doc-module-06.md

module-06 : Create StepFunction and use a Stepfucntion in your application (20 mins)

• Create a Stepfunction
• Integrate Lambda Functions with a StepFunction

Reference

Create a Step function [Call a StepFunction] (https://aws.amazon.com/blogs/developer/stepfunctions-fluent-api/)

If you start from module-06 (from completed source code)

1. Run application

mvn compile package -Dmaven.test.skip=true

java -jar target/module-06-0.1.0.jar

2. Run unit Test and Curl

2.1 Run StepFunctionTest.java in hello.aws.stepfunction in src/testjava

2.2 Curl

• bucket=your bucket name
• prefix= your file prefix (for exmple, images/a.jpg)

curl 'localhost:8080/workshop/trans/integrated?bucket=<your_bucket>&prefix=<prefix>&region=<region>'

• You definitely got error above 2.1 and 2.2, it is because you don't have Lambda functions
• You need to create this following step 2

3. Create a StepFunction using JSON

3. 1. Change a step-function.json in main/resources/aws

• Change a resource value

{
  "Comment" : "Machine learning execution with spot instance",
  "StartAt" : "RetrieveInfoFromPhotoUsingRekognition",
  "States"  : {
    "RetrieveInfoFromPhotoUsingRekognition": {
      "Type"      : "Task",
      "Resource"  : "arn:aws:lambda:us-east-1:550622896891:function:MyFunction-workshop-rekognition",
      "Retry" : [ {"ErrorEquals":["HandledError"], "MaxAttempts":3} ],
      "Next"      : "TransInfoUsingTranlate"
    }, 
    "TransInfoUsingTranlate": {
      "Type"      : "Task",
      "Resource"  : "arn:aws:lambda:us-east-1:550622896891:function:MyFunction-workshop-translate",
      "Next"      : "StoreTransDataIntoDynamoDB"
    },
    "StoreTransDataIntoDynamoDB": {
      "Type"      : "Task",
      "Resource"  : "arn:aws:lambda:us-east-1:550622896891:function:MyFunction-workshop-dynamodb",    
      "Retry" : [ {"ErrorEquals":["HandledError"], "MaxAttempts":3} ],
      "End": true
  		}
  	}
}

3.2. Change a input file in same folder (step-input.json)

• change a bucket, prefix, sourceLangCode, targetLangCode

{
  "bucket":"seon-virginia-2016", 
  "prefix":"images/a.jpeg",
  "text" : "Hello, hello",
  "translated" : "",
  "sourceLangCode" :"en",
  "targetLangCode" : "es"
}

3.3 Create a StepFunction in your console

---

---

---

If you start from previous module (not completed source code)

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1. Create a StepFunction

1.1 Change event class of Lambda for StepFunction

Create a common Model class (StepEventInput, StepEventOutout)

StepEventInput.java (omit getter/setter)

	private String id;
	private String bucket;
	private String prefix;
	private String text;
	private String translated;
	private String sourceLangCode;
	private String targetLangCode;

StepEventOutput.java (omit getter/setter)

	private String text;
	private String error_message;

1.2 Create a StepFunction using JSON

1. Create a step-function.json in main/resources/aws

{
  "Comment" : "Machine learning execution with spot instance",
  "StartAt" : "RetrieveInfoFromPhotoUsingRekognition",
  "States"  : {
    "RetrieveInfoFromPhotoUsingRekognition": {
      "Type"      : "Task",
      "Resource"  : "arn:aws:lambda:us-east-1:550622896891:function:MyFunction-workshop-rekognition",
      "Retry" : [ {"ErrorEquals":["HandledError"], "MaxAttempts":3} ],
      "Next"      : "TransInfoUsingTranlate"
    }, 
    "TransInfoUsingTranlate": {
      "Type"      : "Task",
      "Resource"  : "arn:aws:lambda:us-east-1:550622896891:function:MyFunction-workshop-translate",
      "Next"      : "StoreTransDataIntoDynamoDB"
    },
    "StoreTransDataIntoDynamoDB": {
      "Type"      : "Task",
      "Resource"  : "arn:aws:lambda:us-east-1:550622896891:function:MyFunction-workshop-dynamodb",    
      "Retry" : [ {"ErrorEquals":["HandledError"], "MaxAttempts":3} ],
      "End": true
  		}
  	}
}

2. Create a input file in same folder (step-input.json)

{
  "bucket":"seon-virginia-2016", 
  "prefix":"images/a.jpeg",
  "text" : "Hello, hello",
  "translated" : "",
  "sourceLangCode" :"en",
  "targetLangCode" : "es"
}

1.3 Implement a test code

1. Create StepFunctionTest in hello.aws.stepfunction

final AWSStepFunctions stepFunctionclient = AWSStepFunctionsClientBuilder.defaultClient();

URL inputFile = Application.class.getResource("/aws/step-input.json");
String input = jsonFileRead(inputFile);
StartExecutionRequest startExecutionRequest 
= new StartExecutionRequest()
.withInput(input)
.withStateMachineArn("arn:aws:states:us-east-1:5591:stateMachine:workshop-stepfunction").withSdkRequestTimeout(30000);

StartExecutionResult executionResult = stepFunctionclient.startExecution(startExecutionRequest);

Test a code and check the result.