fix(server): pre-register prometheus metrics at startup#1150
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TaylorMutch wants to merge 1 commit intomainfrom
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fix(server): pre-register prometheus metrics at startup#1150TaylorMutch wants to merge 1 commit intomainfrom
TaylorMutch wants to merge 1 commit intomainfrom
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Records openshell_server_start_time_seconds immediately after install_recorder() so /metrics returns a non-empty body from the first scrape after pod restart. metrics-exporter-prometheus 0.18 only emits a metric once a value has been recorded; describe_* alone is not sufficient. The startup gauge fixes the empty-body window while describe_* calls register HELP/TYPE metadata for request metrics so they render correctly when traffic arrives. Closes #1119
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Summary
Records
openshell_server_start_time_secondsimmediately afterinstall_recorder()so/metricsreturns a non-empty body from the first Prometheus scrape after pod restart.describe_*calls are also added for all four request metrics so their HELP/TYPE metadata renders correctly once traffic arrives.Related Issue
Closes #1119
Changes
crates/openshell-server/src/lib.rs: Addedgauge!("openshell_server_start_time_seconds")with current Unix timestamp anddescribe_counter!/describe_histogram!for the four request metrics, immediately afterinstall_recorder().crates/openshell-server/tests/metrics_preregistration.rs(new): Integration test assertinghandle.render()is non-empty and containsopenshell_server_start_time_secondsbefore any request is made.Deviations from Plan
The approved plan proposed using only
describe_*macros. Investigation revealed thatmetrics-exporter-prometheus0.18 only emits a metric inrender()once a value has been recorded — descriptions alone produce no output. The fix was updated to also record aopenshell_server_start_time_secondsgauge at startup (a standard Prometheus pattern used by most exporters). Thedescribe_*calls are retained for HELP/TYPE metadata on request metrics.Testing
mise run pre-commitpassesTests added:
crates/openshell-server/tests/metrics_preregistration.rs::metrics_are_non_empty_before_any_request— verifieshandle.render()is non-empty and contains the startup gauge before any request flows throughMultiplexedServiceChecklist
Documentation updated: