add blobstore metric

Signed-off-by: Christian Richter <crichter@owncloud.com>

changelog/unreleased/add-s3ng-metrics.md

@@ -0,0 +1,5 @@
+Enhancement: Add s3ng metrics
+
+We have added rx/tx metrics to the s3ng blobstore driver.
+
+https://github.com/cs3org/reva/pull/3272

pkg/storage/fs/s3ng/blobstore/blobstore.go

@@ -30,6 +30,7 @@ import (
 	"github.com/minio/minio-go/v7"
 	"github.com/minio/minio-go/v7/pkg/credentials"
 	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 // Blobstore provides an interface to an s3 compatible blobstore
@@ -39,6 +40,18 @@ type Blobstore struct {
 	bucket string
 }
 
+type PrometheusAwareReader struct {
+	r io.Reader
+	m *prometheus.CounterVec
+}
+
+type PrometheusAwareReadCloser struct {
+	r io.ReadCloser
+	m *prometheus.CounterVec
+}
+
+var metrics = NewMetrics()
+
 // New returns a new Blobstore
 func New(endpoint, region, bucket, accessKey, secretKey string) (*Blobstore, error) {
 	u, err := url.Parse(endpoint)
@@ -62,8 +75,28 @@ func New(endpoint, region, bucket, accessKey, secretKey string) (*Blobstore, err
 	}, nil
 }
 
+func (p *PrometheusAwareReader) Read(b []byte) (n int, err error) {
+	n, err = p.r.Read(b)
+	p.m.WithLabelValues().Add(float64(n))
+	return
+}
+
+func (p *PrometheusAwareReadCloser) Read(b []byte) (n int, err error) {
+	n, err = p.r.Read(b)
+	p.m.WithLabelValues().Add(float64(n))
+	return
+}
+
+func (p *PrometheusAwareReadCloser) Close() error {
+	return p.r.Close()
+}
+
 // Upload stores some data in the blobstore under the given key
 func (bs *Blobstore) Upload(node *node.Node, reader io.Reader) error {
+	reader = &PrometheusAwareReader{
+		r: reader,
+		m: metrics.Tx,
+	}
 	size := int64(-1)
 	if file, ok := reader.(*os.File); ok {
 		info, err := file.Stat()
@@ -87,7 +120,10 @@ func (bs *Blobstore) Download(node *node.Node) (io.ReadCloser, error) {
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not download object '%s' from bucket '%s'", bs.path(node), bs.bucket)
 	}
-	return reader, nil
+	return &PrometheusAwareReadCloser{
+		r: reader,
+		m: metrics.Rx,
+	}, nil
 }
 
 // Delete deletes a blob from the blobstore

pkg/storage/fs/s3ng/blobstore/metrics.go

@@ -0,0 +1,39 @@
+package blobstore
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	// Namespace defines the namespace for the defines metrics.
+	Namespace = "ocis"
+
+	// Subsystem defines the subsystem for the defines metrics.
+	Subsystem = "thumbnails"
+)
+
+// Metrics defines the available metrics of this service.
+type Metrics struct {
+	Rx *prometheus.CounterVec
+	Tx *prometheus.CounterVec
+}
+
+// New initializes the available metrics.
+func NewMetrics() *Metrics {
+	m := &Metrics{
+		Rx: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Namespace: Namespace,
+			Subsystem: Subsystem,
+			Name:      "Rx",
+			Help:      "Storage access rx",
+		}, []string{}),
+		Tx: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Namespace: Namespace,
+			Subsystem: Subsystem,
+			Name:      "Tx",
+			Help:      "Storage access tx",
+		}, []string{}),
+	}
+	_ = prometheus.Register(m.Rx)
+	_ = prometheus.Register(m.Tx)
+
+	return m
+}