Standard vs Express Workflows in AWS Step Functions

Overview

AWS Step Functions is a serverless orchestration service that lets you coordinate multiple AWS services into serverless workflows. It has two types of workflows: Standard and Express. Understanding the differences between these workflows can help you choose the right one for your application needs.

Key Concepts

• **Workflow Definition**: A series of steps that define how tasks are executed.
• **States**: Each step in a workflow.
• **Task**: A single unit of work, often implemented as an AWS Lambda function.
• **Transition**: The movement from one state to another.

Standard Workflows

Standard Workflows are designed for long-running, durable executions. They can run for up to one year and can handle higher concurrency.

Key Features

• Durable and stateful: Retain state over long periods.
• Execution History: Automatically stores the history of events.
• Long-running: Supports executions that can last for up to a year.

Use Cases

• Data processing pipelines.
• Long-running workflows, such as approval processes.
• Business processes that require human interaction.

Example Code Snippet

{
  "Comment": "A simple AWS Step Functions state machine that executes a lambda function",
  "StartAt": "MyLambdaFunction",
  "States": {
    "MyLambdaFunction": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:MyFunction",
      "End": true
    }
  }
}

Express Workflows

Express Workflows are designed for high-performance scenarios. They can execute in seconds and are optimized for throughput.

Key Features

• Short-lived: Ideal for workflows that complete in minutes or seconds.
• High throughput: Can handle thousands of executions per second.
• Cost-effective: Pay only for the requests you make.

Use Cases

• Real-time event processing.
• High-volume data ingestion pipelines.
• Microservices orchestration.

Example Code Snippet

{
  "Comment": "An Express Workflow that triggers a Lambda function",
  "StartAt": "ProcessEvent",
  "States": {
    "ProcessEvent": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:ProcessEvent",
      "End": true
    }
  }
}

Best Practices

• Choose the right workflow type based on your use case (Standard for long-running, Express for short-lived).
• Monitor executions and set up alarms for failures.
• Use error handling and retries to make workflows resilient.
• Keep workflows simple; complex workflows can be challenging to manage.

FAQ