we get the player’s location broken down into three variables: x, y, and z.
Building the shell of our house
To help us build our house, we define three variables that specify its width, height, and depth. Defining these variables makes it easy for us to change the size of our house later; it also makes the code easier to understand when we are setting the co-ordinates of the Minecraft bricks. For now, we suggest that you use the same values that we have; you can go back and change them once the house is complete and you want to alter its design.
It’s now time to start placing some bricks. We create the shell of our house with just two lines of code! These lines of code each use the setBlocks command to create a complete block of bricks. This function takes the following arguments:
setBlocks(x1, y1, z1, x2, y2, z2, block-id, data)
x1, y1, and z1 are the coordinates of one corner of the block of bricks that we want to create; x1, y1, and z1 are the coordinates of the other corner. The block-id is the type of block that we want to use. Some blocks require another value called data; we will see this being used later, but you can ignore it for now.
We have to work out the values that we need to use in place of x1, y1, z1, x1, y1, z1 for our walls. Note that what we want is a larger outer block made of bricks and that is filled with a slightly smaller block of air blocks. Yes, in Minecraft even air is actually just another type of block.
Once you have typed in the two lines that create the shell of your house, you almost ready to run your program. Before doing so, you must have Minecraft running and displaying the contents of your world. Do not have a world loaded with things that you have created, as they may get destroyed by the house that we are building. Go to a clear area in the Minecraft world before running the program. When you run your program, check for any errors in the ‘console’ window and fix them, repeatedly running the code again until you’ve corrected all the errors.
You should see a block of bricks now, as shown above. You may have to turn the player around in the Minecraft world before you can see your house.
Adding the floor and door
Now, let’s make our house a bit more interesting! Add the lines for the floor and door. Note that the floor extends beyond the boundary of the wall of the house; can you see how we achieve this?
Hint: look closely at how we calculate the x and z attributes as compared to when we created the house shell above. Also note that we use a value of y-1 to create the floor below our feet.
Minecraft doors are two blocks high, so we have to create them in two parts. This is where we have to use the data argument. A value of 0 is used for the lower half of the door, and a value of 8 is used for the upper half (the part with the windows in it). These values will create an open door. If we add 4 to each of these values, a closed door will be created.
Before you run your program again, move to a new location in Minecraft to build the house away from the previous one. Then run it to check that the floor and door are created; you will need to fix any errors again. Even if your program runs without errors, check that the floor and door are positioned correctly. If they aren’t, then you will need to check the arguments so setBlock and setBlocks are exactly as shown in the listing.
Hopefully you will agree that your house is beginning to take shape! Now let’s add some windows. Looking at the plan for our house, we can see that there is a window on each side; see if you can follow along. Add the four lines of code, one for each window.
Now you can move to yet another location and run the program again; you should have a window on each side of the house. Our house is starting to look pretty good!
Adding a roof
The final stage is to add a roof to the house. To do this we are going to use wooden stairs. We will do this inside a loop so that if you change the width of your house, more layers are added to the roof. Enter the rest of the code. Be careful with the indentation: I recommend using spaces and avoiding the use of tabs. After the if statement, you need to indent the code even further. Each indentation level needs four spaces, so below the line with if on it, you will need eight spaces.
Since some of these code lines are lengthy and indented a lot, you may well find that the text wraps around as you reach the right-hand side of your editor window — don’t worry about this. You will have to be careful to get those indents right, however.
Now move somewhere new in your world and run the complete program. Iron out any last bugs, then admire your house! Does it look how you expect? Can you make it better?
Customising your house
Now you can start to customise your house. It is a good idea to use Save As in the menu to save a new version of your program. Then you can keep different designs, or refer back to your previous program if you get to a point where you don’t understand why your new one doesn’t work.
Consider these changes:
Change the size of your house. Are you able also to move the door and windows so they stay in proportion?
Change the materials used for the house. An ice house placed in an area of snow would look really cool!
Add a back door to your house. Or make the front door a double-width door!
We hope that you have enjoyed writing this program to build a house. Now you can easily add a house to your Minecraft world whenever you want to by simply running this program.
Thanks to Raja Mani, AWS Solutions Architect, for this great blog.
In this blog post, I’ll walk you through the steps for setting up continuous replication of an AWS CodeCommit repository from one AWS region to another AWS region using a serverless architecture. CodeCommit is a fully-managed, highly scalable source control service that stores anything from source code to binaries. It works seamlessly with your existing Git tools and eliminates the need to operate your own source control system. Replicating an AWS CodeCommit repository from one AWS region to another AWS region enables you to achieve lower latency pulls for global developers. This same approach can also be used to automatically back up repositories currently hosted on other services (for example, GitHub or BitBucket) to AWS CodeCommit.
This solution uses AWS Lambda and AWS Fargate for continuous replication. Benefits of this approach include:
The replication process can be easily setup to trigger based on events, such as commits made to the repository.
Setting up a serverless architecture means you don’t need to provision, maintain, or administer servers.
Note: AWS Fargate has a limitation of 10 GB for storage and is available in US East (N. Virginia) region. A similar solution that uses Amazon EC2 instances to replicate the repositories on a schedule was published in a previous blog and can be used if your repository does not meet these conditions.
Replication using Fargate
As you follow this blog post, you’ll set up an architecture that looks like this:
Any change in the AWS CodeCommit repository will trigger a Lambda function. The Lambda function will call the Fargate task that replicates the repository using a Git command line tool.
