Building Simpler Genomics Workflows on AWS Step Functions

Post Syndicated from Christie Gifrin original https://aws.amazon.com/blogs/compute/building-simpler-genomics-workflows-on-aws-step-functions/

This post is courtesy of Ryan Ulaszek, AWS Genomics Partner Solutions Architect and Aaron Friedman, AWS Healthcare and Life Sciences Partner Solutions Architect

In 2017, we published a four part blog series on how to build a genomics workflow on AWS. In part 1, we introduced a general architecture highlighting three common layers: job, batch and workflow.  In part 2, we described building the job layer with Docker and Amazon Elastic Container Registry (Amazon ECR).  In part 3, we tackled the batch layer and built a batch engine using AWS Batch.  In part 4, we built out the workflow layer using AWS Step Functions and AWS Lambda.

Since then, we’ve worked with many AWS customers and APN partners to implement this solution in genomics as well as in other workloads-of-interest. Today, we wanted to highlight a new feature in Step Functions that simplifies how customers and partners can build high-throughput genomics workflows on AWS.

Step Functions now supports native integration with AWS Batch, which simplifies how you can create an AWS Batch state that submits an asynchronous job and waits for that job to finish.

Before, you needed to build a state machine building block that submitted a job to AWS Batch, and then polled and checked its execution. Now, you can just submit the job to AWS Batch using the new AWS Batch task type.  Step Functions waits to proceed until the job is completed. This reduces the complexity of your state machine and makes it easier to build a genomics workflow with asynchronous AWS Batch steps.

The new integrations include support for the following API actions:

  • AWS Batch SubmitJob
  • Amazon SNS Publish
  • Amazon SQS SendMessage
  • Amazon ECS RunTask
  • AWS Fargate RunTask
  • Amazon DynamoDB
    • PutItem
    • GetItem
    • UpdateItem
    • DeleteItem
  • Amazon SageMaker
    • CreateTrainingJob
    • CreateTransformJob
  • AWS Glue
    • StartJobRun

You can also pass parameters to the service API.  To use the new integrations, the role that you assume when running a state machine needs to have the appropriate permissions.  For more information, see the AWS Step Functions Developer Guide.

Using a job status poller

In our 2017 post series, we created a job poller “pattern” with two separate Lambda functions. When the job finishes, the state machine proceeds to the next step and operates according to the necessary business logic.  This is a useful pattern to manage asynchronous jobs when a direct integration is unavailable.

The steps in this building block state machine are as follows:

  1. A job is submitted through a Lambda function.
  2. The state machine queries the AWS Batch API for the job status in another Lambda function.
  3. The job status is checked to see if the job has completed.  If the job status equals SUCCESS, the final job status is logged. If the job status equals FAILED, the execution of the state machine ends. In all other cases, wait 30 seconds and go back to Step 2.

Both of the Submit Job and Get Job Lambda functions are available as example Lambda functions in the console.  The job status poller is available in the Step Functions console as a sample project.

Here is the JSON representing this state machine.

{
  "Comment": "A simple example that submits a job to AWS Batch",
  "StartAt": "SubmitJob",
  "States": {
    "SubmitJob": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:<account-id>::function:batchSubmitJob",
      "Next": "GetJobStatus"
    },
    "GetJobStatus": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:<account-id>:function:batchGetJobStatus",
      "Next": "CheckJobStatus",
      "InputPath": "$",
      "ResultPath": "$.status"
    },
    "CheckJobStatus": {
      "Type": "Choice",
      "Choices": [
        {
          "Variable": "$.status",
          "StringEquals": "FAILED",
          "End": true
        },
        {
          "Variable": "$.status",
          "StringEquals": "SUCCEEDED",
          "Next": "GetFinalJobStatus"
        }
      ],
      "Default": "Wait30Seconds"
    },
    "Wait30Seconds": {
      "Type": "Wait",
      "Seconds": 30,
      "Next": "GetJobStatus"
    },
    "GetFinalJobStatus": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:<account-id>:function:batchGetJobStatus",
      "End": true
    }
  }
}

With Step Functions Service Integrations

With Step Functions service integrations, it is now simpler to submit and wait for an AWS Batch job, or any other supported service.

