Add Instrumentation (metric) for net/http

[victoraugustolls]

Background

Package Link: net/http

stdlib http client.

Proposed Solution

Collect http.client.duration metric from the stdlib http client. Currently I'm using a custom RoundTripper that calls the otelhttp tracing RoundTripper, and I think it would be nice if this was inside the contrib. If agreed, I can open a PR for it!

I see something similar was done in #427 , but it was unfortunately closed! That makes me think that this might not be desired? This is why I'm asking in advance. Thanks!

Metrics

Instruments

• http.client.duration: measure the duration of the outbound HTTP request
  • type: Histogram
  • unit: milliseconds
  • description: measure the duration of the outbound HTTP request

Prior Art

• This is a metric defined in the specs. Previous PR here: Add metrics for otelhttp client #427 .

Tasks

• Code complete:
  • Comprehensive unit tests.
  • End-to-end integration tests.
  • Tests all passing.
  • Instrumentation functionality verified.
• Documented
  • Added to the OpenTelemetry Registry
  • README included for the module describing high-level purpose.
  • Complete documentation of all public API including package documentation.
  • Instrumentation documentation updated.
• Examples
  • Dockerfile file to build example application.
  • docker-compose.yml to run example in a docker environment to demonstrate instrumentation.

[MrAlias]

In accordance with the new instrumentation policy hosting guidelines I'm closing this.

[vmihailenco]

Are we supposed to fork otelhttp to add metrics?

[victoraugustolls]

Sorry @MrAlias , but I don't quite follow. Being a standard library instrumentation, isn't this repo the right place to put it? I didn't find a good reason for not contributing for it here. Sorry if I missed something!

[MrAlias]

Ah, yeah. Closing was a mistake given we already host this instrumentation.

[victoraugustolls]

@MrAlias No worries! So I'm guessing this is a ok for developing this? If that's the case, I can work on it!

[tonglil]

Personally I feel like that kind of information is critical to the instrumentation. As far as I can tell, the otelhttp instrumentation is mostly barebones at the moment and only records HTTP GET/POST/etc, like without parameterized http.url and http.target attributes that I feel like are needed.

Would love to see this data @victoraugustolls!