feat: Support apiKey for GO Feature Flag relay proxy v1.7.0 (open-feature#166)

Signed-off-by: Thomas Poignant <[email protected]>

Author: thomaspoignant

providers/go-feature-flag/pkg/provider.go

@@ -21,6 +21,7 @@ type Provider struct {
 	httpClient            HTTPClient
 	endpoint              string
 	goFeatureFlagInstance *client.GoFeatureFlag
+	apiKey                string
 }
 
 // HTTPClient is a custom interface to be able to override it by any implementation
@@ -64,6 +65,7 @@ func NewProvider(options ProviderOptions) (*Provider, error) {
 	}
 
 	return &Provider{
+		apiKey:     options.APIKey,
 		endpoint:   options.Endpoint,
 		httpClient: httpClient,
 	}, nil
@@ -276,6 +278,9 @@ func evaluateWithRelayProxy[T model.JsonType](provider *Provider, ctx context.Co
 		}
 	}
 	goffRequest.Header.Set("Content-Type", "application/json")
+	if provider.apiKey != "" {
+		goffRequest.Header.Set("Authorization", fmt.Sprintf("Bearer %s", provider.apiKey))
+	}
 
 	response, err := provider.httpClient.Do(goffRequest)
 	if err != nil {
@@ -298,6 +303,27 @@ func evaluateWithRelayProxy[T model.JsonType](provider *Provider, ctx context.Co
 		}
 	}
 
+	if response.StatusCode == http.StatusUnauthorized {
+		return model.GenericResolutionDetail[T]{
+			Value: defaultValue,
+			ProviderResolutionDetail: of.ProviderResolutionDetail{
+				ResolutionError: of.NewGeneralResolutionError(
+					"invalid token used to contact GO Feature Flag relay proxy instance"),
+				Reason: of.ErrorReason,
+			},
+		}
+	}
+	if response.StatusCode >= http.StatusBadRequest {
+		return model.GenericResolutionDetail[T]{
+			Value: defaultValue,
+			ProviderResolutionDetail: of.ProviderResolutionDetail{
+				ResolutionError: of.NewGeneralResolutionError(
+					"unexpected answer from the relay proxy"),
+				Reason: of.ErrorReason,
+			},
+		}
+	}
+
 	var evalResponse model.EvalResponse[T]
 	err = json.Unmarshal(responseStr, &evalResponse)
 	if err != nil {

providers/go-feature-flag/pkg/provider_options.go

@@ -16,4 +16,10 @@ type ProviderOptions struct {
 	// GOFeatureFlagConfig is the configuration struct for the GO Feature Flag module.
 	// If not nil we will launch the provider using the GO Feature Flag module.
 	GOFeatureFlagConfig *ffclient.Config
+
+	// APIKey  (optional) If the relay proxy is configured to authenticate the requests, you should provide
+	// an API Key to the provider. Please ask the administrator of the relay proxy to provide an API Key.
+	// (This feature is available only if you are using GO Feature Flag relay proxy v1.7.0 or above)
+	// Default: null
+	APIKey string
 }

providers/go-feature-flag/pkg/provider_test.go

@@ -20,6 +20,14 @@ type mockClient struct{}
 func (m *mockClient) Do(req *http.Request) (*http.Response, error) {
 	mockPath := "../testutils/mock_responses/%s.json"
 	flagName := strings.Replace(strings.Replace(req.URL.Path, "/v1/feature/", "", -1), "/eval", "", -1)
+
+	if flagName == "unauthorized" {
+		return &http.Response{
+			StatusCode: http.StatusUnauthorized,
+			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
+		}, nil
+	}
+
 	content, err := os.ReadFile(fmt.Sprintf(mockPath, flagName))
 	if err != nil {
 		content, _ = os.ReadFile(fmt.Sprintf(mockPath, "flag_not_found"))
@@ -65,6 +73,27 @@ func TestProvider_BooleanEvaluation(t *testing.T) {
 		args args
 		want of.BooleanEvaluationDetails
 	}{
+		{
+			name: "unauthorized flag",
+			args: args{
+				flag:         "unauthorized",
+				defaultValue: false,
+				evalCtx:      defaultEvaluationCtx(),
+			},
+			want: of.BooleanEvaluationDetails{
+				Value: false,
+				EvaluationDetails: of.EvaluationDetails{
+					FlagKey:  "unauthorized",
+					FlagType: of.Boolean,
+					ResolutionDetail: of.ResolutionDetail{
+						Variant:      "",
+						Reason:       of.ErrorReason,
+						ErrorCode:    of.GeneralCode,
+						ErrorMessage: "invalid token used to contact GO Feature Flag relay proxy instance",
+					},
+				},
+			},
+		},
 		{
 			name: "should resolve a valid boolean flag with TARGETING_MATCH reason",
 			args: args{