[TEP-0089] Enable SPIRE for signing taskrun results in alpha.

Breaking down PR tektoncd#4759 originally proposed by @pxp928 to address TEP-0089 according @lumjjb suggestions. Plan for breaking down PR is PR 1.1: api PR 1.2: entrypointer (+cmd line + test/entrypointer) Entrypoint takes results and signs the results (termination message). PR 1.3: reconciler + pod + cmd/controller + integration tests Controller will verify the signed result. This commit corresponds to 1.3 above.

Signed-off-by: jagathprakash <31057312+jagathprakash@users.noreply.github.com>

pkg/apis/config/feature_flags.go

@@ -146,7 +146,7 @@ func GetFeatureFlagsConfigName() string {
 	return "feature-flags"
 }
 
-func GetEnforceNonfalsifiabilityValues() []string {
+func getEnforceNonfalsifiabilityValues() []string {
 	return []string{EnforceNonfalsifiabilityNone, EnforceNonfalsifiabilityWithSpire}
 }
 
@@ -242,7 +242,7 @@ func NewFeatureFlagsFromMap(cfgMap map[string]string) (*FeatureFlags, error) {
 		if err := setFeature(enableCustomTasks, DefaultEnableCustomTasks, &tc.EnableCustomTasks); err != nil {
 			return nil, err
 		}
-		if err := setStringFeature(enforceNonfalsifiability, DefaultEnforceNonfalsifiability, GetEnforceNonfalsifiabilityValues(), &tc.EnforceNonfalsifiability); err != nil {
+		if err := setStringFeature(enforceNonfalsifiability, DefaultEnforceNonfalsifiability, getEnforceNonfalsifiabilityValues(), &tc.EnforceNonfalsifiability); err != nil {
 			return nil, err
 		}
 	}

pkg/spire/controller.go

@@ -53,7 +53,7 @@ func OnStore(ctx context.Context, logger *zap.SugaredLogger) func(name string, v
 		if name == config.GetSpireConfigName() {
 			cfg, ok := value.(*spireconfig.SpireConfig)
 			if !ok {
-				logger.Error("Failed to do type insertion for extracting metrics config")
+				logger.Error("Failed to do type insertion for extracting SPIRE config")
 				return
 			}
 			controllerAPIClient := GetControllerAPIClient(ctx)
@@ -70,7 +70,7 @@ func GetControllerAPIClient(ctx context.Context) ControllerAPIClient {
 		logging.FromContext(ctx).Errorf("Unable to fetch client from context.")
 		return nil
 	}
-	return untyped.(*spireControllerAPIClient)
+	return untyped.(ControllerAPIClient)
 }
 
 func withControllerClient(ctx context.Context, cfg *rest.Config) context.Context {