This package was created by Maxim Fateev (original author of the Flow Framework) from aws/aws-swf-flow-library official AWS package. It uses standard Maven directory structure and supports invocation of the examples using mvn exec as oposed official version that uses ant.

The package uses AWS Flow Framework from https://github.com/mfateev/swf-flow-library-java which is not found in global maven repositories yet.

AWS Flow Framework Samples

These samples demonstrate how to use AWS Flow Framework. The following samples are included:

• HelloWorld -- this sample includes a very simple workflow that calls an activity to print hello world to the console. It shows the basic usage of AWS Flow Framework, including defining contracts, implementation of activities and workflow coordination logic and worker programs to host them.

• HelloLambda -- this sample shows how you can create a workflow that calls an AWS Lambda task instead of a traditional Amazon SWF activity.

• Booking -- shows an example workflow for making a reservation, including flight and rental car.

• FileProcessing -- shows a workflow for media processing use case. The sample workflow downloads a file from an Amazon S3 bucket, creates a zip file and uploads that zip file back to S3. The sample uses the task routing feature.

• PeriodicWorkflow -- shows how to create a workflow that periodically executes an activity. The workflow can run for extended periods and hence it uses the continue as new execution feature.

• SplitMerge -- the workflow in this sample processes a large data set by splitting it up into smaller data sets. The sample calculates the average of a large set of numbers stored in a file in S3. The smaller data sets are assigned to workers and the results of processing are merged to produce the final result.

• Deployment -- the workflow in this sample shows deployment of interdependent components.

• Cron -- the workflow in this sample starts an activity periodically based on a cron schedule.

• CronWithRetry -- this is an enhanced version of the Cron sample that uses the exponential retry feature to retry the activity if it fails.

Prerequisites

• A valid Amazon Web Services developer account. To sign up, go to http://aws.amazon.com.

• The AWS SDK for Java. For more information about the AWS SDK for Java, see http://aws.amazon.com/sdkforjava.

• You must be signed up for the following services:

  • Amazon Simple Workflow Service (SWF). For more information, see http://aws.amazon.com/swf.

  • Amazon Simple Storage Service (S3). For more information, see http://aws.amazon.com/s3.

• JUnit (version 4.7). The jar file must be in the classpath. For more information, see http://www.junit.org/.

• org.springframework.test (version 3.0). The jar file must be in the classpath. For more information, see http://www.springsource.org/.

• Log4j (version 1.2.15). The jar file must be in the classpath. For more information, see http://logging.apache.org/log4j/1.2/.

Configuring and Building the samples

The steps for configuring and building the AWS Flow Framework for Java samples are:

1. Create the Samples domain. You can do this either with the AWS Management Console or using the AWS CLI.

   To create the Samples domain using the AWS Management Console

   a. Go to the SWF Management Console https://console.aws.amazon.com/swf/home. b. Follow the on-screen instructions to log in. c. Click Manage Domains and register a new domain with the name Samples.

   To create the Samples domain using the AWS CLI

   • Execute the following command:

       aws swf register-domain --name Samples --workflow-execution-retention-period-in-days 1
     

     Note: to use this option, you must have installed and set up the AWS CLI as described in the AWS CLI documentation.

2. Open the access.properties file in the samples directory.

3. Locate the following sections and fill in your Access Key ID and Secret Access Key. You can use the same values for SWF and S3:

    # Fill in your AWS Access Key ID and Secret Access Key for SWF
    # http://aws.amazon.com/security-credentials
    AWS.Access.ID=<Your AWS Access Key>
    AWS.Secret.Key=<Your AWS Secret Key>
    AWS.Account.ID=<Your AWS Account ID>
   
    # Fill in your AWS Access Key ID and Secret Access Key for S3
    # http://aws.amazon.com/security-credentials
    S3.Access.ID=<Your AWS Access Key>
    S3.Secret.Key=<Your AWS Secret Key>
    S3.Account.ID=<Your AWS Account ID>
   

4. Save the access.properties file.

5. Set the environment variable AWS_SWF_SAMPLES_CONFIG to the full path of the directory containing the access.properties file.

   On Linux, Unix or OS X, use this command to set the environment variable:

    export AWS_SWF_SAMPLES_CONFIG=<Your SDK Directory>/src/samples/AwsFlowFramework
   

   On Windows run this command:

    set AWS_SWF_SAMPLES_CONFIG=<Your SDK Directory>/src/samples/AwsFlowFramework
   

6. Compile the samples by using the Ant build.xml file. This will create binaries in the samples/bin directory.

Running the samples

Each sample has particular requirements for running it. Here's how to run each of the samples once you've built them using the preceding instructions.

