[v10.0.x] Licensing: Pass func to update env variables when starting plugin (#74679)

* Licensing: Pass func to update env variables when starting plugin (#74620)

(cherry picked from commit 5e0b20266e)

pkg/plugins/manager/loader/initializer/initializer.go

@@ -39,7 +39,11 @@ func (i *Initializer) Initialize(ctx context.Context, p *plugins.Plugin) error {
 			return fmt.Errorf("could not find backend factory for plugin")
 		}
 
-		if backendClient, err := backendFactory(p.ID, p.Logger(), i.envVars(p)); err != nil {
+		envFunc := func() []string {
+			return i.envVars(p)
+		}
+
+		if backendClient, err := backendFactory(p.ID, p.Logger(), envFunc); err != nil {
 			return err
 		} else {
 			p.RegisterClient(backendClient)

pkg/plugins/manager/loader/initializer/initializer_test.go

@@ -465,7 +465,7 @@ type fakeBackendProvider struct {
 }
 
 func (f *fakeBackendProvider) BackendFactory(_ context.Context, _ *plugins.Plugin) backendplugin.PluginFactoryFunc {
-	return func(_ string, _ log.Logger, _ []string) (backendplugin.Plugin, error) {
+	return func(_ string, _ log.Logger, _ func() []string) (backendplugin.Plugin, error) {
 		return f.plugin, nil
 	}
 }

pkg/plugins/manager/loader/loader_test.go

@@ -1045,7 +1045,7 @@ func TestLoader_Load_SkipUninitializedPlugins(t *testing.T) {
 		procPrvdr := fakes.NewFakeBackendProcessProvider()
 		// Cause an initialization error
 		procPrvdr.BackendFactoryFunc = func(ctx context.Context, p *plugins.Plugin) backendplugin.PluginFactoryFunc {
-			return func(pluginID string, _ log.Logger, _ []string) (backendplugin.Plugin, error) {
+			return func(pluginID string, _ log.Logger, _ func() []string) (backendplugin.Plugin, error) {
 				if pluginID == "test-datasource" {
 					return nil, fmt.Errorf("failed to initialize")
 				}