step-functions

# AWS Step Functions

AWS Step Functions is a serverless orchestration service that lets you build and run workflows using state machines. Coordinate multiple AWS services into business-critical applications.

## Table of Contents

- [Core Concepts](#core-concepts)
- [Common Patterns](#common-patterns)
- [CLI Reference](#cli-reference)
- [Best Practices](#best-practices)
- [Troubleshooting](#troubleshooting)
- [References](#references)

## Core Concepts

### Workflow Types

| Type | Description | Pricing |
|------|-------------|---------|
| **Standard** | Long-running, durable, exactly-once | Per state transition |
| **Express** | High-volume, short-duration | Per execution (time + memory) |

### State Types

| State | Description |
|-------|-------------|
| **Task** | Execute work (Lambda, API call) |
| **Choice** | Conditional branching |
| **Parallel** | Execute branches concurrently |
| **Map** | Iterate over array |
| **Wait** | Delay execution |
| **Pass** | Pass input to output |
| **Succeed** | End successfully |
| **Fail** | End with failure |

### Amazon States Language (ASL)

JSON-based language for defining state machines.

## Common Patterns

### Simple Lambda Workflow

```json
{
  "Comment": "Process order workflow",
  "StartAt": "ValidateOrder",
  "States": {
    "ValidateOrder": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:ValidateOrder",
      "Next": "ProcessPayment"
    },
    "ProcessPayment": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:ProcessPayment",
      "Next": "FulfillOrder"
    },
    "FulfillOrder": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:FulfillOrder",
      "End": true
    }
  }
}
```

### Create State Machine

**AWS CLI:**

```bash
aws stepfunctions create-state-machine \
  --name OrderWorkflow \
  --definition file://workflow.json \
  --role-arn arn:aws:iam::123456789012:role/StepFunctionsRole \