Function Test_ContextTemplate_ConcurrentRegistration

log/context_test.go:347–399

Test_ContextTemplate_ConcurrentRegistration exercises the lock split between the atomic-pointer read path and the mutex-guarded rebuild path. It must be run with -race to be meaningful. The test is order-independent: it registers its own "tenant" tag rather than relying on a sibling test having alr

(t *testing.T)

// than relying on a sibling test having already done so, which matters when
// the test runner is invoked with -shuffle=on.
func Test_ContextTemplate_ConcurrentRegistration(t *testing.T) {
	t.Cleanup(func() { MustSetContextTemplate(ContextConfig{}) })

	require.NoError(t, RegisterContextTag("tenant", func(output Buffer, _ any, _ *ContextData, _ string) (int, error) {
		return output.WriteString("acme")
	}))
	require.NoError(t, SetContextTemplate(ContextConfig{Format: "[${tenant}]"}))

	const goroutines = 8
	const iterations = 200

	var wg sync.WaitGroup
	wg.Add(goroutines * 3)

	register := func(id int) {
		defer wg.Done()
		for range iterations {
			//nolint:errcheck // race-stress test intentionally ignores transient errors
			_ = RegisterContextTag("tenant", func(output Buffer, _ any, _ *ContextData, _ string) (int, error) {
				return output.WriteString("acme")
			})
			_ = id
		}
	}
	reformat := func() {
		defer wg.Done()
		for range iterations {
			//nolint:errcheck // race-stress test intentionally ignores transient errors
			_ = SetContextTemplate(ContextConfig{Format: "[${tenant}]"})
		}
	}
	emit := func() {
		defer wg.Done()
		for range iterations {
			tmpl := contextTemplate.Load()
			if tmpl == nil {
				continue
			}
			buf := bytebufferpool.Get()
			//nolint:errcheck // race-stress test intentionally ignores transient errors
			_ = tmpl.Execute(buf, context.Background(), &ContextData{})
			bytebufferpool.Put(buf)
		}
	}

	for i := range goroutines {
		go register(i)
		go reformat()
		go emit()
	}

	wg.Wait()
}

func Benchmark_ContextTemplate_Execute(b *testing.B) {
	tmpl, err := logtemplate.Build[any, ContextData]("[${requestid}] ", map[string]ContextTagFunc{