contrib/google.golang.org/protobuf: Add schema tracking instrumentation

[piochelepiotr]

What does this PR do?

Adds Protobuf instrumentation to Go, extracting Protobuf schemas. This feature helps to track usage of schemas by all Golang applications.

Motivation

Reviewer's Checklist

• [ ] Changed code has unit tests for its functionality at or near 100% coverage.
• [ ] System-Tests covering this feature have been added and enabled with the va.b.c-dev version tag.
• [ ] There is a benchmark for any new code, or changes to existing code.
• [ ] If this interacts with the agent in a new way, a system test has been added.
• [ ] Add an appropriate team label so this PR gets put in the right place for the release notes.
• [ ] Non-trivial go.mod changes, e.g. adding new modules, are reviewed by @DataDog/dd-trace-go-guild.
• [ ] For internal contributors, a matching PR should be created to the v2-dev branch and reviewed by @DataDog/apm-go.

Unsure? Have a question? Request a review!

[datadog-datadog-prod-us1[bot]]

Datadog Report

Branch report: piotr-wolski/add-protobuf-instrumentation Commit report: 6a274e4 Test service: dd-trace-go

:white_check_mark: 0 Failed, 5350 Passed, 72 Skipped, 2m 56.93s Total Time

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2025-02-25 12:26:21

Comparing candidate commit b00c8f3aeb597850096824836744ef7d4526ac64 in PR branch piotr-wolski/add-protobuf-instrumentation with baseline commit 386c125b024bfa7be093f4f32d6b3c84e46960ce in branch main.

Found 1 performance improvements and 3 performance regressions! Performance is the same for 57 metrics, 1 unstable metrics.

scenario:BenchmarkInjectW3C-24

• 🟥 execution_time [+185.618ns; +208.582ns] or [+4.578%; +5.145%]

scenario:BenchmarkSetTagString-24

• 🟥 execution_time [+3.666ns; +7.434ns] or [+3.222%; +6.535%]

scenario:BenchmarkSetTagStringer-24

• 🟥 execution_time [+4.524ns; +8.856ns] or [+3.106%; +6.080%]

scenario:BenchmarkStartRequestSpan-24

• 🟩 execution_time [-10.885ns; -9.635ns] or [-2.446%; -2.165%]

[darccio]

@piochelepiotr As part of our upcoming release, we are reviewing all in-flight PRs. Please consider closing it or rebasing to v2-dev if you want to merge it for the next release after v2.0.0.

If you need. this in v1, please apply the requested changes, and create a PR for v2-dev too.

[darccio]

@piochelepiotr Is this PR still relevant? Thanks!