Enable prepare data plugins behind a feature flag

Author: rahulgurnani

cmd/epp/runner/runner.go

@@ -504,8 +504,9 @@ func (r *Runner) parseConfigurationPhaseTwo(ctx context.Context, rawConfig *conf
 
 	// Add requestControl plugins
 	r.requestControlConfig.AddPlugins(handle.GetAllPlugins()...)
+
 	// Sort prepare data plugins in DAG order (topological sort). Also check prepare data plugins for cycles.
-	if r.requestControlConfig.PrepareDataPluginGraph() != nil {
+	if r.requestControlConfig.PrepareDataPluginGraph(r.featureGates[datalayer.PrepareDataPluginsFeatureGate]) != nil {
 		return nil, errors.New("failed to load the configuration - prepare data plugins have cyclic dependencies")
 	}
 

pkg/epp/datalayer/factory.go

@@ -26,7 +26,8 @@ import (
 )
 
 const (
-	FeatureGate = "dataLayer"
+	FeatureGate                   = "dataLayer"
+	PrepareDataPluginsFeatureGate = "prepareDataPlugins"
 )
 
 // PoolInfo represents the DataStore information needed for endpoints.

pkg/epp/requestcontrol/request_control_config.go

@@ -107,7 +107,11 @@ func (c *Config) AddPlugins(pluginObjects ...plugins.Plugin) {
 
 // PrepareDataPluginGraph creates data dependency graph and sorts the plugins in topological order.
 // If a cycle is detected, it returns an error.
-func (c *Config) PrepareDataPluginGraph() error {
+func (c *Config) PrepareDataPluginGraph(enablePrepareDataPlugins bool) error {
+	if !enablePrepareDataPlugins {
+		c.prepareDataPlugins = []PrepareDataPlugin{}
+		return nil
+	}
 	dag := buildDAG(c.prepareDataPlugins)
 	plugins, err := sortPlugins(dag, c.prepareDataPlugins)
 	if err != nil {