Build the safeguards
Eight explained steps, a source example and a checkpoint at each decision.
Read the tutorialOpenTelemetry / Observability / SLOs
The server is healthy. Customers are waiting.
Every request returns successfully. One takes much longer than the others. Follow its spans, find the missing context and choose a signal that reflects the customer’s wait.
The idea in plain language
A successful response can still be a poor experience. Metrics tell you how often that happens; a trace helps explain where a particular request spent its time.
The worker creates real OpenTelemetry spans around actual timer waits. The database is a timed fixture. Eight requests teach latency arithmetic, not a production SLO window. A local HTTP service and optional Prometheus/Grafana recipe accompany the download.
Your independent testing environment
Make the failure visible.
Run the slow-query example. Inspect the mean, p95 and under-100-ms fraction. In the safeguarded trace, the database span shares the customer request’s trace ID instead of starting an unrelated root.
Compare a green availability signal with the slow request’s trace and latency.
Ready. Choose an example and run both implementations.
Explain the result
Both versions return eight successful responses. The safeguarded trace contains the request, service and database spans under one trace ID. A long tail remains visible even though availability is 100%.
Open the exact source behind this edition. The viewer checks each file against its SHA-256 manifest and explains the decision it implements.
Choose your next step
Compare the alternatives
Understand where each pattern helps and which tradeoffs remain.
Compare approachesRun and extend it locally
Download the independent environment, run the native checks and try a specific extension.
Open the how-to guideBefore you try it
Do I need to know how to code?
Start with Run and read the comparison. The tutorial introduces the code after you have seen the behavior. The how-to guide separates a no-install route from the native developer exercise.
What happens to the experiment when I reset?
Reset discards this lab’s temporary state and cancels or terminates its pending work. These examples use invented records. No account, production data or cloud deployment is needed.
What does the browser experiment establish?
The worker creates real OpenTelemetry spans around actual timer waits. The database is a timed fixture. Eight requests teach latency arithmetic, not a production SLO window. A local HTTP service and optional Prometheus/Grafana recipe accompany the download.