Configure Histogram Buckets for Latency SLOs
Set histogram bucket boundaries around the SLO threshold so p99 is accurate and not rounded into the wrong bucket.
Task
Instrument new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) so on-call engineers can diagnose an incident without guessing at log lines.
When to use this
An outage lasts 47 minutes because the team cannot correlate new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) across services without structured traces.
Prerequisites
- An application with structured logging available
- A metrics or tracing backend configured
Steps
1. Configure new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) in the project configuration file with the recommended defaults.
new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] })
Expected output: The configuration is accepted and new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) runs without errors on the first invocation.
2. Run the check locally to verify new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) produces the expected result before pushing.
pnpm test
Expected output: Local run matches CI behavior; no surprises after push.
3. Add the gate to the CI pipeline so new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) blocks merge on failure.
- name: Run add metrics histogram buckets
run: pnpm test
Expected output: Pull requests with failing new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) are blocked from merging.
Troubleshooting
Problem
The check passes locally but fails in CI
Solution
Pin dependency versions and the runtime to match CI exactly; reproduce with the same Docker image or act.
Problem
Configuration is rejected with a schema error
Solution
Check the tool version matches the config schema; older versions may not support newer fields.
Limitations
- The gate only runs on events that trigger the workflow; locally pushed commits bypass it.
- Configuration drift is possible if someone edits settings outside version control.
Make the system observable
Start by measuring the problem. Set histogram bucket boundaries around the SLO threshold so p99 is accurate and not rounded into the wrong bucket. The most common mistake is adding the gate without first confirming it catches the issue you care about. Run new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) against the current codebase and inspect the output before wiring it into CI.
new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] })Correlate across services
Once the gate is in place, make failures actionable. A failing new Histogram({ buckets: [0.005, 0.01, 0.05, 0.1, 0.5, 1, 5] }) should point to the exact file and line, not a generic error. Pin the tool version in the lockfile so a upstream release does not silently change behavior. Review the gate output in every pull request just like a test result.