chore: reduce Sentry span sampling outside development

[brendan-kellam]

Fixes SOU-1557

Summary

• retain 100% Sentry span sampling in development
• sample 10% of spans in the browser, Next.js server and edge runtimes, and backend worker in every other environment
• leave Sentry error event sampling unchanged

Testing

• yarn workspace @sourcebot/web exec eslint src/instrumentation-client.ts src/sentry.server.config.ts src/sentry.edge.config.ts
• yarn workspace @sourcebot/backend exec tsc --noEmit
• yarn workspace @sourcebot/web exec tsc --noEmit --skipLibCheck --target es2022 --module esnext --moduleResolution bundler src/instrumentation-client.ts src/sentry.edge.config.ts src/sentry.server.config.ts

Summary by CodeRabbit

• Chores
  • Adjusted Sentry performance/error capture sampling to use 100% in development and 10% outside development.
  • Applied consistently across backend, web client, server, and edge Sentry initialization.
• Documentation
  • Updated the changelog to reflect the environment-based sampling change.

[coderabbitai]

Walkthrough

Sentry initialization now uses a full tracing sample rate in development and a 10% rate elsewhere across backend, client, edge, and server runtimes. The changelog records this configuration change.

Changes

Sentry sampling configuration

Layer / File(s)	Summary
Apply environment-based sampling packages/backend/src/instrument.ts, packages/web/src/instrumentation-client.ts, packages/web/src/sentry.edge.config.ts, packages/web/src/sentry.server.config.ts, CHANGELOG.md	Sentry uses a 1.0 tracesSampleRate in development and 0.1 otherwise across all initialization paths, and the changelog documents the change.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• sourcebot-dev/sourcebot#1431: Modifies Sentry initialization options in two of the same web configuration files.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: lowering Sentry sampling to 10% outside development.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch brendan-kellam/sentry-event-sampling-SOU-1557

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[cursor]

Dev sampling gate never matches

Medium Severity

The Sentry sampleRate in development environments defaults to 0.1 instead of 1.0. This occurs because the backend's Sentry configuration compares NEXT_PUBLIC_SENTRY_ENVIRONMENT to 'development', while the .env.development file sets it to 'dev', preventing full error capture.

 

^{Reviewed by Cursor Bugbot for commit 5e991c4. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 2 potential issues.

There are 3 total unresolved issues (including 1 from previous review).

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit af8c811. Configure here.}

[cursor]

Wrong Sentry sampling option

High Severity

The change intended to sample Sentry error events at 10% outside development. Instead, tracesSampleRate was modified, leaving error capture at 100%. This samples web traces and associated profiling at 10% (instead of 100%) and newly enables backend performance tracing.

 

^{Reviewed by Cursor Bugbot for commit af8c811. Configure here.}

[cursor]

Dev sampling env mismatch

Medium Severity

The tracesSampleRate condition expects NEXT_PUBLIC_SENTRY_ENVIRONMENT to be 'development' for full sampling. The .env.development example uses 'dev', which means development environments will get a reduced sampling rate (0.1) instead of 1.0.

 

^{Reviewed by Cursor Bugbot for commit af8c811. Configure here.}