[v9.5.x] Licensing: Pass func to update env variables when starting plugin (#74681)

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

(cherry picked from commit 5e0b20266e)

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

@@ -37,7 +37,10 @@ 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 {
+		// this will ensure that the env variables are calculated every time a plugin is started
+		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

@@ -422,7 +422,7 @@ 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
 	}
 }