AWS Step Functions

1 AWS step FunctionsDeveloper GuideAWS step Functions Developer GuideAWS step Functions : Developer GuideCopyright 2018 Amazon Web Services, Inc. and/or its affiliates. All rights 's trademarks and trade dress may not be used in connection with any product or service that is not Amazon's, in any mannerthat is likely to cause confusion among customers, or in any manner that disparages or discredits Amazon. All other trademarks notowned by Amazon are the property of their respective owners, who may or may not be affiliated with, connected to, or sponsored step Functions Developer GuideTable of ContentsWhat Is AWS step Functions ?

2 1 Overview of step Functions .. 1 Supported Regions .. 1 About Amazon Web Services .. 2 Getting Started .. 3 step 1: creating a State Machine .. 3To create the state machine .. 3 step 2: Starting a New Execution .. 4To start a new execution .. 4 step 3: (Optional) Update a State Machine .. 5To update a state machine .. 5 Next Steps .. 6 Tutorials .. 7 Development Options .. 7 step Functions Console .. 7 AWS SDKs .. 7 HTTPS Service API .. 7 Development Environments.

3 8 Endpoints.. 8 AWS CLI .. 8 creating a Lambda State Machine .. 8 step 1: creating an IAM Role for Lambda .. 9 step 2: creating a Lambda Function .. 9 step 3: Testing the Lambda Function .. 10 step 4: creating a State Machine .. 10 step 5: Starting a New Execution .. 12 creating a Lambda State Machine Using AWS CloudFormation .. 13 step 1: Setting Up Your AWS CloudFormation Template .. 13 step 2: Using the AWS CloudFormation Template to Create a Lambda State Machine .. 16 step 3: Starting a State Machine Execution.

4 20 creating an Activity State Machine .. 20 step 1: creating a New Activity .. 21 step 2: creating a State Machine .. 21 step 3: Implementing a Worker .. 22 step 4: Starting an Execution .. 24 step 5: Running and Stopping the Worker .. 25 Handling Error Conditions Using a State Machine .. 25 step 1: creating an IAM Role for Lambda .. 26 step 2: creating a Lambda Function That Fails .. 26 step 3: Testing the Lambda Function .. 27 step 4: creating a State Machine with a Catch Field.

5 27 step 5: Starting a New Execution .. 29 Starting a State Machine Execution Using CloudWatch Events .. 30 step 1: creating a State Machine .. 30 step 2: creating a CloudWatch Events Rule .. 31 creating a step Functions API Using API Gateway .. 32 step 1: creating an IAM Role for API Gateway .. 33 step 2: creating your API Gateway API .. 33 step 3: Testing and Deploying the API Gateway API .. 35 Iterating a Loop Using Lambda.. 37 step 1: Create a Lambda Function to Iterate a Count.

6 37 step 2: Test the Lambda Function .. 38 step 3: Create a State Machine .. 39 step 4: Start a New Execution .. 42iiiAWS step Functions Developer GuideContinue as a New Execution .. 43 Prerequisites .. 45 step 1: Create an Iterate Lambda Function to Iterate a Count .. 45 step 2: Create a Restart Lambda Function to Start a New step Functions Execution .. 47 step 3: Create a State Machine .. 48 step 4: Update the IAM Policy .. 50 step 5: Run an Execution .. 50 How step Functions Works.

7 52 States.. 52 Tasks .. 53 Activities .. 53 creating an Activity .. 54 Writing a Worker .. 54 Example Activity Worker in Ruby .. 54 Transitions .. 60 State Machine Data.. 61 Data Format .. 61 State Machine Input/Output.. 62 State Input/Output.. 62 Input and Output Processing .. 63 Understanding ResultPath.. 64 Filtering with InputPath and OutputPath.. 69 Executions .. 70 Error Handling .. 71 Error Names .. 71 Retrying After an Error .. 71 Fallback States .. 73 Examples Using Retry and Using Catch.

8 74 Read Consistency .. 77 Templates .. 77 Sample Projects .. 78 Job Status Poller .. 78 Task Timer .. 81 Amazon States Language .. 83 Example Amazon States Language Specification .. 83 State Machine Structure .. 84 States.. 85 Common State Fields.. 86 Pass .. 86 Task .. 87 Choice .. 90 Wait .. 93 Succeed .. 94 Fail .. 94 Parallel .. 94 Input and Output Processing .. 97 Paths .. 97 Reference Paths .. 97 Errors .. 100 Error Representation .. 100 Retrying After an Error.

9 100 Fallback States .. 102 Best Practices .. 104 Use Timeouts to Avoid Stuck Executions .. 104 Use ARNs Instead of Passing Large Payloads .. 104 Avoid Reaching the History Limit .. 104 Handle Lambda Service Exceptions .. 105ivAWS step Functions Developer GuideLimits.. 106 General Limits.. 106 Limits Related to Accounts .. 106 Limits Related to State Machine Executions .. 107 Limits Related to Task Executions .. 107 Limits Related to API Action Throttling .. 108 Limits Related to State Throttling.

10 109 Requesting a Limit Increase .. 109 Monitoring and Logging.. 110 Monitoring step Functions Using CloudWatch .. 110 Metrics that Report a Time Interval .. 111 Metrics that Report a Count .. 111 State Machine Metrics.. 111 Viewing Metrics for step Functions .. 114 Setting Alarms for step Functions .. 115 Logging step Functions using AWS CloudTrail .. 117 step Functions Information in CloudTrail .. 117 Example: step Functions Log File Entries .. 118 Security .. 123 Authentication.