The following code block is the JSON representing the new state machine for an asynchronous batch job. If you are familiar with the AWS Batch SubmitJob API action, you may notice that the parameters are consistent with what you would see in that API call. You can also use the optional AWS Batch parameters in addition to JobDefinition, JobName, and JobQueue.

{
 "StartAt": "RunBatchJob",
 "States": {
     "RunIsaacJob":{
     "Type":"Task",
     "Resource":"arn:aws:states:::batch:submitJob.sync",
     "Parameters":{
        "JobDefinition":"Isaac",
        "JobName.$":"$.isaac.JobName",
        "JobQueue":"HighPriority",
        "Parameters.$": "$.isaac"
     },
     "TimeoutSeconds": 900,
     "HeartbeatSeconds": 60,
     "Next":"Parallel",
     "InputPath":"$",
     "ResultPath":"$.status",
     "Retry" : [
        {
          "ErrorEquals": [ "States.Timeout" ],
          "IntervalSeconds": 3,
          "MaxAttempts": 2,
          "BackoffRate": 1.5
        }
     ]
  }
}

Here is an example of the workflow input JSON.  Pass all of the container parameters that were being constructed in the submit job Lambda function.

{
  "isaac": {
    "WorkingDir": "/scratch",
    "JobName": "isaac-1",
    "FastQ1S3Path": "s3://aws-batch-genomics-resources/fastq/SRR1919605_1.fastq.gz",
    "BAMS3FolderPath": "s3://aws-batch-genomics-resources/fastq/SRR1919605_2.fastq.gz",
    "FastQ2S3Path": "s3://bccn-genome-data/fastq/NIST7035_R2_trimmed.fastq.gz",
    "ReferenceS3Path": "s3://aws-batch-genomics-resources/reference/isaac/"
  }
}

When you deploy the job definition, add the command attribute that was previously being constructed in the Lambda function launching the AWS Batch job.

IsaacJobDefinition:
    Type: AWS::Batch::JobDefinition
    Properties:
      JobDefinitionName: "Isaac"
      Type: container
      RetryStrategy:
        Attempts: 1
      Parameters:
        BAMS3FolderPath: !Sub "s3://${JobResultsBucket}/NA12878_states_1/bam"
        FastQ1S3Path: "s3://aws-batch-genomics-resources/fastq/SRR1919605_1.fastq.gz"
        FastQ2S3Path: "s3://aws-batch-genomics-resources/fastq/SRR1919605_2.fastq.gz"
        ReferenceS3Path: "s3://aws-batch-genomics-resources/reference/isaac/"
        WorkingDir: "/scratch"
      ContainerProperties:
        Image: "rulaszek/isaac"
        Vcpus: 32
        Memory: 80000
        JobRoleArn:
          Fn::ImportValue: !Sub "${RoleStackName}:ECSTaskRole"
        Command:
          - "--bam_s3_folder_path"
          - "Ref::BAMS3FolderPath"
          - "--fastq1_s3_path"
          - "Ref::FastQ1S3Path"
          - "--fastq2_s3_path"
          - "Ref::FastQ2S3Path"
          - "--reference_s3_path"
          - "Ref::ReferenceS3Path"
          - "--working_dir"
          - "Ref::WorkingDir"
        MountPoints:
          - ContainerPath: "/scratch"
            ReadOnly: false
            SourceVolume: docker_scratch
        Volumes:
          - Name: docker_scratch
            Host:
              SourcePath: "/docker_scratch"

The key-value parameters passed into the workflow are mapped using Parameters.$ to the values in the job definition using the keys.  Value substitutions do take place. The Docker run looks like the following:

docker run <isaac_container_uri> --bam_s3_folder_path s3://batch-genomics-pipeline-jobresultsbucket-1kzdu216m2b0k/NA12878_states_3/bam
                                 --fastq1_s3_path s3://aws-batch-genomics-resources/fastq/SRR1919605_1.fastq.gz
                                 --fastq2_s3_path s3://aws-batch-genomics-resources/fastq/SRR1919605_2.fastq.gz 
                                 --reference_s3_path s3://aws-batch-genomics-resources/reference/isaac/ 
                                 --working_dir /scratch

Genomics workflow: Before and after

Overall, connectors dramatically simplify your genomics workflow.  The following workflow is a simple genomics secondary analysis pipeline, which we highlighted in our original post series.

