AWS Step Functions

Overview

• Orchestration layer
• AWS manages the state between invocation
• Suitable for Serverless Lambda functions
• Simplified version of Simple Workflow Service
  • Uses SWF behind the scene
• Uses Amazon States Language (JSON) to express state

State

• Element of state machine (workflow)
  • Task (do some work)
  • Choice
  • Stop (Fail, Succeed)
  • Pass input->output 
  • Wait (delay timer)
  • Parallel 

Task

• Lambda function
• Activity
  • Performed by worker (EC2, ECS, mobile device)
  • Uses long polling

Error handling

• Retry
  • Task and Parallel states
  • ErrorEquals (what exception to handle)
  • Interval (delay after first attempt)
  • MaxAttempts
  • BackoffRate (how quickly interval increases)
• Catch
  • Fallback state

References

• https://www.youtube.com/watch?v=75MRve4nv8s