fix(auth): route "Using keyring backend" log through tracing

[accounts-hash]

Problem

credential_store.rs::get_or_create_key writes the keyring-backend selection
line via raw eprintln!, bypassing the tracing infrastructure the crate
already builds:

// crates/google-workspace-cli/src/credential_store.rs:360 (main)
// Item 5: log which backend was selected
eprintln!("Using keyring backend: {}", backend.as_str());

Two visible consequences:

1. The documented GOOGLE_WORKSPACE_CLI_LOG env var cannot suppress it.
   gws --help advertises GOOGLE_WORKSPACE_CLI_LOG Log level for stderr (e.g., gws=debug),
   but gws=off, gws=warn, and gws=error all leave the banner on stderr.
2. Pipelines that merge stdout + stderr break. Any consumer that captures
   both streams (tee 2>&1, CI log captures, AI-agent tool harnesses that store
   merged output to a file) ends up with a non-JSON line prepended to otherwise
   pure-JSON stdout, breaking downstream parsers like | jq and
   python3 -c 'json.load(sys.stdin)'. This was the immediate trigger for the
   PR — an agent harness merged streams into a tool-result file, and the next
   step's cat … | jq choked on the leading banner.

Reproducer

$ GOOGLE_WORKSPACE_CLI_LOG=gws=off gws calendar events list \
    --params '{"calendarId":"primary","maxResults":1}' 2>&1 1>/dev/null
Using keyring backend: file        # expected: nothing on stderr

$ gws calendar events list --params '{"calendarId":"primary","maxResults":1}' 2>&1 \
    | python3 -c 'import sys,json; json.load(sys.stdin)'
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Fix

Replace the eprintln! with tracing::info! using the structured-fields style
already used in executor.rs:468-477 (tracing::warn! / tracing::debug! with
field = value, "Message"):

-    // Item 5: log which backend was selected
-    eprintln!("Using keyring backend: {}", backend.as_str());
+    // Item 5: log which backend was selected (audit trail; controlled by GOOGLE_WORKSPACE_CLI_LOG)
+    tracing::info!(backend = backend.as_str(), "Using keyring backend");

Why this is the right shape

• Preserves maintainer intent. The comment ("Item 5: log which backend was
  selected") indicates the line is intentional audit telemetry. Routing it
  through tracing keeps it audit-grade and adds it to the JSON log file
  pipeline that GOOGLE_WORKSPACE_CLI_LOG_FILE already builds.
• Backwards compatible. Default tracing subscriber level is INFO, so the
  message remains visible by default. Only users who actively opt out
  (GOOGLE_WORKSPACE_CLI_LOG=gws=warn) see a behavior change — and that change
  is exactly what gws --help already promises.
• Matches existing crate style. No new imports (the file is consistent with
  fully-qualified tracing::* calls used elsewhere). Structured backend = ...
  field is queryable in JSON logs, mirroring executor.rs.
• Minimal diff. 2 lines changed, no API changes, no test changes needed.

Verification

• tracing = "0.1" is already a workspace dep
  (crates/google-workspace-cli/Cargo.toml:64).
• The macro call shape is identical to existing usages in
  executor.rs:468-477. CI (.github/workflows/ci.yml) will compile-check the
  Rust paths filter on this PR.
• No new imports required; tracing is invoked fully-qualified, matching the
  file's existing convention.

Happy to amend with additional tests or a release-notes entry if useful.

Made with Cursor

[changeset-bot]

🦋 Changeset detected

Latest commit: eec74d6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@googleworkspace/cli	Patch

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[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request improves the logging behavior of the credential store by migrating a hardcoded stderr message to the application's structured tracing system. This change ensures that audit telemetry is properly configurable via environment variables and prevents unexpected output from breaking automated pipelines that rely on clean stream processing.

Highlights

• Logging Infrastructure: Replaced raw eprintln! with tracing::info! to integrate keyring backend selection into the existing tracing ecosystem.
• Log Suppression: Enables the use of GOOGLE_WORKSPACE_CLI_LOG to suppress the keyring backend banner, resolving issues where it could not be hidden.
• Pipeline Compatibility: Prevents the keyring banner from polluting stdout/stderr streams, ensuring downstream JSON parsers like jq function correctly.

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[gemini-code-assist]

Code Review

This pull request replaces a standard error print statement with structured logging using tracing::info! in the get_or_create_key function. This change allows for better log management and audit trailing, controlled by the GOOGLE_WORKSPACE_CLI_LOG environment variable. I have no feedback to provide.

[googleworkspace-bot]

/gemini review

[gemini-code-assist]

Code Review

This pull request migrates the "Using keyring backend" log message from a raw eprintln! to tracing::info!. This change allows the log output to be managed via the GOOGLE_WORKSPACE_CLI_LOG environment variable and ensures it is captured by the configured JSON log pipeline. I have no feedback to provide.