The first step aligns the sample against a reference genome.  When alignment is complete, variant calling and QA metrics are calculated in two parallel steps.  When variant calling is complete, variant annotation is performed.  Before, our genomics workflow looked like this:

Now it looks like this:

Here is the new workflow JSON:

{
   "Comment":"A simple genomics secondary-analysis workflow",
   "StartAt":"RunIsaacJob",
   "States":{
      "RunIsaacJob":{
         "Type":"Task",
         "Resource":"arn:aws:states:::batch:submitJob.sync",
         "Parameters":{
            "JobDefinition":"Isaac",
            "JobName.$":"$.isaac.JobName",
            "JobQueue":"HighPriority",
            "Parameters.$": "$.isaac"
         },
         "TimeoutSeconds": 900,
         "HeartbeatSeconds": 60,
         "Next":"Parallel",
         "InputPath":"$",
         "ResultPath":"$.status",
         "Retry" : [
            {
              "ErrorEquals": [ "States.Timeout" ],
              "IntervalSeconds": 3,
              "MaxAttempts": 2,
              "BackoffRate": 1.5
            }
         ]
      },
      "Parallel":{
         "Type":"Parallel",
         "Next":"FinalState",
         "Branches":[
            {
               "StartAt":"RunStrelkaJob",
               "States":{
                  "RunStrelkaJob":{
                     "Type":"Task",
                     "Resource":"arn:aws:states:::batch:submitJob.sync",
                     "Parameters":{
                        "JobDefinition":"Strelka",
                        "JobName.$":"$.strelka.JobName",
                        "JobQueue":"HighPriority",
                        "Parameters.$": "$.strelka"
                     },
                     "TimeoutSeconds": 900,
                     "HeartbeatSeconds": 60,
                     "Next":"RunSnpEffJob",
                     "InputPath":"$",
                     "ResultPath":"$.status",
                     "Retry" : [
                        {
                          "ErrorEquals": [ "States.Timeout" ],
                          "IntervalSeconds": 3,
                          "MaxAttempts": 2,
                          "BackoffRate": 1.5
                        }
                     ]
                  },
                  "RunSnpEffJob":{
                     "Type":"Task",
                     "Resource":"arn:aws:states:::batch:submitJob.sync",
                     "Parameters":{
                        "JobDefinition":"SNPEff",
                        "JobName.$":"$.snpeff.JobName",
                        "JobQueue":"HighPriority",
                        "Parameters.$": "$.snpeff"
                     },
                     "TimeoutSeconds": 900,
                     "HeartbeatSeconds": 60,
                     "Retry" : [
                        {
                          "ErrorEquals": [ "States.Timeout" ],
                          "IntervalSeconds": 3,
                          "MaxAttempts": 2,
                          "BackoffRate": 1.5
                        }
                     ],
                     "End":true
                  }
               }
            },
            {
               "StartAt":"RunSamtoolsStatsJob",
               "States":{
                  "RunSamtoolsStatsJob":{
                     "Type":"Task",
                     "Resource":"arn:aws:states:::batch:submitJob.sync",
                     "Parameters":{
                        "JobDefinition":"SamtoolsStats",
                        "JobName.$":"$.samtools.JobName",
                        "JobQueue":"HighPriority",
                        "Parameters.$": "$.samtools"
                     },
                     "TimeoutSeconds": 900,
                     "HeartbeatSeconds": 60,
                     "End":true,
                     "Retry" : [
                        {
                          "ErrorEquals": [ "States.Timeout" ],
                          "IntervalSeconds": 3,
                          "MaxAttempts": 2,
                          "BackoffRate": 1.5
                        }
                     ]
                  }
               }
            }
         ]
      },
      "FinalState":{
         "Type":"Pass",
         "End":true
      }
   }
}

