Add swagger (OpenAPI 2.0) support (#1245)

* Add swagger (OpenAPI 2.0) support
* Gererate swagger_doc before building bundle image

pkg/controller/openapi.go

@@ -0,0 +1,78 @@
+/*
+Copyright 2019 The Fission Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controller
+
+import (
+	"net/http"
+
+	"github.com/emicklei/go-restful"
+	restfulspec "github.com/emicklei/go-restful-openapi"
+	"github.com/go-openapi/spec"
+)
+
+var specTag []spec.Tag
+
+func openAPI() http.Handler {
+	restful.DefaultContainer.Add(openAPIWebService())
+
+	config := restfulspec.Config{
+		WebServices:                   restful.RegisteredWebServices(),
+		APIPath:                       "/v2/apidocs.json",
+		PostBuildSwaggerObjectHandler: enrichSwaggerObject}
+
+	restful.DefaultContainer.Add(restfulspec.NewOpenAPIService(config))
+
+	return restful.DefaultContainer
+}
+
+func openAPIWebService() *restful.WebService {
+	ws := new(restful.WebService)
+
+	// CRD resource
+	RegisterEnvironmentRoute(ws)
+	RegisterFunctionRoute(ws)
+	RegisterHTTPTriggerRoute(ws)
+	RegisterMessageQueueTriggerRoute(ws)
+	RegisterPackageRoute(ws)
+	RegisterWatchRoute(ws)
+	RegisterTimeTriggerRoute(ws)
+	RegisterCanaryConfigRoute(ws)
+
+	// proxy
+	RegisterStorageServiceProxyRoute(ws)
+
+	return ws
+}
+
+func enrichSwaggerObject(swo *spec.Swagger) {
+	swo.Info = &spec.Info{
+		InfoProps: spec.InfoProps{
+			Title:       "Fission OpenAPI 2.0",
+			Description: openapiDescription,
+			Version:     "v1",
+		},
+	}
+	swo.Tags = specTag
+}
+
+var openapiDescription = `
+OpenAPI 2.0 document for fission controller
+* Metadata (v1.ObjectMeta) should be empty when creating a CRD resource. Kubernetes will assign it automatically.
+* Following semantic errors are known issues and won't affect the API accessibility.
+  - Operations must have unique operationIds.
+  - All scale semantic errors. (Due to go-restful exposes inner fields of k8s struct).
+`