profiler: add enable flag to control profiler activation

profiler/options.go

@@ -111,6 +111,7 @@ type config struct {
 	logStartup           bool
 	traceConfig          executionTraceConfig
 	endpointCountEnabled bool
+	enable               bool
 }
 
 // logStartup records the configuration to the configured logger in JSON format
@@ -146,6 +147,7 @@ func logStartup(c *config) {
 		"execution_trace_size_limit": c.traceConfig.Limit,
 		"endpoint_count_enabled":     c.endpointCountEnabled,
 		"custom_profiler_label_keys": c.customProfilerLabels,
+		"enable":                     c.enable,
 	}
 	b, err := json.Marshal(info)
 	if err != nil {
@@ -208,6 +210,7 @@ func defaultConfig() (*config, error) {
 	} else {
 		c.agentURL = url.String() + "/profiling/v1/input"
 	}
+	c.enable = internal.BoolEnv("DD_PROFILING_ENABLED", true)
 	if v := os.Getenv("DD_PROFILING_UPLOAD_TIMEOUT"); v != "" {
 		d, err := time.ParseDuration(v)
 		if err != nil {

profiler/options_test.go

@@ -264,6 +264,21 @@ func TestEnvVars(t *testing.T) {
 		assert.Equal(t, "http://localhost:6218/profiling/v1/input", cfg.agentURL)
 	})
 
+	t.Run("DD_PROFILING_ENABLED", func(t *testing.T) {
+		t.Run("default", func(t *testing.T) {
+			cfg, err := defaultConfig()
+			require.NoError(t, err)
+			assert.Equal(t, true, cfg.enable)
+		})
+
+		t.Run("override", func(t *testing.T) {
+			t.Setenv("DD_PROFILING_ENABLED", "false")
+			cfg, err := defaultConfig()
+			require.NoError(t, err)
+			assert.Equal(t, false, cfg.enable)
+		})
+	})
+
 	t.Run("DD_PROFILING_UPLOAD_TIMEOUT", func(t *testing.T) {
 		t.Setenv("DD_PROFILING_UPLOAD_TIMEOUT", "3s")
 		cfg, err := defaultConfig()

profiler/profiler.go

@@ -54,6 +54,9 @@ func Start(opts ...Option) error {
 	if err != nil {
 		return err
 	}
+	if !p.cfg.enable {
+		return nil
+	}
 	activeProfiler = p
 	activeProfiler.run()
 	traceprof.SetProfilerEnabled(true)

profiler/profiler_test.go

@@ -82,6 +82,20 @@ func TestStart(t *testing.T) {
 		mu.Unlock()
 	})
 
+	t.Run("dd_profiling_not_enabled", func(t *testing.T) {
+		t.Setenv("DD_PROFILING_ENABLED", "false")
+		if err := Start(); err != nil {
+			t.Fatal(err)
+		}
+		defer Stop()
+
+		mu.Lock()
+		// if DD_PROFILING_ENABLED is false, the profiler should not be started even if Start() is called
+		// So we should not have an activeProfiler
+		assert.Nil(t, activeProfiler)
+		mu.Unlock()
+	})
+
 	t.Run("options", func(t *testing.T) {
 		if err := Start(); err != nil {
 			t.Fatal(err)