Hold Slayer's logs are shipped to Loki by the host's Alloy agent, which
reads container stdout. Text lines arrive there as an opaque blob:
filtering on a status code meant regex over a formatted string. This adds
LOG_FORMAT=json (default "text", so local dev stays readable) rendering
one JSON object per line.
Two parts were less obvious than a format= argument would suggest, and
both are why this is a module rather than a basicConfig tweak:
Uvicorn attaches its own handlers to `uvicorn` and `uvicorn.access` with
propagate=False, so configuring only the root logger would have left the
access log — the highest-volume, most useful stream — as colourised text
next to our JSON. configure_logging clears those handlers and re-enables
propagation, and is called both at import (for startup config checks) and
in lifespan (uvicorn configures itself after importing the app). The
__main__ path passes log_config=None so uvicorn never applies its own.
The access record's payload lives in record.args as a 5-tuple, not in the
message. Formatting it would throw the structure away and force Loki to
parse it back out, so the tuple is unpacked into real fields and
status_code is emitted as a number for range filtering.
Also drops uvicorn's `color_message` extra, an ANSI-coloured duplicate of
the message that generic extra-promotion would otherwise copy into every
startup line — the same unreadable-in-Grafana problem recently fixed for
the lab's Asterisk logs.
Verified against a real uvicorn server: 39/39 lines valid JSON, zero ANSI
escapes, no duplicates, access lines structured with correct status codes;
text mode unchanged. Thread name is included off the main thread, since
"which execution context logged this" is the first question when debugging
across the asyncio/Sippy/PJSUA2 boundary. SecretStr extras stay masked.
README Phase 4 item ticked; LOG_FORMAT and the previously-undocumented
LOG_LEVEL added to the config table and .env.example.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Robert Helewka
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