Here is the new Amazon CloudFormation template for deploying the AWS Batch job definitions for each tool:

AWSTemplateFormatVersion: 2010-09-09

Description: Batch job definitions for batch genomics

Parameters:
  RoleStackName:
    Description: "Stack that deploys roles for genomic workflow"
    Type: String
  VPCStackName:
    Description: "Stack that deploys vps for genomic workflow"
    Type: String
  JobResultsBucket:
    Description: "Bucket that holds workflow job results"
    Type: String

Resources:
  IsaacJobDefinition:
    Type: AWS::Batch::JobDefinition
    Properties:
      JobDefinitionName: "Isaac"
      Type: container
      RetryStrategy:
        Attempts: 1
      Parameters:
        BAMS3FolderPath: !Sub "s3://${JobResultsBucket}/NA12878_states_1/bam"
        FastQ1S3Path: "s3://aws-batch-genomics-resources/fastq/SRR1919605_1.fastq.gz"
        FastQ2S3Path: "s3://aws-batch-genomics-resources/fastq/SRR1919605_2.fastq.gz"
        ReferenceS3Path: "s3://aws-batch-genomics-resources/reference/isaac/"
        WorkingDir: "/scratch"
      ContainerProperties:
        Image: "rulaszek/isaac"
        Vcpus: 32
        Memory: 80000
        JobRoleArn:
          Fn::ImportValue: !Sub "${RoleStackName}:ECSTaskRole"
        Command:
          - "--bam_s3_folder_path"
          - "Ref::BAMS3FolderPath"
          - "--fastq1_s3_path"
          - "Ref::FastQ1S3Path"
          - "--fastq2_s3_path"
          - "Ref::FastQ2S3Path"
          - "--reference_s3_path"
          - "Ref::ReferenceS3Path"
          - "--working_dir"
          - "Ref::WorkingDir"
        MountPoints:
          - ContainerPath: "/scratch"
            ReadOnly: false
            SourceVolume: docker_scratch
        Volumes:
          - Name: docker_scratch
            Host:
              SourcePath: "/docker_scratch"

  StrelkaJobDefinition:
    Type: AWS::Batch::JobDefinition
    Properties:
      JobDefinitionName: "Strelka"
      Type: container
      RetryStrategy:
        Attempts: 1
      Parameters:
        BAMS3Path: !Sub "s3://${JobResultsBucket}/NA12878_states_1/bam/sorted.bam"
        BAIS3Path: !Sub "s3://${JobResultsBucket}/NA12878_states_1/bam/sorted.bam.bai"
        ReferenceS3Path: "s3://aws-batch-genomics-resources/reference/hg38.fa"
        ReferenceIndexS3Path: "s3://aws-batch-genomics-resources/reference/hg38.fa.fai"
        VCFS3Path: !Sub "s3://${JobResultsBucket}/NA12878_states_1/vcf"
        WorkingDir: "/scratch"
      ContainerProperties:
        Image: "rulaszek/strelka"
        Vcpus: 32
        Memory: 32000
        JobRoleArn:
          Fn::ImportValue: !Sub "${RoleStackName}:ECSTaskRole"
        Command:
          - "--bam_s3_path"
          - "Ref::BAMS3Path"
          - "--bai_s3_path"
          - "Ref::BAIS3Path"
          - "--reference_s3_path"
          - "Ref::ReferenceS3Path"
          - "--reference_index_s3_path"
          - "Ref::ReferenceIndexS3Path"
          - "--vcf_s3_path"
          - "Ref::VCFS3Path"
          - "--working_dir"
          - "Ref::WorkingDir"
        MountPoints:
          - ContainerPath: "/scratch"
            ReadOnly: false
            SourceVolume: docker_scratch
        Volumes:
          - Name: docker_scratch
            Host:
              SourcePath: "/docker_scratch"

