use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/mholt/caddy/caddyhttp/expvar/expvar.go

@@ -0,0 +1,59 @@
+// Copyright 2015 Light Code Labs, LLC
+//
+// 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 expvar
+
+import (
+	"expvar"
+	"fmt"
+	"net/http"
+
+	"github.com/mholt/caddy/caddyhttp/httpserver"
+)
+
+// ExpVar is a simple struct to hold expvar's configuration
+type ExpVar struct {
+	Next     httpserver.Handler
+	Resource Resource
+}
+
+// ServeHTTP handles requests to expvar's configured entry point with
+// expvar, or passes all other requests up the chain.
+func (e ExpVar) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
+	if httpserver.Path(r.URL.Path).Matches(string(e.Resource)) {
+		expvarHandler(w, r)
+		return 0, nil
+	}
+	return e.Next.ServeHTTP(w, r)
+}
+
+// expvarHandler returns a JSON object will all the published variables.
+//
+// This is lifted straight from the expvar package.
+func expvarHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	fmt.Fprintf(w, "{\n")
+	first := true
+	expvar.Do(func(kv expvar.KeyValue) {
+		if !first {
+			fmt.Fprintf(w, ",\n")
+		}
+		first = false
+		fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
+	})
+	fmt.Fprintf(w, "\n}\n")
+}
+
+// Resource contains the path to the expvar entry point
+type Resource string