How Do You Handle Idempotency in Multi-Step Automation?

At the API level, using idempotency keys generated by the caller is key. Then, have the receiver enforce these keys and store them in your workflow's durable ledger. This way, if a retry is necessary, you can do it secure in the knowledge of maintaining idempotency.

You can't really prevent duplicate writes unless every system involved has some sort of idempotency key. I recommend using a saga pattern where each step logically triggers the next upon completion. If a step fails, you can have it be timed to fail after several retries. By the way, what's the tech stack for your automation process? Knowing this could help in providing better advice.

It sounds like your saga coordinator might need some work. If it can't determine the state after a cold start, you might want to rethink how you track actions within a saga. That unknown outcome scenario is tough — when a call times out, sometimes the downstream write might go through but you won't be sure. We try to keep intent recorded before any side effects and track outcomes after using unique identifiers. What setup do you use for coordination? Are you leveraging a framework like Temporal or a custom solution?

One approach we've taken for migrations is creating a DynamoDB table to log whether each step has been completed. If it has, we simply skip it on a retry. This won't cover all cases but it's one solution to consider when idempotency isn't built-in. For larger processes, implementing an SQS queue can also help in managing task flow. I feel like most operations could be designed to be idempotent, like checking for existing tickets before creating new ones.

I find it's most effective to enforce idempotency at each task, rather than at the orchestrator level. Each step should be able to check if the desired resource state is already met — for tasks like sending notifications, a simple state marker can help. If it finds the marker, it skips the operation, which prevents the orchestrator's retry logic from getting too complicated. The crucial thing is ensuring if a task is run twice, it just doesn't break the system.