Support CORS in APIServer & handler ErrServerClosed (#1107)

* Support CORS in APIServer & handler ErrServerClosed

* Fix mod inconsistency

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/fatih/color v1.15.0
 	github.com/fsnotify/fsnotify v1.6.0
 	github.com/go-chi/chi/v5 v5.0.8
+	github.com/go-chi/cors v1.2.1
 	github.com/go-logr/zapr v1.2.4
 	github.com/go-task/slim-sprig v2.20.0+incompatible
 	github.com/go-zookeeper/zk v1.0.3

go.sum

@@ -245,6 +245,8 @@ github.com/gin-gonic/gin v1.6.3 h1:ahKqKTFpO5KTPHxWZjEdPScmYaGtLo8Y4DMHoEsnp14=
 github.com/gin-gonic/gin v1.6.3/go.mod h1:75u5sXoLsGZoRN5Sgbi1eraJ4GU3++wFwWzhwvtwp4M=
 github.com/go-chi/chi/v5 v5.0.8 h1:lD+NLqFcAi1ovnVZpsnObHGW4xb4J8lNmoYVfECH1Y0=
 github.com/go-chi/chi/v5 v5.0.8/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
+github.com/go-chi/cors v1.2.1 h1:xEC8UT3Rlp2QuWNEr4Fs/c2EAGVKBwy/1vHx3bppil4=
+github.com/go-chi/cors v1.2.1/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
 github.com/go-errors/errors v1.0.1/go.mod h1:f4zRHt4oKfwPJE5k8C9vpYG+aDHdBFUsgrm6/TyX73Q=
 github.com/go-errors/errors v1.4.2 h1:J6MZopCL4uSllY1OfXM374weqZFFItUbrImctkmUxIA=
 github.com/go-errors/errors v1.4.2/go.mod h1:sIVyrIiJhuEF+Pj9Ebtd6P/rEYROXFi3BopGUQ5a5Og=

pkg/api/dynamicmux.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
+	"github.com/go-chi/cors"
 
 	"github.com/megaease/easegress/v2/pkg/logger"
 )
@@ -84,6 +85,10 @@ func (m *dynamicMux) reloadAPIs() {
 		router.Use(m.basicAuth("easegress-basic-auth", m.server.opt.BasicAuth))
 	}
 
+	// For access from browser.
+	cors := cors.New(cors.Options{})
+	router.Use(cors.Handler)
+
 	for _, apiGroup := range apiGroups {
 		for _, api := range apiGroup.Entries {
 			pathV1 := APIPrefixV1 + api.Path

pkg/api/server.go

@@ -109,7 +109,7 @@ func MustNewServer(opt *option.Options, cls cluster.Cluster, super *supervisor.S
 			logger.Infof("api server running in %s", opt.APIAddr)
 			err = s.server.ListenAndServe()
 		}
-		if err != nil {
+		if err != nil && err != http.ErrServerClosed {
 			logger.Errorf("start api server failed: %v", err)
 		}
 	}()