Understanding state and application workflows with AWS Step Functions

In this session, explore some of the latest features of AWS Step Functions and dive deep into how you can build complex workflows with them. From the new capabilities of the Amazon States Language to advanced integration patterns, this session covers the bits you might have missed that can enable you to do more with less code. Join this session to examine the types of solutions that can be built using Step Functions, such as approve/deny, error handling, and data science workflows.

Transcript

2. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. Understanding state and application workflows with AWS Step Functions Rob Sutter Sr. Developer Advocate AWS S V S 4 0 6
3. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. • Amazon States Language improvements • The lifecycle of a single step • Handling errors • Parallelism and concurrency • Additional resources Agenda
4. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. Amazon States Language improvements
5. • Updates to Choice state • Global access to the context object • Dynamic timeouts • Result selector • String construction • JSON <-> string conversion • Array construction Amazon States Language improvements s12d.com/asl-improvements
6. • IsNull – null • IsString – string • IsNumeric – numeric • IsBoolean – Boolean • IsTimestamp – timestamp Choice state – Comparison operators s12d.com/asl-improvements
7. IsPresent Choice state – Existence test s12d.com/asl-improvements
8. StringMatches Choice state – Wildcarding s12d.com/asl-improvements
9. StringEqualsPath Choice state – Variable to variable comparison s12d.com/asl-improvements
10. Global access to the context object s12d.com/asl-improvements
11. Turning this . . .
12. . . . into this
13. • TimeoutSecondsPath • HeartbeatSecondsPath Dynamic timeouts s12d.com/asl-improvements
14. Result selector s12d.com/asl-improvements
15. Turning this . . .
16. Turning this . . .
17. . . . into this
18. String construction s12d.com/asl-improvements
19. JSON <-> string conversion • JsonToString • StringToJson s12d.com/asl-improvements
20. Array construction s12d.com/asl-improvements
21. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. Step lifecycle
22. It all starts with an event . . .
23. . . . and some context
24. • InputPath • Task state • ResultSelector • ResultPath • OutputPath Order of operations Context ($$) State ($) Task InputPath ResultSelector OutputPath ResultPath $
25. “InputPath”: “$.InvokingEvent” Task InputPath ResultSelector OutputPath ResultPath
26. Task state Task InputPath ResultSelector OutputPath ResultPath
27. ResultSelector Task InputPath ResultSelector OutputPath ResultPath
28. “ResultPath”: “$.Detail.LockInfo” Task InputPath ResultSelector OutputPath ResultPath
29. “OutputPath”: “$.Detail” Task InputPath ResultSelector OutputPath ResultPath
30. Now state is transformed State ($) Task InputPath ResultSelector OutputPath ResultPath
31. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. Handling errors
32. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. “Complex systems run in degraded mode.” Richard I. Cook, MD MIT
33. • Task, Parallel, and Map states • Switch / case statement on ErrorEquals value • IntervalSeconds is the number of seconds before first retry • MaxAttempts is the number of retries (may be 0) • BackoffRate is a multiplier Retriers
34. • Task, Parallel, and Map states • Also known as fallback states • Scanned in array order when there is an error and no Retrier or all retries have failed • Switch / case statement on ErrorEquals value • ResultPath for storing error • Next defines the next state Catchers
35. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. Parallelism and concurrency
36. • Parallel invocations • Dynamic parallelism (Map state) • Function-native concurrency Parallelism and concurrency s12d.com/sfn-pc
37. • Total items in ItemsPath limited by state limit of 256 KB • MaxConcurrency theoretically limitless if set to 0 (default) • Practically, host affinity limits concurrent invocations to 40 • MaxConcurrency synchronous and sequential when set to 1 Dynamic parallelism (Map state) s12d.com/sfn-pc
38. © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. • Amazon States Language improvements • The lifecycle of a single step • Handling errors • Parallelism and concurrency • Additional resources at s12d.com/svs406 Review
39. Thank you! © 2020, Amazon Web Services, Inc. or its affiliates. All rights reserved. Rob Sutter Sr. Developer Advocate AWS Twitch: /robsutter Twitter: @rts_rob