Cosmos: downgrade request-status error logs to debug by Copilot · Pull Request #4711 · Azure/azure-sdk-for-rust

Copilot · 2026-07-07T22:25:20Z

Create-if-not-exists and similar flows can intentionally treat non-2xx service responses (for example, 409 Conflict) as successful control flow. The Cosmos pipeline was emitting high-severity logs for these outcomes, creating noisy WARN/ERROR output under normal usage.

Pipeline abort logging severity
- Changed operation_pipeline abort-path logging from tracing::error! to tracing::debug! for terminal operation outcomes that include typed Cosmos HTTP status.
Hedged terminal HTTP outcome severity
- Changed hedged terminal HTTP status logging (cosmos.hedge.terminal_http_error) from tracing::warn! to tracing::debug!.
Behavioral impact
- Status/sub-status telemetry remains logged, but request-status messages no longer surface as warn/error by default for user-handled HTTP outcomes.

// before
tracing::error!(status = ?cosmos_status, "operation aborted");
tracing::warn!(http_status = u16::from(status.status_code()), "cosmos.hedge.terminal_http_error");

// after
tracing::debug!(status = ?cosmos_status, "operation aborted");
tracing::debug!(http_status = u16::from(status.status_code()), "cosmos.hedge.terminal_http_error");

Co-authored-by: analogrelay <7574+analogrelay@users.noreply.github.com>

azure-pipelines · 2026-07-24T18:48:54Z

Azure Pipelines: Successfully started running 1 pipeline(s). 2 pipeline(s) were filtered out due to trigger conditions. There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Pull request overview

Downgrades Cosmos HTTP-status logging to reduce noise from expected control-flow responses.

Changes:

Changes pipeline abort logs from error to debug.
Changes hedged terminal HTTP logs from warning to debug.

Show a summary per file

File	Description
`operation_pipeline.rs`	Lowers terminal outcome log severity.

Review details

Files reviewed: 1/1 changed files
Comments generated: 1
Review effort level: Medium

analogrelay

@copilot While you're fixing up the issues below, look out for any places where we're tracing "event name"-style strings like cosmos.hedge.terminal_http_error. Tracing events should have human-readable log-line-style messages.

analogrelay · 2026-07-24T18:55:16Z

@copilot This one should probably be debug! as well.

Done in 16ae25a. This log is now emitted at debug!.

analogrelay · 2026-07-24T18:55:55Z

@copilot Fix this up to use a human-readable log line instead of an "event name" style. Something like non-retriable http error in hedging attempt

Updated in 16ae25a. This now uses a human-readable message: non-retriable http error in hedging attempt.

analogrelay · 2026-07-24T18:56:01Z

@copilot Fix this up to use a human-readable log line instead of an "event name" style. Something like non-retriable transport error in hedging attempt

Updated in 16ae25a. This now uses a human-readable message: non-retriable transport error in hedging attempt.

Co-authored-by: analogrelay <7574+analogrelay@users.noreply.github.com>

Copilot · 2026-07-24T19:07:39Z

@copilot While you're fixing up the issues below, look out for any places where we're tracing "event name"-style strings like cosmos.hedge.terminal_http_error. Tracing events should have human-reada...

Addressed in 16ae25a. Updated the touched hedging terminal tracing events to use human-readable log-line messages instead of event-name-style strings.

No longer relevant

NaluTripician · 2026-07-28T19:45:50Z

Do we need a changelog entry here?

Additionally, I think this might introduce some conflict with the specs.

§10.4's level table and OTel-naming note are now partially contradicted.

NaluTripician · 2026-07-28T19:48:34Z

                request_count = diagnostics.request_count(),
                http_status = u16::from(status.status_code()),
                sub_status = ?status.sub_status(),
-                "cosmos.hedge.terminal_http_error",


No migration note for anyone alerting on cosmos.hedge.terminal_http_error — string is gone. Breaking for log-based alerting, or never a supported surface? (§10.4 says "reserved," which cuts toward the latter.)

analogrelay · 2026-07-28T21:00:09Z

@copilot Can you address @NaluTripician 's two comments? Specifically:

Do we need a changelog entry here?

No migration note for anyone alerting on cosmos.hedge.terminal_http_error — string is gone. Breaking for log-based alerting, or never a supported surface? (§10.4 says "reserved," which cuts toward the latter.)

Yes, but we don't need detail. It can simply say "Changes the messages and severity of some tracing events". It's early enough that I'm not worried about being hyper-accurate there. Add that CHANGELOG entry (ensure you reference this PR as all the others do)

Additionally, I think this might introduce some conflict with the specs.

Update relevant hedging specs for the change in event text.

Co-authored-by: analogrelay <7574+analogrelay@users.noreply.github.com>

Copilot · 2026-07-28T21:05:12Z

@copilot Can you address @NaluTripician 's two comments? Specifically:

Do we need a changelog entry here?
...

Addressed in 74c6479.

Added a Cosmos driver changelog entry under 0.38.0 (Unreleased) with the requested wording and PR reference.
Updated HEDGING_SPEC.md §10.4 to align with the current human-readable hedging terminal log text and clarify that those terminal messages/levels are outside the reserved telemetry-name contract.

Initial plan

e6cd6a5

Copilot AI assigned Copilot and analogrelay Jul 7, 2026

Copilot started work on behalf of analogrelay July 7, 2026 22:26 View session

Copilot AI linked an issue Jul 7, 2026 that may be closed by this pull request

Cosmos: Avoid tracing "WARN" or "ERROR" messages for user-triggered errors #4707

Open

Lower Cosmos HTTP error logs to debug

2f195c1

Co-authored-by: analogrelay <7574+analogrelay@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix logging of user-triggered errors in Cosmos DB~~ Cosmos: downgrade request-status error logs to debug Jul 7, 2026

Copilot finished work on behalf of analogrelay July 7, 2026 22:31

Copilot AI requested a review from analogrelay July 7, 2026 22:31

Merge branch 'main' into copilot/fix-cosmos-tracing-levels

dfb4a56

analogrelay marked this pull request as ready for review July 24, 2026 18:48

analogrelay requested a review from a team as a code owner July 24, 2026 18:48

Copilot AI review requested due to automatic review settings July 24, 2026 18:48

Copilot started reviewing on behalf of analogrelay July 24, 2026 18:49 View session

Copilot AI reviewed Jul 24, 2026

View reviewed changes

Comment thread sdk/cosmos/azure_data_cosmos_driver/src/driver/pipeline/operation_pipeline.rs

analogrelay previously requested changes Jul 24, 2026

View reviewed changes

Copilot started work on behalf of analogrelay July 24, 2026 18:58 View session

Refine hedge terminal tracing logs

16ae25a

Co-authored-by: analogrelay <7574+analogrelay@users.noreply.github.com>

Copilot AI requested review from Copilot and removed request for Copilot July 24, 2026 19:07

Copilot finished work on behalf of analogrelay July 24, 2026 19:08

Copilot AI requested a review from analogrelay July 24, 2026 19:08

NaluTripician reviewed Jul 28, 2026

View reviewed changes

Copilot started work on behalf of analogrelay July 28, 2026 21:01 View session

Update hedging spec and changelog

74c6479

Co-authored-by: analogrelay <7574+analogrelay@users.noreply.github.com>

Copilot AI review requested due to automatic review settings July 28, 2026 21:04

Copilot AI removed the request for review from Copilot July 28, 2026 21:04

Copilot finished work on behalf of analogrelay July 28, 2026 21:05

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Copilot AI commented Jul 7, 2026 •

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