fix(ddtrace/tracer): avoid tests to fail with error "non-constant format string" from upcoming Go 1.24 release

[darccio]

What does this PR do?

Upcoming Go 1.24 release introduces a new go vet check (golang/go#60529) for printf calls with non-const format and no args. This causes go test to fail to run in gotip:

❯ gotip test gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer
# gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer
# [gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer]
ddtrace/tracer/abandonedspans.go:276:11: non-constant format string in call to gopkg.in/DataDog/dd-trace-go.v1/internal/log.Warn
ddtrace/tracer/otel_dd_mappings.go:101:14: non-constant format string in call to gopkg.in/DataDog/dd-trace-go.v1/internal/log.Warn
ddtrace/tracer/slog.go:44:13: non-constant format string in call to gopkg.in/DataDog/dd-trace-go.v1/internal/log.Debug
ddtrace/tracer/slog.go:46:12: non-constant format string in call to gopkg.in/DataDog/dd-trace-go.v1/internal/log.Info
ddtrace/tracer/slog.go:48:12: non-constant format string in call to gopkg.in/DataDog/dd-trace-go.v1/internal/log.Warn
ddtrace/tracer/slog.go:50:13: non-constant format string in call to gopkg.in/DataDog/dd-trace-go.v1/internal/log.Error
ddtrace/tracer/option_test.go:341:13: non-constant format string in call to (*testing.common).Fatalf
FAIL    gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer [build failed]
FAIL

The adopted approach was refactoring internal/log API to offer:

• Debug, Info, Warn, Error functions for logging a string without arguments
• Debugf, Infof, Warnf, Errorf function for logging formatted messages with arguments

This causes a significant amount of changes across the repository, but we want to keep the API as coherent as possible. It mirrors stdlib's log API.

Motivation

Avoid unintended consequences from upcoming Go 1.24 release.

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!

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-12-17 13:53:50

Comparing candidate commit 52af2e8 in PR branch dario.castane/go-124-errors with baseline commit cd21985 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 58 metrics, 1 unstable metrics.

[hannahkm]

Could we check for the same issues in other directories (other than ddtrace/tracer)? Running gotip locally gives similar failures in our ddtrace/opentelemetry and internal/appsec, for example.

[darccio]

@hannahkm I think we'll have to apply a different approach, because our Error function kind of expects that the first string argument is usually constant:

[datadog-datadog-prod-us1]

Datadog Report

Branch report: dario.castane/go-124-errors
Commit report: e95f6c7
Test service: dd-trace-go

✅ 0 Failed, 5112 Passed, 70 Skipped, 2m 55.25s Total Time