Count accepted gRPC connections

3 files changed, 45 insertions, 3 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1952e25d9..3431b0705 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@ UNRELEASED
   https://gitlab.com/gitlab-org/gitaly/merge_requests/148
 - Hide chatty logs behind GITALY_DEBUG=1. Log access times.
   https://gitlab.com/gitlab-org/gitaly/merge_requests/149
+- Count accepted gRPC connections
+  https://gitlab.com/gitlab-org/gitaly/merge_requests/151
 
 v0.10.0
 
diff --git a/cmd/gitaly/main.go b/cmd/gitaly/main.go
index 082e67696..24bfbd8cc 100644
--- a/cmd/gitaly/main.go
+++ b/cmd/gitaly/main.go
@@ -8,6 +8,7 @@ import (
 	"os"
 
 	"gitlab.com/gitlab-org/gitaly/internal/config"
+	"gitlab.com/gitlab-org/gitaly/internal/connectioncounter"
 	"gitlab.com/gitlab-org/gitaly/internal/service"
 	"gitlab.com/gitlab-org/gitaly/internal/service/middleware/loghandler"
 	"gitlab.com/gitlab-org/gitaly/internal/service/middleware/panichandler"
@@ -77,7 +78,7 @@ func main() {
 			log.Fatalf("configure tcp listener: %v", err)
 		}
 		log.Printf("listening at tcp address %q", addr)
-		listeners = append(listeners, l)
+		listeners = append(listeners, connectioncounter.New("tcp", l))
 	}
 
 	server := grpc.NewServer(
@@ -124,6 +125,6 @@ func createUnixListener(socketPath string) (net.Listener, error) {
 	if err := os.Remove(socketPath); err != nil && !os.IsNotExist(err) {
 		return nil, err
 	}
-
-	return net.Listen("unix", socketPath)
+	l, err := net.Listen("unix", socketPath)
+	return connectioncounter.New("unix", l), err
 }
diff --git a/internal/connectioncounter/connectioncounter.go b/internal/connectioncounter/connectioncounter.go
new file mode 100644
index 000000000..21e28cf1b
--- /dev/null
+++ b/internal/connectioncounter/connectioncounter.go
@@ -0,0 +1,39 @@
+package connectioncounter
+
+import (
+	"net"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	connTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gitaly_connections_total",
+			Help: "Total number of connections accepted by this Gitaly process",
+		},
+		[]string{"type"},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(connTotal)
+}
+
+func New(cType string, l net.Listener) net.Listener {
+	return &countingListener{
+		cType:    cType,
+		Listener: l,
+	}
+}
+
+type countingListener struct {
+	net.Listener
+	cType string
+}
+
+func (cl *countingListener) Accept() (net.Conn, error) {
+	conn, err := cl.Listener.Accept()
+	connTotal.WithLabelValues(cl.cType).Inc()
+	return conn, err
+}