Hello World

The sample has three executables. You should run each command in a separate terminal window, from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.helloworld.ActivityHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.helloworld.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.helloworld.WorkflowExecutionStarter

Hello Lambda

The HelloLambda sample requires the use of an AWS Lambda function. You can create the function in any way supported by AWS Lambda, including by using the AWS Eclipse Toolkit.

Note: Using Lambda can incur costs to your AWS account. For more information, see the AWS Lambda Pricing page.

Visit the following pages to learn how to create AWS Lambda functions:

• in Java using Eclipse.

• in Java without Eclipse.

• in Node.js.

When you create the function, be sure that it exists in the same AWS region that you will run the HelloLambda sample in. You will also need to provide Amazon SWF with access to your Lambda function in order to run it using the sample.

To create a Lambda role for SWF:

1. Open the Amazon IAM console

2. Click Roles, then Create New Role.

3. Give your role a name, such as `swf-lambda' and click Next Step.

4. Under AWS Service Roles, choose AWS SWF, and click Next Step.

5. Choose AWSLambdaRole from the list, click Next Step and then Create Role once you've reviewed the role.

   Once you have a Lambda function to run and an IAM policy that gives SWF access to it, then find the following section in the access.properties file and provide it with information about the function and role that you created:

    ####### HelloLambda Sample Config Values ######
    SWF.LambdaRole.ARN=<Your IAM role that authorizes SWF to invoke Lambda functions>
    SWFLambdaFunction.Name=<The name of your Lambda function>
    SWFLambdaFunction.Input=<Input for your Lambda function>
   

The HelloLambda sample uses an AWS Lambda task instead of running an activity, so you only need to run the workflow host and workflow starter. Run each command in a separate terminal window from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.hellolambda.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.hellolambda.WorkflowExecutionStarter

Booking

The sample has three executables. You should run each command in a separate terminal window, from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.booking.ActivityHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.booking.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.booking.WorkflowExecutionStarter

Cron

The sample has three executables. You should run each command in a separate terminal window, from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.cron.ActivityHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.cron.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.cron.CronWorkflowExecutionStarter -Dexec.args="\"*/10 * * * * *\" PST 60"

The workflow starter takes three command line arguments that must be specified:

1. CRON_PATTERN: specifies the pattern used to determine the cron schedule for the periodic activity task. The above command specifies the pattern */10 * * * * * to run the task every 10 seconds.

2. TIME_ZONE: specifies the time zone to use for time calculations. The above command specifies PST (Pacific Standard Time).

3. CONTINUE_AS_NEW_AFTER_SECONDS: specifies the duration, in seconds, after which the current execution should be closed and continued as a new execution. The above command specifies 60 seconds.

Cron With Retry

The sample has three executables. You should run each command in a separate terminal window, from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.cronwithretry.ActivityHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.cronwithretry.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.cronwithretry.CronWithRetryWorkflowExecutionStarter" -Dmain-args="\"*/10 * * * * *\" PST 60

The workflow starter takes three command line arguments that must be specified:

1. CRON_PATTERN: specifies the pattern used to determine the cron schedule for the periodic activity task. The above command specifies the pattern */10 * * * * * to run the task every 10 seconds.

2. TIME_ZONE: specifies the time zone to use for time calculations. The above command specifies PST (Pacific Standard Time).

3. CONTINUE_AS_NEW_AFTER_SECONDS: specifies the duration, in seconds, after which the current execution should be closed and continued as a new execution. The above command specifies 60 seconds.

File Processing

The FileProcessing sample uploads files to Amazon S3. To run this sample, you will need to first create an S3 bucket.

Then, locate the following section in the access.properties file and fill in the name of an S3 bucket that you want the sample to use:

    ####### FileProcessing Sample Config Values ##########
    Workflow.Input.TargetBucketName=<Your S3 bucket name>

The sample has three executables. You should run each command in a separate terminal window, from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.fileprocessing.ActivityHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.fileprocessing.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.fileprocessing.WorkflowExecutionStarter

Periodic Workflow

The sample has three executables. You should run each command in a separate terminal window, from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.periodicworkflow.ActivityHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.periodicworkflow.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.periodicworkflow.WorkflowExecutionStarter

Split Merge

The sample has three executables. You should run each command in a separate terminal window, from the samples directory.

mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.splitmerge.ActivityHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.splitmerge.WorkflowHost
mvn exec:java -Dexec.mainClass=com.amazonaws.services.simpleworkflow.flow.examples.splitmerge.WorkflowExecutionStarter