envoyproxy/envoy

Envoy /stats/prometheus?filter works only with statsd metrics

Open

#10,927 opened on Apr 24, 2020

View on GitHub
 (6 comments) (1 reaction) (0 assignees)C++ (5,373 forks)batch import
area/statshelp wanted

Repository metrics

Stars
 (27,997 stars)
PR merge metrics
 (Avg merge 8d) (378 merged PRs in 30d)

Description

curl  'localhost:9901/stats/prometheus?filter=runtime.load_error'
# TYPE envoy_runtime_load_error counter
envoy_runtime_load_error{} 0

I was expecting envoy_runtime_load_error to be used when filtering metrics on the prometheus stats endpoint, but filtering on it returns nothing. Only statsd runtime.load_error works.

This forces a weird mapping on the monitoring side. We have to maintain a map of statsd:prometheus metric names or re-implement the reverse transformation on the monitoring side.

I'm willing to work on this if it's considered a bug and not expected behaviour. What I think is happening is that the filtering is done before the statsd->prometheus metric transformation -- and should be moved after.

Contributor guide

Research direction
Trace the code path for /stats/prometheus endpoint, focusing on the filtering logic and metric name transformation. Identify where the filter is applied before the statsd to prometheus metric name conversion, then propose moving the filter after the conversion.
Tech stack
cpp
Domain
networkingapi
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++Envoy internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70