httptransport: add a request_id to logs

This re-uses any trace ID that OpenTelemetry supports, or generates a
weakly random one based on some request features.

Closes: quay#1547
Signed-off-by: Hank Donnay <hdonnay@redhat.com>

httptransport/common.go

@@ -1,14 +1,22 @@
 package httptransport
 
 import (
+	"encoding/hex"
 	"errors"
 	"fmt"
+	"hash"
+	"hash/fnv"
+	"io"
 	"mime"
 	"net/http"
 	"path"
 	"sort"
 	"strconv"
 	"strings"
+	"sync"
+
+	"github.com/quay/zlog"
+	"go.opentelemetry.io/otel/trace"
 
 	"github.com/quay/claircore"
 )
@@ -106,3 +114,26 @@ func (a *accept) Match(mt string) bool {
 	t, s := mt[:i], mt[i+1:]
 	return a.Type == t && (a.Subtype == s || a.Subtype == "*")
 }
+
+var idPool sync.Pool
+
+func withRequestID(r *http.Request) *http.Request {
+	const key = `request_id`
+	ctx := r.Context()
+	sctx := trace.SpanContextFromContext(ctx)
+	if sctx.HasTraceID() {
+		ctx = zlog.ContextWithValues(ctx, key, sctx.TraceID().String())
+	} else {
+		h := idPool.Get().(hash.Hash64)
+		if h == nil {
+			h = fnv.New64a()
+		} else {
+			h.Reset()
+		}
+		io.WriteString(h, r.RequestURI)
+		io.WriteString(h, r.RemoteAddr)
+		ctx = zlog.ContextWithValues(ctx, key, hex.EncodeToString(h.Sum(nil)))
+		idPool.Put(h)
+	}
+	return r.WithContext(ctx)
+}

httptransport/indexer_v1.go

@@ -68,7 +68,7 @@ func (h *IndexerV1) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			Dur("duration", time.Since(start)).
 			Msg("handled HTTP request")
 	}()
-	h.inner.ServeHTTP(wr, r)
+	h.inner.ServeHTTP(wr, withRequestID(r))
 }
 
 func (h *IndexerV1) indexReport(w http.ResponseWriter, r *http.Request) {

httptransport/matcher_v1.go

@@ -76,7 +76,7 @@ func (h *MatcherV1) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			Dur("duration", time.Since(start)).
 			Msg("handled HTTP request")
 	}()
-	h.inner.ServeHTTP(wr, r)
+	h.inner.ServeHTTP(wr, withRequestID(r))
 }
 
 func (h *MatcherV1) vulnerabilityReport(w http.ResponseWriter, r *http.Request) {

httptransport/notification_v1.go

@@ -68,7 +68,7 @@ func (h *NotificationV1) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			Dur("duration", time.Since(start)).
 			Msg("handled HTTP request")
 	}()
-	h.inner.ServeHTTP(wr, r)
+	h.inner.ServeHTTP(wr, withRequestID(r))
 }
 
 func (h *NotificationV1) serveHTTP(w http.ResponseWriter, r *http.Request) {