fix: default RevertGithubDNSExperiment to true when flags can't be fetched

apiclient.go

@@ -123,7 +123,7 @@ func (apiclient *ApiClient) getGlobalFeatureFlags() GlobalFeatureFlags {
 
 	u, err := url.Parse(apiclient.APIURL)
 	if err != nil {
-		return GlobalFeatureFlags{}
+		return defaultGlobalFeatureFlags()
 	}
 
 	u.Path = path.Join(u.Path, "global-feature-flags")
@@ -138,27 +138,27 @@ func (apiclient *ApiClient) getGlobalFeatureFlags() GlobalFeatureFlags {
 
 	if err != nil {
 		fmt.Println("Error creating request:", err)
-		return GlobalFeatureFlags{}
+		return defaultGlobalFeatureFlags()
 	}
 
 	resp, err := apiclient.Client.Do(req)
 
 	if err != nil {
 		fmt.Println("Error sending request:", err)
-		return GlobalFeatureFlags{}
+		return defaultGlobalFeatureFlags()
 	}
 
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		fmt.Println("Error reading response body:", err)
-		return GlobalFeatureFlags{}
+		return defaultGlobalFeatureFlags()
 	}
 
 	var globalFeatureFlags GlobalFeatureFlags
 	err = json.Unmarshal(body, &globalFeatureFlags)
 	if err != nil {
 		fmt.Println("Error unmarshalling response body:", err)
-		return GlobalFeatureFlags{}
+		return defaultGlobalFeatureFlags()
 	}
 
 	return globalFeatureFlags

apiclient_test.go

@@ -100,3 +100,47 @@ func Test_getGithubMetaDomains_ErrorAfterRetries(t *testing.T) {
 		t.Fatalf("server called %d times, want 3", got)
 	}
 }
+
+func Test_getGlobalFeatureFlags(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/v1/global-feature-flags" {
+			fmt.Fprint(w, `not json`)
+			return
+		}
+		fmt.Fprint(w, `{"agent_type":"agent-oss","revert_github_dns_experiment":false}`)
+	}))
+	defer server.Close()
+
+	closedServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
+	closedServer.Close()
+
+	tests := []struct {
+		name   string
+		apiURL string
+		want   GlobalFeatureFlags
+	}{
+		{name: "fetched flags", apiURL: server.URL + "/v1", want: GlobalFeatureFlags{AgentType: AgentTypeOSS}},
+		{name: "invalid url", apiURL: "%zz", want: defaultGlobalFeatureFlags()},
+		{name: "request error", apiURL: closedServer.URL, want: defaultGlobalFeatureFlags()},
+		{name: "invalid response", apiURL: server.URL + "/other", want: defaultGlobalFeatureFlags()},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			apiclient := &ApiClient{Client: newTestHTTPClient(), APIURL: tt.apiURL}
+
+			if got := apiclient.getGlobalFeatureFlags(); got != tt.want {
+				t.Fatalf("getGlobalFeatureFlags() = %+v, want %+v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_GetGlobalFeatureFlags_DefaultsWhenUninitialized(t *testing.T) {
+	savedManager := globalManager
+	globalManager = nil
+	defer func() { globalManager = savedManager }()
+
+	if got := GetGlobalFeatureFlags(); !got.RevertGithubDNSExperiment {
+		t.Fatalf("GetGlobalFeatureFlags() = %+v, want RevertGithubDNSExperiment true", got)
+	}
+}

global_feature_flags.go

@@ -36,7 +36,7 @@ func InitGlobalFeatureFlags(apiURL string, apiClient *ApiClient) {
 	globalOnce.Do(func() {
 		globalManager = &GlobalFeatureFlagManager{
 			apiURL:    apiURL,
-			flags:     GlobalFeatureFlags{}, // Default values
+			flags:     defaultGlobalFeatureFlags(),
 			apiClient: apiClient,
 		}
 		// Fetch initial flags and handle errors gracefully
@@ -68,10 +68,10 @@ func RefreshGlobalFeatureFlags() error {
 }
 
 // GetGlobalFeatureFlags returns the current global feature flags.
-// This method never returns nil. It returns a default-initialized struct if manager is not initialized.
+// This method never returns nil. It returns default flags if manager is not initialized.
 func GetGlobalFeatureFlags() GlobalFeatureFlags {
 	if globalManager == nil {
-		return GlobalFeatureFlags{} // Return default-initialized struct
+		return defaultGlobalFeatureFlags()
 	}
 	globalManager.mutex.RLock()
 	defer globalManager.mutex.RUnlock()
@@ -87,3 +87,10 @@ func IsCustomDetectionRulesEnabled() bool {
 	flags := GetGlobalFeatureFlags()
 	return flags.EnableCustomDetectionRules
 }
+
+// defaultGlobalFeatureFlags returns the flags used when they could not be fetched.
+func defaultGlobalFeatureFlags() GlobalFeatureFlags {
+	return GlobalFeatureFlags{
+		RevertGithubDNSExperiment: true,
+	}
+}