Add prometheus support

metric/prometheus.go

@@ -0,0 +1,72 @@
+// Copyright 2020 astaxie
+//
+// 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 metric
+
+import (
+	"net/http"
+	"reflect"
+	"strconv"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/astaxie/beego"
+	"github.com/astaxie/beego/logs"
+)
+
+func PrometheusMiddleWare(next http.Handler) http.Handler {
+	summaryVec := prometheus.NewSummaryVec(prometheus.SummaryOpts{
+		Name:      beego.BConfig.AppName,
+		Subsystem: "http_request",
+		ConstLabels: map[string]string{
+			"server": beego.BConfig.ServerName,
+			"env":    beego.BConfig.RunMode,
+		},
+		Help: "The statics info for http request",
+	}, []string{"pattern", "method", "status"})
+
+	prometheus.MustRegister(summaryVec)
+
+	return http.HandlerFunc(func(writer http.ResponseWriter, q *http.Request) {
+		start := time.Now()
+		next.ServeHTTP(writer, q)
+		end := time.Now()
+		go report(end.Sub(start), writer, q, summaryVec)
+	})
+}
+
+func report(dur time.Duration, writer http.ResponseWriter, q *http.Request, vec *prometheus.SummaryVec) {
+	ctrl := beego.BeeApp.Handlers
+	ctx := ctrl.GetContext()
+	ctx.Reset(writer, q)
+	defer ctrl.GiveBackContext(ctx)
+
+	// We cannot read the status code from q.Response.StatusCode
+	// since the http server does not set q.Response. So q.Response is nil
+	// Thus, we use reflection to read the status from writer whose concrete type is http.response
+	responseVal := reflect.ValueOf(writer).Elem()
+	field := responseVal.FieldByName("status")
+	status := -1
+	if field.IsValid() && field.Kind() == reflect.Int {
+		status = int(field.Int())
+	}
+	ptn := "UNKNOWN"
+	if rt, found := ctrl.FindRouter(ctx); found {
+		ptn = rt.GetPattern()
+	} else {
+		logs.Warn("we can not find the router info for this request, so request will be recorded as UNKNOWN: " + q.URL.String())
+	}
+	vec.WithLabelValues(ptn, q.Method, strconv.Itoa(status)).Observe(float64(dur / time.Millisecond))
+}

metric/prometheus_test.go

@@ -0,0 +1,42 @@
+// Copyright 2020 astaxie
+//
+// 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 metric
+
+import (
+	"net/http"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/astaxie/beego/context"
+)
+
+func TestPrometheusMiddleWare(t *testing.T) {
+	middleware := PrometheusMiddleWare(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {}))
+	writer := &context.Response{}
+	request := &http.Request{
+		URL: &url.URL{
+			Host:    "localhost",
+			RawPath: "/a/b/c",
+		},
+		Method: "POST",
+	}
+	vec := prometheus.NewSummaryVec(prometheus.SummaryOpts{}, []string{"pattern", "method", "status"})
+
+	report(time.Second, writer, request, vec)
+	middleware.ServeHTTP(writer, request)
+}