The Agent Crash-Looped on a Truncated Line: A Ledger Debugging Retrospective
The workflow had been running for six hours when the first alert fired. The apply stage was exiting with a JSONDecodeError, the supervisor was restarting it, and every restart died on the same line of the same file. The queue showed zero unacked messages, which meant the work was already marked done. I had a crash loop that would not die, and a set of decisions that were recorded but never…
The issue began when the apply stage of a workflow exited with a JSONDecodeError due to a truncated line in the ledger file. This caused the supervisor to restart the stage repeatedly, creating a crash loop. The problem was not related to the model's output, but rather how the pipeline handled the truncated data. To reproduce and fix the problem, the author set up a disposable server and a free token allowance to create a reproducible experiment.
The root cause was identified as an unhandled boundary condition in the pipeline, where the model output was appended raw and not validated before being written to the ledger. The author suggested three fixes: enveloping every record before writing, making the read path fail soft by skipping bad lines and moving them to quarantine, and alerting on quarantine to keep track of skipped records. These fixes prevented the crash loop and ensured the pipeline's reliability.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
