From 9a4e42ba8b2d56c47be8a5857f87728d71d7b29d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Busse?= <bj.rn@baerlin.eu>
Date: Thu, 8 Mar 2018 02:40:26 +0000
Subject: [PATCH] Add a prometheus exporter and some metrics

---
 daemon.go | 21 ++++++++++++++++++---
 goircd.go | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/daemon.go b/daemon.go
index 4b29257..97e9854 100644
--- a/daemon.go
+++ b/daemon.go
@@ -28,6 +28,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 const (
@@ -60,15 +62,20 @@ func GetRoom(name string) (r *Room, found bool) {
 	return r, found
 }
 
-func SendLusers(client *Client) {
-	lusers := 0
+func GetNumberOfRegisteredUsers(client *Client) (nusers float64){
+	nusers = 0
 	clientsM.RLock()
 	for client := range clients {
 		if client.registered {
-			lusers++
+			nusers++
 		}
 	}
 	clientsM.RUnlock()
+	return nusers
+}
+
+func SendLusers(client *Client) {
+	lusers := GetNumberOfRegisteredUsers(client)
 	client.ReplyNicknamed("251", fmt.Sprintf("There are %d users and 0 invisible on 1 servers", lusers))
 }
 
@@ -268,6 +275,8 @@ func ClientRegister(client *Client, cmd string, cols []string) {
 			}
 		}
 		client.registered = true
+		clients_irc_total.Inc()
+		clients_connected.Set(GetNumberOfRegisteredUsers(client))
 		client.ReplyNicknamed("001", "Hi, welcome to IRC")
 		client.ReplyNicknamed("002", "Your host is "+*hostname+", running goircd "+version)
 		client.ReplyNicknamed("003", "This server was created sometime")
@@ -338,17 +347,22 @@ func HandlerJoin(client *Client, cmd string) {
 	Denied:
 		client.ReplyNicknamed("475", room, "Cannot join channel (+k) - bad key")
 	Joined:
+		clients_irc_rooms_total.With(prometheus.Labels{"room":"all"}).Inc()
+		clients_irc_rooms_total.With(prometheus.Labels{"room":room}).Inc()
 	}
 }
 
 func Processor(events chan ClientEvent, finished chan struct{}) {
 	var now time.Time
+
 	go func() {
 		for {
 			time.Sleep(10 * time.Second)
 			events <- ClientEvent{eventType: EventTick}
 		}
 	}()
+
+
 	for event := range events {
 		now = time.Now()
 		client := event.client
@@ -618,6 +632,7 @@ func Processor(events chan ClientEvent, finished chan struct{}) {
 			default:
 				client.ReplyNicknamed("421", cmd, "Unknown command")
 			}
+			clients_connected.Set(GetNumberOfRegisteredUsers(client))
 		}
 	}
 }
diff --git a/goircd.go b/goircd.go
index fa32bb1..d827d0c 100644
--- a/goircd.go
+++ b/goircd.go
@@ -24,12 +24,15 @@ import (
 	"io/ioutil"
 	"log"
 	"net"
+	"net/http"
 	"path"
 	"path/filepath"
 	"strings"
 	"time"
 
 	proxyproto "github.com/Freeaqingme/go-proxyproto"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 const (
@@ -47,7 +50,37 @@ var (
 	tlsBind      = flag.String("tlsbind", "", "TLS address to bind to")
 	tlsPEM       = flag.String("tlspem", "", "Path to TLS certificat+key PEM file")
 	proxyTimeout = flag.Uint("proxytimeout", PROXY_TIMEOUT, "Timeout when using proxy protocol")
+	metrics      = flag.Bool("metrics", false, "Enable metrics export")
 	verbose      = flag.Bool("v", false, "Enable verbose logging.")
+
+	clients_tls_total = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name: "clients_tls_connected_total",
+			Help: "Number of connected clients during the lifetime of the server.",
+		},
+	)
+
+	clients_irc_total = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name: "clients_irc_connected_total",
+			Help: "Number of connected irc clients during the lifetime of the server.",
+		},
+	)
+
+	clients_irc_rooms_total = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "clients_irc_rooms_connected_total",
+			Help: "Number of clients joined to rooms during the lifetime of the server.",
+		},
+		[]string{"room"},
+	)
+
+	clients_connected = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "clients_connected",
+			Help: "Number of connected clients.",
+		},
+	)
 )
 
 func listenerLoop(sock net.Listener, events chan ClientEvent) {
@@ -58,6 +91,7 @@ func listenerLoop(sock net.Listener, events chan ClientEvent) {
 			continue
 		}
 		client := NewClient(conn)
+		clients_tls_total.Inc()
 		go client.Processor(events)
 	}
 }
@@ -149,9 +183,25 @@ func Run() {
 
 		go listenerLoop(listenerTLS, events)
 	}
+
+	// Create endpoint for prometheus metrics export
+	if *metrics {
+		go prom_export()
+	}
+
 	Processor(events, make(chan struct{}))
 }
 
+func prom_export() {
+	prometheus.MustRegister(clients_tls_total)
+	prometheus.MustRegister(clients_irc_total)
+	prometheus.MustRegister(clients_irc_rooms_total)
+	prometheus.MustRegister(clients_connected)
+
+	http.Handle("/metrics", promhttp.Handler())
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}
+
 func main() {
 	flag.Parse()
 	Run()