initial commit

collector/stats.go

@@ -0,0 +1,105 @@
+package collector
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type statsResponse struct {
+	StatusCode int    `json:"status_code"`
+	StatusText string `json:"status_text"`
+	Data       stats  `json:"data"`
+}
+
+type stats struct {
+	Version   string   `json:"version"`
+	Health    string   `json:"health"`
+	StartTime int64    `json:"start_time"`
+	Topics    []*topic `json:"topics"`
+}
+
+type statsCollector struct {
+	nsqUrl string
+
+	topicCount   prometheus.Gauge
+	channelCount *prometheus.GaugeVec
+	clientCount  *prometheus.GaugeVec
+
+	topics   topicCollector
+	channels channelCollector
+	clients  clientCollector
+}
+
+// NewStatsCollector create a collector which collects all NSQ metrics
+// from the /stats route of the NSQ host.
+func NewStatsCollector(nsqUrl string) Collector {
+	const namespace = "nsq"
+	return &statsCollector{
+		nsqUrl: nsqUrl,
+
+		topicCount: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      "topics_total",
+			Help:      "The total number of topics",
+		}),
+		channelCount: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      "channels_total",
+			Help:      "The total number of channels",
+		}, []string{"topic"}),
+		clientCount: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Name:      "channels_total",
+			Help:      "The total number of channels",
+		}, []string{"topic", "channel"}),
+
+		topics:   newTopicCollector(namespace),
+		channels: newChannelCollector(namespace),
+		clients:  newClientCollector(namespace),
+	}
+}
+
+func (c *statsCollector) Collect(out chan<- prometheus.Metric) error {
+	s, err := c.fetchStats()
+	if err != nil {
+		return err
+	}
+
+	c.topicCount.Set(float64(len(s.Topics)))
+
+	for _, topic := range s.Topics {
+		c.channelCount.With(prometheus.Labels{
+			"topic": topic.Name,
+		}).Set(float64(len(topic.Channels)))
+
+		c.topics.update(topic, out)
+		for _, channel := range topic.Channels {
+			c.clientCount.With(prometheus.Labels{
+				"topic":   topic.Name,
+				"channel": channel.Name,
+			}).Set(float64(len(channel.Clients)))
+
+			c.channels.update(topic.Name, channel, out)
+			for _, client := range channel.Clients {
+				c.clients.update(topic.Name, channel.Name, client, out)
+			}
+		}
+	}
+	return nil
+}
+
+func (c *statsCollector) fetchStats() (*stats, error) {
+	resp, err := http.Get(c.nsqUrl)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var s statsResponse
+	if err = json.NewDecoder(resp.Body).Decode(&s); err != nil {
+		return nil, err
+	}
+	return &s.Data, nil
+}