upgrade prometheus client-go

Signed-off-by: zackzhangkai <zackzhang@yunify.com>

vendor/github.com/prometheus-community/prom-label-proxy/injectproxy/routes.go

@@ -0,0 +1,156 @@
+// Copyright 2020 The Prometheus 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 injectproxy
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+
+	"github.com/prometheus/prometheus/pkg/labels"
+	"github.com/prometheus/prometheus/promql/parser"
+)
+
+type routes struct {
+	upstream  *url.URL
+	handler   http.Handler
+	label     string
+	mux       *http.ServeMux
+	modifiers map[string]func(*http.Response) error
+}
+
+func NewRoutes(upstream *url.URL, label string) *routes {
+	proxy := httputil.NewSingleHostReverseProxy(upstream)
+
+	r := &routes{
+		upstream: upstream,
+		handler:  proxy,
+		label:    label,
+	}
+	mux := http.NewServeMux()
+	mux.Handle("/federate", enforceMethods(r.federate, "GET"))
+	mux.Handle("/api/v1/query", enforceMethods(r.query, "GET", "POST"))
+	mux.Handle("/api/v1/query_range", enforceMethods(r.query, "GET", "POST"))
+	mux.Handle("/api/v1/alerts", enforceMethods(r.noop, "GET"))
+	mux.Handle("/api/v1/rules", enforceMethods(r.noop, "GET"))
+	mux.Handle("/api/v2/silences", enforceMethods(r.silences, "GET", "POST"))
+	mux.Handle("/api/v2/silences/", enforceMethods(r.silences, "GET", "POST"))
+	mux.Handle("/api/v2/silence/", enforceMethods(r.deleteSilence, "DELETE"))
+	r.mux = mux
+	r.modifiers = map[string]func(*http.Response) error{
+		"/api/v1/rules":  modifyAPIResponse(r.filterRules),
+		"/api/v1/alerts": modifyAPIResponse(r.filterAlerts),
+	}
+	proxy.ModifyResponse = r.ModifyResponse
+	return r
+}
+
+func (r *routes) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	lvalue := req.URL.Query().Get(r.label)
+	if lvalue == "" {
+		http.Error(w, fmt.Sprintf("Bad request. The %q query parameter must be provided.", r.label), http.StatusBadRequest)
+		return
+	}
+	req = req.WithContext(withLabelValue(req.Context(), lvalue))
+	// Remove the proxy label from the query parameters.
+	q := req.URL.Query()
+	q.Del(r.label)
+	req.URL.RawQuery = q.Encode()
+
+	r.mux.ServeHTTP(w, req)
+}
+
+func (r *routes) ModifyResponse(resp *http.Response) error {
+	m, found := r.modifiers[resp.Request.URL.Path]
+	if !found {
+		// Return the server's response unmodified.
+		return nil
+	}
+	return m(resp)
+}
+
+func enforceMethods(h http.HandlerFunc, methods ...string) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		for _, m := range methods {
+			if m == req.Method {
+				h(w, req)
+				return
+			}
+		}
+		http.NotFound(w, req)
+	})
+}
+
+type ctxKey int
+
+const keyLabel ctxKey = iota
+
+func mustLabelValue(ctx context.Context) string {
+	label, ok := ctx.Value(keyLabel).(string)
+	if !ok {
+		panic(fmt.Sprintf("can't find the %q value in the context", keyLabel))
+	}
+	if label == "" {
+		panic(fmt.Sprintf("empty %q value in the context", keyLabel))
+	}
+	return label
+}
+
+func withLabelValue(ctx context.Context, label string) context.Context {
+	return context.WithValue(ctx, keyLabel, label)
+}
+
+func (r *routes) noop(w http.ResponseWriter, req *http.Request) {
+	r.handler.ServeHTTP(w, req)
+}
+
+func (r *routes) query(w http.ResponseWriter, req *http.Request) {
+	expr, err := parser.ParseExpr(req.FormValue("query"))
+	if err != nil {
+		return
+	}
+
+	e := NewEnforcer([]*labels.Matcher{
+		{
+			Name:  r.label,
+			Type:  labels.MatchEqual,
+			Value: mustLabelValue(req.Context()),
+		},
+	}...)
+	if err := e.EnforceNode(expr); err != nil {
+		return
+	}
+
+	q := req.URL.Query()
+	q.Set("query", expr.String())
+	req.URL.RawQuery = q.Encode()
+
+	r.handler.ServeHTTP(w, req)
+}
+
+func (r *routes) federate(w http.ResponseWriter, req *http.Request) {
+	matcher := &labels.Matcher{
+		Name:  r.label,
+		Type:  labels.MatchEqual,
+		Value: mustLabelValue(req.Context()),
+	}
+
+	q := req.URL.Query()
+	q.Set("match[]", "{"+matcher.String()+"}")
+	req.URL.RawQuery = q.Encode()
+
+	r.handler.ServeHTTP(w, req)
+}