app/plugin: add product middleware and enable products register their routers (#20374)

app/plugin.go

@@ -17,6 +17,7 @@ import (
 	"sync"
 
 	"github.com/blang/semver"
+	"github.com/gorilla/mux"
 	svg "github.com/h2non/go-is-svg"
 	"github.com/pkg/errors"
 
@@ -37,6 +38,28 @@ type pluginSignaturePath struct {
 	signaturePath string
 }
 
+type routerService struct {
+	mu        sync.Mutex
+	routerMap map[string]*mux.Router
+}
+
+func newRouterService() *routerService {
+	return &routerService{
+		routerMap: make(map[string]*mux.Router),
+	}
+}
+
+func (rs *routerService) RegisterRouter(productID string, sub *mux.Router) {
+	rs.mu.Lock()
+	defer rs.mu.Unlock()
+	rs.routerMap[productID] = sub
+}
+
+func (rs *routerService) getHandler(productID string) (http.Handler, bool) {
+	handler, ok := rs.routerMap[productID]
+	return handler, ok
+}
+
 // GetPluginsEnvironment returns the plugin environment for use if plugins are enabled and
 // initialized.
 //