A follow-up to Counting OpenAI Tokens per Request in FastAPI .

I sent a document to evorag while the database was down.

OpenAI was called. The embedding was created. I paid for it.

Then the database write failed. The user got a 500.

My logs showed embedding.created . They did not show request.completed .

No status. No latency. No token count. The failed request was invisible.

That's the request I most needed to see.

Where it came from

In the last post, I built a logging middleware. This was its core:

metrics = start_metrics () started = time . perf_counter () response = await call_next ( request ) latency_ms = round (( time . perf_counter () - started ) * 1000 , 2 )

logger . info ( " request.completed " , ...)

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I tested the happy path. I never tested a route that raises.

If the route raises, call_next raises. Every line below it is skipped. The log never runs.

So my request log had a blind spot. Successful requests were logged. Failed ones disappeared.…