micrometer-metrics/micrometer

Document how to customize tags in micrometer-java11 HttpClient instrumentation

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#4962 opened on Apr 14, 2024

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doc-updatehelp wanted

Description

Currently my company is transitioning to the Quarkus ecosystem, we've found the integration with Micrometer nothing less than amazing. However, we must continue supporting applications that rely on other frameworks and various external SDKs. Our goal is to standardize metrics across these different libraries and frameworks.

Quarkus provides excellent metrics instrumentation for http_client_* using the microprofile-rest-client, as you can see the result below:

# HELP http_client_requests_seconds  
# TYPE http_client_requests_seconds summary
http_client_requests_seconds_count{clientName="stage.code.quarkus.io", method="GET", outcome="SUCCESS", status="200", uri="/extensions",} 4.0
http_client_requests_seconds_sum{clientName="stage.code.quarkus.io", method="GET", outcome="SUCCESS", status="200", uri="/extensions",} 0.862757042
# HELP http_client_requests_seconds_max  
# TYPE http_client_requests_seconds_max gauge
http_client_requests_seconds_max{clientName="stage.code.quarkus.io", method="GET", outcome="SUCCESS", status="200", uri="/extensions",} 0.525936375

However, using micrometer-java11, the metrics are slightly different, lacking the clientName tag:

# HELP http_client_requests_seconds Timer for JDK's HttpClient
# TYPE http_client_requests_seconds summary
http_client_requests_seconds_count{method="GET", outcome="SUCCESS", status="200", uri="/extensions",} 4.0
http_client_requests_seconds_sum{method="GET", outcome="SUCCESS", status="200", uri="/extensions",} 1.301264958
# HELP http_client_requests_seconds_max Timer for JDK's HttpClient
# TYPE http_client_requests_seconds_max gauge
http_client_requests_seconds_max{method="GET", outcome="SUCCESS", status="200", uri="/extensions",} 0.570812834

Despite exploring the library, I have not found a way to customize micrometer-java11 to mirror the clientName tag functionality. I am aware of the uriMapper capability to customize the uri value.

Here are my questions:

  1. What approach would you recommend for identifying the client or host in external requests?
  2. Could custom metrics be a viable solution to this challenge?
  3. Would you be interested in a pull request that introduces custom tags to micrometer-java11?

Contributor guide

Tech stack
java
Domain
observabilitybackend
Issue type
documentation
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
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.
needs investigation
Prerequisites
JavaMicrometerHTTP Client instrumentation
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the micrometer java11 module's existing tag customization capabilities. Review the source code at micrometer java11/src/main/java/io/micrometer/core/instrument/binder/jdk/HttpClientMetrics.java and related classes. Examine the uriMapper pattern and determine how to support custom tags like clientName. Look at existing documentation in the micrometer docs and any relevant discussions in issue comments. Consider proposing a new tag provider interface or documenting how to extend the existing tag setup.