HttpURLConnection instrumentation does not mark trace as external

[meiao]

Description

When a transaction has an HTTP call using HttpURLConnection, the distributed traces for the HTTP call do show as being in the same transaction and not as a remote call.

Expected Behavior

These HTTP calls show as remotes, like calls that use Apache's HTTP client.

Steps to Reproduce

Have 2 servers with DT enabled.
From one server, make an HTTP call using HttpURLConnection to the other.
Check DT.

Your Environment

Java 16
Agent 7.2.0-SNAPSHOT
But most likely all other versions are affected.

[jasonjkeller]

It looks like this is because the httpurlconnection instrumentation doesn't utilize the newer NewRelic.getAgent().getTracedMethod().reportAsExternal API. The httpurlconnection instrumentation is ~7 years and predates the reportAsExternal API and doesn't look like it was ever updated when the API was introduced.

I think refactoring the httpurlconnection instrumentation similar to this commit (3acebd3
) so that it takes advantage of the newer reportAsExternal API should resolve the issue.

Note: There are problems with this commit that need to be fixed and tested still.

Incorrect external with existing instrumentation:

Correct external with fixed instrumentation:

[kford-newrelic]

Found that additional code refactoring and testing is required, will not be able to make the 7.8.0 release with a fix. Targeting the next available release instead.

[contentfree]

It seems like this is now broken in a different way.

In this screenshot, you can see that the external service is correctly recognized as such (small green sliver) but the time inside the external service call is not included in the external service span. (It reports as something like 40 microseconds though the request actually took nearly a minute; the time reported as Application Code in the next line is actually time spent inside HttpURLConnection.post):

Could this be related to this change?

[meiao]

We have other problems with this instrumentation and are currently working on improving it.
You can track progress in this ticket: #1378