Export MeteredRoundTripper

Exports the  struct so that it can be asserted
and adds a  method that is called by the zip VFS.

5 files changed, 29 insertions, 27 deletions

diff --git a/internal/httptransport/metered_round_tripper.go b/internal/httptransport/metered_round_tripper.go
index fc652086..e8facbaa 100644
--- a/internal/httptransport/metered_round_tripper.go
+++ b/internal/httptransport/metered_round_tripper.go
@@ -12,7 +12,9 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-type meteredRoundTripper struct {
+// MeteredRoundTripper is a custom http.Transport that implements the http.RoundTripper interface.
+// It holds prometheus metrics to report connection usage and durations.
+type MeteredRoundTripper struct {
 	next        http.RoundTripper
 	name        string
 	tracer      *prometheus.HistogramVec
@@ -29,7 +31,7 @@ func NewMeteredRoundTripper(transport *http.Transport, name string, tracerVec, d
 		transport = DefaultTransport
 	}
 
-	return &meteredRoundTripper{
+	return &MeteredRoundTripper{
 		next:        transport,
 		name:        name,
 		tracer:      tracerVec,
@@ -39,9 +41,9 @@ func NewMeteredRoundTripper(transport *http.Transport, name string, tracerVec, d
 	}
 }
 
-// RoundTripper wraps the original http.Transport into a meteredRoundTripper which
+// RoundTrip wraps the original http.Transport into a MeteredRoundTripper which
 // reports metrics on request duration, tracing and request count
-func (mrt *meteredRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
+func (mrt *MeteredRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
 	start := time.Now()
 
 	ctx := httptrace.WithClientTrace(r.Context(), mrt.newTracer(start))
@@ -67,7 +69,7 @@ func (mrt *meteredRoundTripper) RoundTrip(r *http.Request) (*http.Response, erro
 	return resp, nil
 }
 
-func (mrt *meteredRoundTripper) logResponse(req *http.Request, resp *http.Response) {
+func (mrt *MeteredRoundTripper) logResponse(req *http.Request, resp *http.Response) {
 	if log.GetLevel() == log.TraceLevel {
 		l := log.WithFields(log.Fields{
 			"client_name":     mrt.name,
@@ -82,3 +84,8 @@ func (mrt *meteredRoundTripper) logResponse(req *http.Request, resp *http.Respon
 		l.Traceln("response")
 	}
 }
+
+// RegisterProtocol calls the RegisterProtocol on the MeteredRoundTripper's next Transport
+func (mrt *MeteredRoundTripper) RegisterProtocol(scheme string, rt http.RoundTripper) {
+	mrt.next.(*http.Transport).RegisterProtocol(scheme, rt)
+}
diff --git a/internal/httptransport/trace.go b/internal/httptransport/trace.go
index 9ece5fc4..f99b282d 100644
--- a/internal/httptransport/trace.go
+++ b/internal/httptransport/trace.go
@@ -8,7 +8,7 @@ import (
 	"gitlab.com/gitlab-org/labkit/log"
 )
 
-func (mrt *meteredRoundTripper) newTracer(start time.Time) *httptrace.
+func (mrt *MeteredRoundTripper) newTracer(start time.Time) *httptrace.
 	ClientTrace {
 	trace := &httptrace.ClientTrace{
 		GetConn: func(host string) {
@@ -71,7 +71,7 @@ func (mrt *meteredRoundTripper) newTracer(start time.Time) *httptrace.
 	return trace
 }
 
-func (mrt *meteredRoundTripper) httpTraceObserve(label string, start time.Time) {
+func (mrt *MeteredRoundTripper) httpTraceObserve(label string, start time.Time) {
 	mrt.tracer.WithLabelValues(label).
 		Observe(time.Since(start).Seconds())
 }
diff --git a/internal/httptransport/transport.go b/internal/httptransport/transport.go
index fcadc5fe..a462f7ee 100644
--- a/internal/httptransport/transport.go
+++ b/internal/httptransport/transport.go
@@ -12,7 +12,7 @@ import (
 )
 
 const (
-	// DefaultTTFBTimeout is the timeout used in the meteredRoundTripper
+	// DefaultTTFBTimeout is the timeout used in the MeteredRoundTripper
 	// when calling http.Transport.RoundTrip. The request will be cancelled
 	// if the response takes longer than this.
 	DefaultTTFBTimeout = 15 * time.Second
diff --git a/internal/httptransport/transport_test.go b/internal/httptransport/transport_test.go
index feaf63b6..25c27f17 100644
--- a/internal/httptransport/transport_test.go
+++ b/internal/httptransport/transport_test.go
@@ -55,7 +55,7 @@ func Test_withRoundTripper(t *testing.T) {
 				timeout: time.Nanosecond,
 			}
 
