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 ? .. 1 Overview of step Functions .. 1 Supported Regions .. 1 About Amazon Web Services.

2 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 .. 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.

3 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 .. 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.

4 27 step 4: Creating a State Machine with a Catch Field.. 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 .. 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.

5 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 .. 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.

6 69 Executions .. 70 Error Handling .. 71 Error Names .. 71 Retrying After an Error .. 71 Fallback States .. 73 Examples Using Retry and Using Catch .. 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 .. 100 Fallback States.

7 102 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 .. 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.

8 111 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.. 123 Creating IAM Roles for AWS step Functions .. 124 Create a Role for step Functions .. 124 Creating Granular IAM Permissions for Non-Admin Users .. 124 Service-Level Permissions .. 125 State Machine-Level Permissions .. 125 Execution-Level Permissions .. 126 Activity-Level Permissions .. 126 Related step Functions Resources .. 128 Document History .. 129 AWS Glossary.

9 136vAWS step Functions Developer GuideOverview of step FunctionsWhat Is AWS step Functions ?AWS step Functions is a web service that enables you to coordinate the components of distributedapplications and microservices using visual workflows. You build applications from individualcomponents that each perform a discrete function, or task, allowing you to scale and changeapplications quickly. step Functions provides a reliable way to coordinate components and stepthrough the Functions of your application. step Functions provides a graphical console to visualizethe components of your application as a series of steps. It automatically triggers and tracks each step ,and retries when there are errors, so your application executes in order and as expected, every Functions logs the state of each step , so when things do go wrong, you can diagnose and debugproblems Functions manages the operations and underlying infrastructure for you to ensure your applicationis available at any can run your tasks on the AWS Cloud, on your own servers, or on any system that has access to Functions can be accessed and used with the step Functions console, the AWS SDKs, or an HTTPAPI.

10 This guide shows you how to develop, test, and troubleshoot your own state machine using of step FunctionsHere are some of the key features of AWS step Functions : step Functions is based on the concepts of tasks (p. 53) and state machines (p. 52). You define state machines using the JSON-based Amazon States Language (p. 83). The step Functions console displays a graphical view of your state machine's structure, which providesyou with a way to visually check your state machine's logic and monitor RegionsCurrently, step Functions is supported only in the following regions: US East (Ohio) US East (N. Virginia) US West (Oregon) US West (N. California) Asia Pacific (Mumbai) Asia Pacific (Sydney) Asia Pacific (Tokyo) Asia Pacific (Seoul) EU (Frankfurt) EU (Ireland) EU (London) Canada (Central) Asia Pacific (Singapore)1 AWS step Functions Developer GuideAbout Amazon Web Services AWS GovCloud (US)About Amazon Web ServicesAmazon Web Services (AWS) is a collection of digital infrastructure services that developers can leveragewhen developing their applications.