[usage] Report upload/download metrics for usage report

components/usage/pkg/contentservice/client.go

@@ -11,6 +11,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"time"
 
 	"github.com/gitpod-io/gitpod/common-go/log"
 	"github.com/gitpod-io/gitpod/content-service/api"
@@ -29,7 +30,12 @@ func New(service api.UsageReportServiceClient) *Client {
 	return &Client{service: service}
 }
 
-func (c *Client) UploadUsageReport(ctx context.Context, filename string, report UsageReport) error {
+func (c *Client) UploadUsageReport(ctx context.Context, filename string, report UsageReport) (err error) {
+	start := time.Now()
+	defer func() {
+		observeReportUploadDuration(time.Since(start), err)
+	}()
+
 	uploadURLResp, err := c.service.UploadURL(ctx, &api.UsageReportUploadURLRequest{Name: filename})
 	if err != nil {
 		return fmt.Errorf("failed to get upload URL from usage report service: %w", err)
@@ -67,7 +73,12 @@ func (c *Client) UploadUsageReport(ctx context.Context, filename string, report
 	return nil
 }
 
-func (c *Client) DownloadUsageReport(ctx context.Context, filename string) (UsageReport, error) {
+func (c *Client) DownloadUsageReport(ctx context.Context, filename string) (report UsageReport, err error) {
+	start := time.Now()
+	defer func() {
+		observeReportDownloadDuration(time.Since(start), err)
+	}()
+
 	downloadURlResp, err := c.service.DownloadURL(ctx, &api.UsageReportDownloadURLRequest{
 		Name: filename,
 	})
@@ -104,7 +115,6 @@ func (c *Client) DownloadUsageReport(ctx context.Context, filename string) (Usag
 	defer decompressor.Close()
 
 	decoder := json.NewDecoder(decompressor)
-	var report UsageReport
 	if err := decoder.Decode(&report); err != nil {
 		return UsageReport{}, fmt.Errorf("failed to deserialize report: %w", err)
 	}

components/usage/pkg/contentservice/metrics.go

@@ -0,0 +1,63 @@
+// Copyright (c) 2022 Gitpod GmbH. All rights reserved.
+// Licensed under the GNU Affero General Public License (AGPL).
+// See License-AGPL.txt in the project root for license information.
+
+package contentservice
+
+import (
+	"fmt"
+	"github.com/prometheus/client_golang/prometheus"
+	"time"
+)
+
+const (
+	namespace = "gitpod"
+	subsystem = "usage"
+)
+
+var (
+	reportUploadDurationSeconds = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: namespace,
+		Subsystem: subsystem,
+		Name:      "report_upload_duration_seconds",
+		Help:      "Histogram of time it takes (in seconds) to upload a usage report to content service",
+	}, []string{"outcome"})
+
+	reportDownloadDurationSeconds = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: namespace,
+		Subsystem: subsystem,
+		Name:      "report_download_duration_seconds",
+		Help:      "Histogram of time it takes (in seconds) to download usage report from content service",
+	}, []string{"outcome"})
+)
+
+func RegisterMetrics(reg *prometheus.Registry) error {
+	metrics := []prometheus.Collector{
+		reportUploadDurationSeconds,
+		reportDownloadDurationSeconds,
+	}
+	for _, metric := range metrics {
+		err := reg.Register(metric)
+		if err != nil {
+			return fmt.Errorf("failed to register metric: %w", err)
+		}
+	}
+
+	return nil
+}
+
+func observeReportUploadDuration(d time.Duration, err error) {
+	outcome := "ok"
+	if err != nil {
+		outcome = "error"
+	}
+	reportUploadDurationSeconds.WithLabelValues(outcome).Observe(d.Seconds())
+}
+
+func observeReportDownloadDuration(d time.Duration, err error) {
+	outcome := "ok"
+	if err != nil {
+		outcome = "error"
+	}
+	reportDownloadDurationSeconds.WithLabelValues(outcome).Observe(d.Seconds())
+}

components/usage/pkg/server/server.go

@@ -130,6 +130,10 @@ func Start(cfg Config) error {
 		log.Info("No controller schedule specified, controller will be disabled.")
 	}
 
+	err = contentservice.RegisterMetrics(srv.MetricsRegistry())
+	if err != nil {
+		return fmt.Errorf("failed to register content service metrics: %w", err)
+	}
 	var contentService contentservice.Interface = &contentservice.NoOpClient{}
 	if cfg.ContentServiceAddress != "" {
 		contentServiceConn, err := grpc.Dial(cfg.ContentServiceAddress, grpc.WithTransportCredentials(insecure.NewCredentials()))