-			mtr := &meteredRoundTripper{next: next, durations: histVec, counter: counterVec, ttfbTimeout: DefaultTTFBTimeout}
+			mtr := &MeteredRoundTripper{next: next, durations: histVec, counter: counterVec, ttfbTimeout: DefaultTTFBTimeout}
 			r := httptest.NewRequest("GET", "/", nil)
 
 			res, err := mtr.RoundTrip(r)
@@ -86,7 +86,7 @@ func TestRoundTripTTFBTimeout(t *testing.T) {
 		err:     nil,
 	}
 
-	mtr := &meteredRoundTripper{next: next, durations: histVec, counter: counterVec, ttfbTimeout: time.Nanosecond}
+	mtr := &MeteredRoundTripper{next: next, durations: histVec, counter: counterVec, ttfbTimeout: time.Nanosecond}
 	req, err := http.NewRequest("GET", "https://gitlab.com", nil)
 	require.NoError(t, err)
 
diff --git a/internal/vfs/zip/vfs.go b/internal/vfs/zip/vfs.go
index b7055b01..29847ac9 100644
--- a/internal/vfs/zip/vfs.go
+++ b/internal/vfs/zip/vfs.go
@@ -8,13 +8,12 @@ import (
 	"sync"
 	"time"
 
-	"gitlab.com/gitlab-org/gitlab-pages/internal/httpfs"
-	"gitlab.com/gitlab-org/gitlab-pages/internal/httptransport"
-
 	"github.com/patrickmn/go-cache"
 
 	"gitlab.com/gitlab-org/gitlab-pages/internal/config"
+	"gitlab.com/gitlab-org/gitlab-pages/internal/httpfs"
 	"gitlab.com/gitlab-org/gitlab-pages/internal/httprange"
+	"gitlab.com/gitlab-org/gitlab-pages/internal/httptransport"
 	"gitlab.com/gitlab-org/gitlab-pages/internal/vfs"
 	"gitlab.com/gitlab-org/gitlab-pages/metrics"
 )
@@ -63,6 +62,14 @@ func New(cfg *config.ZipServing) vfs.VFS {
 			// TODO: make this timeout configurable
 			// https://gitlab.com/gitlab-org/gitlab-pages/-/issues/457
 			Timeout: 30 * time.Minute,
+			Transport: httptransport.NewMeteredRoundTripper(
+				httptransport.NewTransport(),
+				"zip_vfs",
+				metrics.HTTPRangeTraceDuration,
+				metrics.HTTPRangeRequestDuration,
+				metrics.HTTPRangeRequestsTotal,
+				httptransport.DefaultTTFBTimeout,
+			),
 		},
 	}
 
@@ -96,25 +103,13 @@ func (fs *zipVFS) Reconfigure(cfg *config.Config) error {
 }
 
 func (fs *zipVFS) reconfigureTransport(cfg *config.Config) error {
-	transport := httptransport.NewTransport()
-
 	fsTransport, err := httpfs.NewFileSystemPath(cfg.Zip.AllowedPaths)
 	if err != nil {
 		return err
 	}
 
-	transport.RegisterProtocol("file", http.NewFileTransport(fsTransport))
-
-	mrt := httptransport.NewMeteredRoundTripper(
-		transport,
-		"httprange_client",
-		metrics.HTTPRangeTraceDuration,
-		metrics.HTTPRangeRequestDuration,
-		metrics.HTTPRangeRequestsTotal,
-		httptransport.DefaultTTFBTimeout,
-	)
-
-	fs.httpClient.Transport = mrt
+	fs.httpClient.Transport.(*httptransport.MeteredRoundTripper).
+		RegisterProtocol("file", http.NewFileTransport(fsTransport))
 
 	return nil
 }