Cleanup collection of prometheus metrics

controllers/nginx/pkg/metric/collector/nginx.go

@@ -0,0 +1,130 @@
+/*
+Copyright 2017 The Kubernetes 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 collector
+
+import (
+	"github.com/golang/glog"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	activeDesc = prometheus.NewDesc(
+		"nginx_active_connections",
+		"total number of active connections",
+		nil, nil)
+
+	acceptedDesc = prometheus.NewDesc(
+		"nginx_accepted_connections",
+		"total number of accepted client connections",
+		nil, nil)
+
+	handledDesc = prometheus.NewDesc(
+		"nginx_handled_connections",
+		"total number of handled connections",
+		nil, nil)
+
+	requestsDesc = prometheus.NewDesc(
+		"nginx_total_requests",
+		"total number of client requests",
+		nil, nil)
+
+	readingDesc = prometheus.NewDesc(
+		"nginx_current_reading_connections",
+		"current number of connections where nginx is reading the request header",
+		nil, nil)
+
+	writingDesc = prometheus.NewDesc(
+		"nginx_current_writing_connections",
+		"current number of connections where nginx is writing the response back to the client",
+		nil, nil)
+
+	waitingDesc = prometheus.NewDesc(
+		"nginx_current_waiting_connections",
+		"current number of idle client connections waiting for a request",
+		nil, nil)
+)
+
+type (
+	nginxStatusCollector struct {
+		scrapeChan chan scrapeRequest
+	}
+)
+
+func NewNginxStatus() (prometheus.Collector, error) {
+	p := nginxStatusCollector{
+		scrapeChan: make(chan scrapeRequest),
+	}
+
+	go p.start()
+
+	return p, nil
+}
+
+// Describe implements prometheus.Collector.
+func (p nginxStatusCollector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- activeDesc
+	ch <- acceptedDesc
+	ch <- handledDesc
+	ch <- requestsDesc
+	ch <- readingDesc
+	ch <- writingDesc
+	ch <- waitingDesc
+}
+
+// Collect implements prometheus.Collector.
+func (p nginxStatusCollector) Collect(ch chan<- prometheus.Metric) {
+	req := scrapeRequest{results: ch, done: make(chan struct{})}
+	p.scrapeChan <- req
+	<-req.done
+}
+
+func (p nginxStatusCollector) start() {
+	for req := range p.scrapeChan {
+		ch := req.results
+		p.scrape(ch)
+		req.done <- struct{}{}
+	}
+}
+
+func (p nginxStatusCollector) Stop() {
+	close(p.scrapeChan)
+}
+
+// nginxStatusCollector scrap the nginx status
+func (p nginxStatusCollector) scrape(ch chan<- prometheus.Metric) {
+	s, err := getNginxStatus()
+	if err != nil {
+		glog.Warningf("unexpected error obtaining nginx status info: %v", err)
+		return
+	}
+
+	ch <- prometheus.MustNewConstMetric(activeDesc,
+		prometheus.GaugeValue, float64(s.Active))
+	ch <- prometheus.MustNewConstMetric(acceptedDesc,
+		prometheus.GaugeValue, float64(s.Accepted))
+	ch <- prometheus.MustNewConstMetric(handledDesc,
+		prometheus.GaugeValue, float64(s.Handled))
+	ch <- prometheus.MustNewConstMetric(requestsDesc,
+		prometheus.GaugeValue, float64(s.Requests))
+	ch <- prometheus.MustNewConstMetric(readingDesc,
+		prometheus.GaugeValue, float64(s.Reading))
+	ch <- prometheus.MustNewConstMetric(writingDesc,
+		prometheus.GaugeValue, float64(s.Writing))
+	ch <- prometheus.MustNewConstMetric(waitingDesc,
+		prometheus.GaugeValue, float64(s.Waiting))
+
+}