Repository navigation
GrpcMetricsInterceptor records into a private SimpleMeterRegistry disconnected from the server registry — gRPC metrics black-holed #4826
Description
Affected version: 26.6.1
Component: GrpcMetricsInterceptor
Severity: MEDIUM (observability)
Summary
The interceptor builds its own new SimpleMeterRegistry() (the comment admits "In
production, integrate with server's meter registry"), disconnected from the global
Metrics registry the rest of the service uses. Per-method metrics are written
into call trailers rather than tagged meters.
Code
GrpcMetricsInterceptor.java:43-58 (private registry), :81-82 (trailers).
Impact
gRPC request/error/duration metrics never reach the real registry — operators see
no gRPC telemetry from this interceptor.
Suggested fix
Inject/look up the server's shared MeterRegistry; record method/status as meter
tags.
Activity
fix(#4826): publish gRPC metrics into the shared server registry with…
lvca commentedon Jun 30, 2026
Confirmed and fixed in main.
The gRPC metrics interceptor was writing into its own private meter registry that nothing scraped, so gRPC request/error/duration metrics never showed up in Prometheus, OTLP, JMX or Studio. It now publishes into the same shared server registry as the rest of the metrics, and each metric is tagged with the gRPC method (plus status code for errors and durations), so you can break telemetry down by method/status. The fix ships in the next release.
fix(#4826): publish gRPC metrics into the shared server registry with…