HTTP Automatic Instrumentation Enhancement for network phases breakdown via HTTP Span Events

[surbhiia]

Related Proposals
• Semantic Conventions: open-telemetry/semantic-conventions#2827
• OkHttp Manual Instrumentation Library: open-telemetry/opentelemetry-java-instrumentation#14835

Proposed Changes

• OkHttp3 Automatic Instrumentation
  • Leverage the EventListener implementation from the manual instrumentation proposal to enhance automatic instrumentation
• HttpURLConnection Automatic Instrumentation
  • Enhance existing HttpUrlReplacements class to capture similar timing events (whichever possible - For example it would be difficult to capture dns, tls and tcp timestamps separately but total connection duration can be captured)

[fractalwrench]

I think it would be useful to have the ability to capture this info. At Embrace we've also talked about covering the serialization/deserialization step for JSON payloads, which I figure is what most folks are using for HTTP requests on Android. OkHttp is the de facto standard so I'd be fine with HttpUrlConnection remaining as it is.

One question to discuss is when to capture this information, and specifically whether it makes sense to do so for every request in an app + whether library consumers would want to disable certain parts (e.g. DNS/TLS). We've also toyed with the idea of enabling this instrumentation just for certain domains or for a limited number of requests to reduce the size of the captured telemetry.

[bidetofevil]

I wouldn't worry about Http(s)UrlConnection. That API is unwieldy, and you can get some amount of detail for the request lifecycle stuff, but it could be a lot of work to get right with little utility.

And the fact that the Android implementation doesn't support HTTP/2 means no one should really use it to make regular HTTP requests. It's fine for streaming or maintaining a persistent connection for server sent events or something, but this instrumentation doesn't support that anyway. I would just implement this for OkHttp and leave it at that.