all: replace internal/telemetry by internal/newtelemetry

[eliottness]

What does this PR do?

This PR replace the old telemetry client with the new one. It does, in order:

• git rm -r internal/telemetry
• git mv internal/newtelemetry internal/telemetry
• Apply changes on the parts of the API that changed signicantly:
  • The way to start a new telemetry client is different, no more telemetry.ApplyOps
  • The API for metrics has been changed for better performances
• Rework the internal/telemetry/telemetrytest package because it was not using github.com/stretchr/testify/mock correctly (like, not at all)
• Update a literral TON of tests that were using the horrible telemetrytest API

Motivation

Better telemetry and support for telemetry metrics in the customer request hot path.
RFC: https://docs.google.com/document/d/1C3xoTZHQZNQ-Jr1w5mMThIkpHNW_4qKRf-J5CNi7G-k/edit?pli=1&tab=t.0#heading=h.88xvn2cvs9dt

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]

Datadog Report

Branch report: eliott.bouhana/remove-oldtelemetry
Commit report: 51acfaa
Test service: dd-trace-go

❌ 8 Failed (0 Known Flaky), 3814 Passed, 72 Skipped, 2m 34.96s Total Time

❌ Failed Tests (8)

This report shows up to 5 failed tests.

• TestIntegrationInfo - gopkg.in/DataDog/dd-trace-go.v1/contrib/internal/telemetrytest - Details

  Expand for error

   Failed
   
   === RUN   TestIntegrationInfo
   panic: 
   assert: mock: I don't know what to return because the method call was unexpected.
   	Either do Mock.On("Flush").Return(...) first, or remove the Flush() call.
   	This method was unexpected:
   		Flush()
   		
   	at: [/home/runner/work/dd-trace-go/dd-trace-go/internal/telemetry/telemetrytest/mock.go:82 /home/runner/work/dd-trace-go/dd-trace-go/internal/telemetry/globalclient.go:50 /opt/hostedtoolcache/go/1.22.11/x64/src/runtime/asm_amd64.s:1695]
   ...
  

• TestAssessSource - gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer - Details

  Expand for error

   Failed
   
   === RUN   TestAssessSource
   --- FAIL: TestAssessSource (0.00s)
  

• TestAssessSource/invalid-ot - gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer - Details

  Expand for error

   Failed
   
   === RUN   TestAssessSource/invalid-ot
       otel_dd_mappings_test.go:52: 
           	Error Trace:	/home/runner/work/dd-trace-go/dd-trace-go/ddtrace/tracer/otel_dd_mappings_test.go:52
           	Error:      	Should not be zero, but was 0
           	Test:       	TestAssessSource/invalid-ot
       --- FAIL: TestAssessSource/invalid-ot (0.00s)
  

• TestOnRemoteConfigUpdate - gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer - Details

  Expand for error

   Failed
   
   === RUN   TestOnRemoteConfigUpdate
   --- FAIL: TestOnRemoteConfigUpdate (0.00s)
  

• TestOnRemoteConfigUpdate/RC_sampling_rate_=_0.5_is_applied_and_can_be_reverted - gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer - Details

  Expand for error

   Failed
   
   === RUN   TestOnRemoteConfigUpdate/RC_sampling_rate_=_0.5_is_applied_and_can_be_reverted
       --- FAIL: TestOnRemoteConfigUpdate/RC_sampling_rate_=_0.5_is_applied_and_can_be_reverted (0.00s)
   panic: 
   assert: mock: I don't know what to return because the method call was unexpected.
   	Either do Mock.On("Count").Return(...) first, or remove the Count() call.
   	This method was unexpected:
   		Count(transport.Namespace,string,[]string)
   		0: "civisibility"
   ...
  

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-31 16:52:48

Comparing candidate commit 9992be0 in PR branch eliott.bouhana/remove-oldtelemetry with baseline commit 681eae1 in branch eliott.bouhana/newtelemetry.

Found 0 performance improvements and 5 performance regressions! Performance is the same for 54 metrics, 0 unstable metrics.

scenario:BenchmarkOTelApiWithCustomTags/otel_api-24

• 🟥 allocated_mem [+379 bytes; +390 bytes] or [+7.827%; +8.051%]
• 🟥 allocations [+6; +6] or [+13.953%; +13.953%]
• 🟥 execution_time [+249.607ns; +293.593ns] or [+3.438%; +4.044%]

scenario:BenchmarkSetTagString-24

• 🟥 execution_time [+3.531ns; +5.169ns] or [+3.143%; +4.601%]

scenario:BenchmarkTracerAddSpans-24

• 🟥 execution_time [+130.422ns; +159.578ns] or [+3.390%; +4.148%]