Faults versus errors

A FAULT is the target REFUSING. An ERROR is the flow BREAKING. The distinction decides where your handler goes. A fault comes back from something you called: the service returned an error, the target rejected the record, the adapter reported a problem with the request. It is a response, and it is CATCHABLE — you can wrap the invoke, catch the fault, read what it said, and decide. An error is your flow failing: a null in an expression, a variable read before assignment, a payload too large, a mapping that could not produce valid output. Some of these the platform catches and some end the instance where it stands. WHY THE DISTINCTION DECIDES WHERE THE HANDLER GOES. A fault handler wrapped around one invoke catches that target's refusals and knows exactly which call failed and why. A handler at the top of the flow catches everything and knows almost…

In this module: Module 8 · Error handling, faults and retries

1. 1The four kinds of failure
2. 2Faults versus errorsFree preview
3. 3Scope and fault handlers
4. 4What to do with a caught fault
5. 5Retry: how many, how far apart
6. 6The dead letter, and who reads it
7. 7Partial failure in a batch
8. 8Compensation, and its limits
9. 9Alerting a human
10. 10Resubmission: doing it safely
11. 11Errors that are not failures
12. 12What breaks: five error-handling failures
13. 13Lab briefing · Break it five ways