Add metrics for httprange and trace logs

Add metrics and trace logs

Enables meteredRoundTripper to log response data in a Traceln() call.
It adds a name to the round tripper for easy logging.
Adds two new metrics to be used by the `httprange` package to track
number of requests made to object storage.

Apply 1 suggestion(s) to 1 file(s)

(cherry picked from commit 57a98108c728ba6e6575a95899455d5fac536ae1)

4 files changed, 47 insertions, 8 deletions

diff --git a/internal/httprange/http_reader.go b/internal/httprange/http_reader.go
index 72ca3cf9..9b6a8bbd 100644
--- a/internal/httprange/http_reader.go
+++ b/internal/httprange/http_reader.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"gitlab.com/gitlab-org/gitlab-pages/internal/httptransport"
+	"gitlab.com/gitlab-org/gitlab-pages/metrics"
 )
 
 var (
@@ -44,10 +45,12 @@ type Reader struct {
 //  instead https://gitlab.com/gitlab-org/gitlab-pages/-/issues/457
 var httpClient = &http.Client{
 	// The longest time the request can be executed
-	Timeout:   30 * time.Minute,
-	Transport: httptransport.InternalTransport,
-	// TODO: add metrics https://gitlab.com/gitlab-org/gitlab-pages/-/issues/448
-	// Transport: httptransport.NewTransportWithMetrics(metrics.ZIPHttpReaderReqDuration, metrics.ZIPHttpReaderReqTotal),
+	Timeout: 30 * time.Minute,
+	Transport: httptransport.NewTransportWithMetrics(
+		metrics.ZipFileServingReqDuration,
+		metrics.ZipFileServingReqTotal,
+		httptransport.WithMeteredRoundTripperName("httprange_client"),
+	),
 }
 
 // ensureResponse is set before reading from it.
diff --git a/internal/httptransport/transport.go b/internal/httptransport/transport.go
index e6094ed7..4f177914 100644
--- a/internal/httptransport/transport.go
+++ b/internal/httptransport/transport.go
@@ -6,6 +6,7 @@ import (
 	"net"
 	"net/http"
 	"strconv"
+	"strings"
 	"sync"
 	"time"
 
@@ -25,10 +26,14 @@ var (
 
 type meteredRoundTripper struct {
 	next      http.RoundTripper
+	name      string
 	durations *prometheus.GaugeVec
 	counter   *prometheus.CounterVec
 }
 
+// Option setting for metered round tripper
+type Option func(*meteredRoundTripper)
+
 func newInternalTransport() *http.Transport {
 	return &http.Transport{
 		DialTLS: func(network, addr string) (net.Conn, error) {
@@ -44,12 +49,25 @@ func newInternalTransport() *http.Transport {
 
 // NewTransportWithMetrics will create a custom http.RoundTripper that can be used with an http.Client.
 // The RoundTripper will report metrics based on the collectors passed.
-func NewTransportWithMetrics(gaugeVec *prometheus.GaugeVec, counterVec *prometheus.CounterVec) http.RoundTripper {
-	return &meteredRoundTripper{
+func NewTransportWithMetrics(gaugeVec *prometheus.GaugeVec, counterVec *prometheus.CounterVec, options ...Option) http.RoundTripper {
+	mtr := &meteredRoundTripper{
 		next:      InternalTransport,
 		durations: gaugeVec,
 		counter:   counterVec,
 	}
+
+	for _, option := range options {
+		option(mtr)
+	}
+
+	return mtr
+}
+
+// WithMeteredRoundTripperName adds a name to the meteredRoundTripper instance
+func WithMeteredRoundTripperName(name string) func(*meteredRoundTripper) {
+	return func(tripper *meteredRoundTripper) {
+		tripper.name = name
+	}
 }
 
 // This is here because macOS does not support the SSL_CERT_FILE and
@@ -87,9 +105,27 @@ func (mrt *meteredRoundTripper) RoundTrip(r *http.Request) (*http.Response, erro
 		return nil, err
 	}
 
+	mrt.logResponse(r, resp)
+
 	statusCode := strconv.Itoa(resp.StatusCode)
 	mrt.durations.WithLabelValues(statusCode).Set(time.Since(start).Seconds())
 	mrt.counter.WithLabelValues(statusCode).Inc()
 
 	return resp, nil
 }
+
+func (mrt *meteredRoundTripper) logResponse(req *http.Request, resp *http.Response) {
+	if log.GetLevel() == log.TraceLevel {
+		l := log.WithFields(log.Fields{
+			"client_name":     mrt.name,
+			"req_url":         req.URL.String(),
+			"res_status_code": resp.StatusCode,
+		})
+
+		for header, value := range resp.Header {
+			l = l.WithField(strings.ToLower(header), strings.Join(value, ";"))
+		}
+
+		l.Traceln("response")
+	}
+}
diff --git a/internal/httptransport/transport_test.go b/internal/httptransport/transport_test.go
index 330d1022..60fbbb47 100644
--- a/internal/httptransport/transport_test.go
+++ b/internal/httptransport/transport_test.go
@@ -58,7 +58,7 @@ func Test_withRoundTripper(t *testing.T) {
 				err: tt.err,
 			}
 
-			mtr := &meteredRoundTripper{next, gaugeVec, counterVec}
+			mtr := &meteredRoundTripper{next: next, durations: gaugeVec, counter: counterVec}
 			r := httptest.NewRequest("GET", "/", nil)
 
 			res, err := mtr.RoundTrip(r)
diff --git a/internal/logging/logging.go b/internal/logging/logging.go
index 4ba86985..3432cdf7 100644
--- a/internal/logging/logging.go
+++ b/internal/logging/logging.go
@@ -18,7 +18,7 @@ func ConfigureLogging(format string, verbose bool) error {
 	}
 
 	if verbose {
-		levelOption = log.WithLogLevel("debug")
+		levelOption = log.WithLogLevel("trace")
 	} else {
 		levelOption = log.WithLogLevel("info")
 	}