  SnpEffJobDefinition:
    Type: AWS::Batch::JobDefinition
    Properties:
      JobDefinitionName: "SNPEff"
      Type: container
      RetryStrategy:
        Attempts: 1
      Parameters:
        VCFS3Path: !Sub "s3://${JobResultsBucket}/NA12878_states_1/vcf/variants/genome.vcf.gz"
        AnnotatedVCFS3Path: !Sub "s3://${JobResultsBucket}/NA12878_states_1/vcf/genome.anno.vcf"
        CommandArgs: " -t hg38 "
        WorkingDir: "/scratch"
      ContainerProperties:
        Image: "rulaszek/snpeff"
        Vcpus: 4
        Memory: 10000
        JobRoleArn:
          Fn::ImportValue: !Sub "${RoleStackName}:ECSTaskRole"
        Command:
          - "--annotated_vcf_s3_path"
          - "Ref::AnnotatedVCFS3Path"
          - "--vcf_s3_path"
          - "Ref::VCFS3Path"
          - "--cmd_args"
          - "Ref::CommandArgs"
          - "--working_dir"
          - "Ref::WorkingDir"
        MountPoints:
          - ContainerPath: "/scratch"
            ReadOnly: false
            SourceVolume: docker_scratch
        Volumes:
          - Name: docker_scratch
            Host:
              SourcePath: "/docker_scratch"

  SamtoolsStatsJobDefinition:
    Type: AWS::Batch::JobDefinition
    Properties:
      JobDefinitionName: "SamtoolsStats"
      Type: container
      RetryStrategy:
        Attempts: 1
      Parameters:
        ReferenceS3Path: "s3://aws-batch-genomics-resources/reference/hg38.fa"
        BAMS3Path: !Sub "s3://${JobResultsBucket}/NA12878_states_1/bam/sorted.bam"
        BAMStatsS3Path: !Sub "s3://${JobResultsBucket}/NA12878_states_1/bam/sorted.bam.stats"
        WorkingDir: "/scratch"
      ContainerProperties:
        Image: "rulaszek/samtools-stats"
        Vcpus: 4
        Memory: 10000
        JobRoleArn:
          Fn::ImportValue: !Sub "${RoleStackName}:ECSTaskRole"
        Command:
          - "--bam_s3_path"
          - "Ref::BAMS3Path"
          - "--bam_stats_s3_path"
          - "Ref::BAMStatsS3Path"
          - "--reference_s3_path"
          - "Ref::ReferenceS3Path"
          - "--working_dir"
          - "Ref::WorkingDir"
        MountPoints:
          - ContainerPath: "/scratch"
            ReadOnly: false
            SourceVolume: docker_scratch
        Volumes:
          - Name: docker_scratch
            Host:
              SourcePath: "/docker_scratch"

Here is the new CloudFormation script that deploys the new workflow:

AWSTemplateFormatVersion: 2010-09-09

Description: State Machine for batch benomics

Parameters:
  RoleStackName:
    Description: "Stack that deploys roles for genomic workflow"
    Type: String
  VPCStackName:
    Description: "Stack that deploys vps for genomic workflow"
    Type: String

