Count streamio method calls

1 files changed, 23 insertions, 0 deletions

diff --git a/streamio/stream.go b/streamio/stream.go
index 379556afe..3e90f0e42 100644
--- a/streamio/stream.go
+++ b/streamio/stream.go
@@ -8,9 +8,22 @@ import (
 	"io"
 	"os"
 	"strconv"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	methodCount = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gitaly_streamio_method_calls_total",
+			Help: "Usage counters of gitaly streamio methods",
+		}, []string{"method"},
+	)
 )
 
 func init() {
+	prometheus.MustRegister(methodCount)
+
 	bufSize64, err := strconv.ParseInt(os.Getenv("GITALY_STREAMIO_WRITE_BUFFER_SIZE"), 10, 32)
 	if err == nil && bufSize64 > 0 {
 		WriteBufferSize = int(bufSize64)
@@ -30,7 +43,11 @@ type receiveReader struct {
 	err      error
 }
 
+func countMethod(method string) { methodCount.WithLabelValues(method).Inc() }
+
 func (rr *receiveReader) Read(p []byte) (int, error) {
+	countMethod("reader.Read")
+
 	if len(rr.data) == 0 {
 		rr.data, rr.err = rr.receiver()
 	}
@@ -44,6 +61,8 @@ func (rr *receiveReader) Read(p []byte) (int, error) {
 
 // WriteTo implements io.WriterTo.
 func (rr *receiveReader) WriteTo(w io.Writer) (int64, error) {
+	countMethod("reader.WriteTo")
+
 	var written int64
 
 	// Deal with left-over state in rr.data and rr.err, if any
@@ -93,6 +112,8 @@ type sendWriter struct {
 }
 
 func (sw *sendWriter) Write(p []byte) (int, error) {
+	countMethod("writer.Write")
+
 	var sent int
 
 	for len(p) > 0 {
@@ -114,6 +135,8 @@ func (sw *sendWriter) Write(p []byte) (int, error) {
 
 // ReadFrom implements io.ReaderFrom.
 func (sw *sendWriter) ReadFrom(r io.Reader) (int64, error) {
+	countMethod("writer.ReadFrom")
+
 	var nRead int64
 	buf := make([]byte, WriteBufferSize)