Fix concurrent JSON read-modify-write race (2 gunicorn workers, no lock) #13

New Issue

tonym · 2026-06-06T19:58:12Z

tonym commented

2026-06-06 19:58:12 +00:00

Severity: high
Category: data-integrity
Location: app.py:198-200, Dockerfile:29

Problem

With --workers 2, two concurrent POSTs both load, modify, and write the same file — last write wins and silently discards the other.

Suggested fix

Drop to --workers 1 (fine for a single household) or use fcntl.flock/filelock around load+save.

Filed by automated code review.

**Severity:** high **Category:** data-integrity **Location:** `app.py:198-200, Dockerfile:29` ### Problem With `--workers 2`, two concurrent POSTs both load, modify, and write the same file — last write wins and silently discards the other. ### Suggested fix Drop to `--workers 1` (fine for a single household) or use `fcntl.flock`/`filelock` around load+save. _Filed by automated code review._

tonym added the

data-integrity

severity:high

labels 2026-06-06 19:58:12 +00:00

tonym referenced this issue from a commit

2026-06-06 21:34:10 +00:00

Harden JSON storage (atomic writes + crash-safe loads) + suggestions lightbulb

Sign in to join this conversation.