Resources:
  # S3
  GenomicWorkflow:
    Type: AWS::StepFunctions::StateMachine
    Properties:
      RoleArn:
        Fn::ImportValue: !Sub "${RoleStackName}:StatesExecutionRole"
      DefinitionString: !Sub |-
        {
           "Comment":"A simple example that submits a job to AWS Batch",
           "StartAt":"RunIsaacJob",
           "States":{
              "RunIsaacJob":{
                 "Type":"Task",
                 "Resource":"arn:aws:states:::batch:submitJob.sync",
                 "Parameters":{
                    "JobDefinition":"Isaac",
                    "JobName.$":"$.isaac.JobName",
                    "JobQueue":"HighPriority",
                    "Parameters.$": "$.isaac"
                 },
                 "TimeoutSeconds": 900,
                 "HeartbeatSeconds": 60,
                 "Next":"Parallel",
                 "InputPath":"$",
                 "ResultPath":"$.status",
                 "Retry" : [
                    {
                      "ErrorEquals": [ "States.Timeout" ],
                      "IntervalSeconds": 3,
                      "MaxAttempts": 2,
                      "BackoffRate": 1.5
                    }
                 ]
              },
              "Parallel":{
                 "Type":"Parallel",
                 "Next":"FinalState",
                 "Branches":[
                    {
                       "StartAt":"RunStrelkaJob",
                       "States":{
                          "RunStrelkaJob":{
                             "Type":"Task",
                             "Resource":"arn:aws:states:::batch:submitJob.sync",
                             "Parameters":{
                                "JobDefinition":"Strelka",
                                "JobName.$":"$.strelka.JobName",
                                "JobQueue":"HighPriority",
                                "Parameters.$": "$.strelka"
                             },
                             "TimeoutSeconds": 900,
                             "HeartbeatSeconds": 60,
                             "Next":"RunSnpEffJob",
                             "InputPath":"$",
                             "ResultPath":"$.status",
                             "Retry" : [
                                {
                                  "ErrorEquals": [ "States.Timeout" ],
                                  "IntervalSeconds": 3,
                                  "MaxAttempts": 2,
                                  "BackoffRate": 1.5
                                }
                             ]
                          },
                          "RunSnpEffJob":{
                             "Type":"Task",
                             "Resource":"arn:aws:states:::batch:submitJob.sync",
                             "Parameters":{
                                "JobDefinition":"SNPEff",
                                "JobName.$":"$.snpeff.JobName",
                                "JobQueue":"HighPriority",
                                "Parameters.$": "$.snpeff"
                             },
                             "TimeoutSeconds": 900,
                             "HeartbeatSeconds": 60,
                             "Retry" : [
                                {
                                  "ErrorEquals": [ "States.Timeout" ],
                                  "IntervalSeconds": 3,
                                  "MaxAttempts": 2,
                                  "BackoffRate": 1.5
                                }
                             ],
                             "End":true
                          }
                       }
                    },
                    {
                       "StartAt":"RunSamtoolsStatsJob",
                       "States":{
                          "RunSamtoolsStatsJob":{
                             "Type":"Task",
                             "Resource":"arn:aws:states:::batch:submitJob.sync",
                             "Parameters":{
                                "JobDefinition":"SamtoolsStats",
                                "JobName.$":"$.samtools.JobName",
                                "JobQueue":"HighPriority",
                                "Parameters.$": "$.samtools"
                             },
                             "TimeoutSeconds": 900,
                             "HeartbeatSeconds": 60,
                             "End":true,
                             "Retry" : [
                                {
                                  "ErrorEquals": [ "States.Timeout" ],
                                  "IntervalSeconds": 3,
                                  "MaxAttempts": 2,
                                  "BackoffRate": 1.5
                                }
                             ]
                          }
                       }
                    }
                 ]
              },
              "FinalState":{
                 "Type":"Pass",
                 "End":true
              }
           }
        }

Outputs:
  GenomicsWorkflowArn:
    Description: GenomicWorkflow ARN
    Value: !Ref GenomicWorkflow
  StackName:
    Description: StackName
    Value: !Sub ${AWS::StackName}

Conclusion

AWS Step Functions service integrations are a great way to simplify creating complex workflows with asynchronous steps. While we highlighted the use case with AWS Batch today, there are many other ways that healthcare and life sciences customers can use this new feature, such as with message processing.

For more information about how AWS can enable your genomics workloads, be sure to check out the AWS Genomics page.

We’ve updated the open-source project to take advantage of the new AWS Batch integration in Step Functions.  You can find the changes aws-batch-genomics/tree/v2.0.0 folder.

Original posts in this four-part series:

Happy coding!