Let us assume a user wants to replicate a repository (Source) from US East (N. Virginia/us-east-1) region to a repository (Destination) in US West (Oregon/us-west-2) region. I’ll walk you through the steps for it:
Create an AWS Service IAM role for Amazon EC2 that has permission for both source and destination repositories, IAM CreateRole, AttachRolePolicy and Amazon ECR privileges. Here is the EC2 role policy I used:
You need a Docker environment to build this solution. You can launch an EC2 instance and install Docker (or) you can use AWS Cloud9 that comes with Docker and Git preinstalled. I used an EC2 instance and installed Docker in it. Use the IAM role created in the previous step when creating the EC2 instance. I am going to refer this environment as “Docker Environment” in the following steps.
You need to install the AWS CLI on the Docker environment. For AWS CLI installation, refer this page.
You need to install Git, including a Git command line on the Docker environment.
Step 1: Create the Docker image
To create the Docker image, first it needs a Dockerfile. A Dockerfile is a manifest that describes the base image to use for your Docker image and what you want installed and running on it. For more information about Dockerfiles, go to the Dockerfile Reference.
1. Choose a directory in the Docker environment and perform the following steps in that directory. I used /home/ec2-user directory to perform the following steps.
2. Clone the AWS CodeCommit repository in the Docker environment. Open the terminal to the Docker environment and run the following commands to clone your source AWS CodeCommit repository (I ran the commands from /home/ec2-user directory):
Note: Change the URL marked in red to your source and destination repository URL.
3. Create a file called Dockerfile (case sensitive) with the following content (I created it in /home/ec2-user directory):
# Pull the Amazon Linux latest base image
#Install aws-cli and git command line tools
RUN yum -y install unzip aws-cli
RUN yum -y install git
RUN mkdir LocalRepository
#Copy Cloned CodeCommit repository to Docker container
COPY ./LocalRepository /home/ec2-user/LocalRepository
#Copy shell script that does the replication
COPY ./repl_repository.bash /home/ec2-user/LocalRepository
RUN chmod ugo+rwx /home/ec2-user/LocalRepository/repl_repository.bash
#Call this script when Docker starts the container
4. Copy the following shell script into a file called repl_repository.bash to the DockerFile directory location in the Docker environment (I created it in /home/ec2-user directory)
6. Verify whether the replication is working by running the repl_repository.bash script from the LocalRepository directory. Go to LocalRepository directory and run this command: . ../repl_repository.bash If it is successful, you will get the “Everything up-to-date” at the last line of the result like this:
$ . ../repl_repository.bash
Step 2: Build the Docker Image
1. Build the Docker image by running this command from the directory where you created the DockerFile in the Docker environment in the previous step (I ran it from /home/ec2-user directory):
$ docker build . –t ccrepl
Output: It installs various packages and set environment variables as part of steps 1 to 3 from the Dockerfile. The steps 4 to 11 from the Dockerfile should produce an output similar to the following:
2. Create a role called AccessRoleForCCfromFG using the following command in the DockerEnvironment:
$ aws iam create-role --role-name AccessRoleForCCfromFG --assume-role-policy-document file://trustpolicyforecs.json
3. Assign CodeCommit service full access to the above role using the following command in the DockerEnvironment:
$ aws iam attach-role-policy --policy-arn arn:aws:iam::aws:policy/AWSCodeCommitFullAccess --role-name AccessRoleForCCfromFG
4. In the Amazon ECS Console, choose Repositories and select the ccrepl repository that was created in the previous step. Copy the Repository URI.
5. In the Amazon ECS Console, choose Task Definitions and click Create New Task Definition.
6. Select launch type compatibility as FARGATE and click Next Step.
7. In the create task definition screen, do the following:
In Task Definition Name, type ccrepl
In Task Role, choose AccessRoleForCCfromFG
In Task Memory, choose 2GB
In Task CPU, choose 1 vCPU
Click Add Container under Container Definitions in the same screen. In the Add Container screen, do the following:
Enter Container name as ccreplcont
Enter Image URL copied from step 4
Enter Memory Limits as 128 and click Add.
Note: Select TaskExecutionRole as “ecsTaskExecutionRole” if it already exists. If not, select create new role and it will create “ecsTaskExecutionRole” for you.
8. Click the Create button in the task definition screen to create the task. It will successfully create the task, execution role and AWS CloudWatch Log groups.
9. In the Amazon ECS Console, click Clusters and create cluster. Select template as “Networking only, Powered by AWS Fargate” and click next step.
10. Enter cluster name as ccreplcluster and click create.
Step 5: Create the Lambda Function
In this section, I used Amazon Elastic Container Service (ECS) run task API from Lambda to invoke the Fargate task.
1. In the IAM Console, create a new role called ECSLambdaRole with the permissions to AWS CodeCommit, Amazon ECS as well as pass roles privileges needed to run the ECS task. Your statement should look similar to the following (replace <your account id>):
1. In the Lambda Console, click FargateTaskExecutionFunc under functions.
2. Under Add triggers in the Designer, select CodeCommit
3. In the Configure triggers screen, do the following:
Enter Repository name as Source (your source repository name)
Enter trigger name as LambdaTrigger
Leave the Events as “All repository events”
Leave the Branch names as “All branches”
Click Add button
Click Save button to save the changes
Step 6: Verification
To test the application, make a commit and push the changes to the source repository in AWS CodeCommit. That should automatically trigger the Lambda function and replicate the changes in the destination repository. You can verify this by checking CloudWatch Logs for Lambda and ECS, or simply going to the destination repository and verifying the change appears.
Congratulations! You have successfully configured repository replication of an AWS CodeCommit repository using AWS Lambda and AWS Fargate. You can use this technique in a deployment pipeline. You can also tweak the trigger configuration in AWS CodeCommit to call the Lambda function in response to any supported trigger event in AWS CodeCommit.
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