middleware/proxy: sane(r) metrics

Add proxy_proto and re-instate proto to be the protocol of the incoming
query ("tcp" or "udp").

middleware/proxy/README.md

@@ -87,10 +87,10 @@ example.org.		1799	IN	SOA	sns.dns.icann.org. noc.dns.icann.org. 2016110711 7200
 
 If monitoring is enabled (via the *prometheus* directive) then the following metric is exported:
 
-* coredns_proxy_request_count_total{proto, from}
+* coredns_proxy_request_count_total{proto, proxy_proto, from}
 
-Where `proto` is the protocol used (`dns`, or `https_google`) and `from` is **FROM** specified in
-the config.
+Where `proxy_proto` is the protocol used (`dns`, or `https_google`) and `from` is **FROM** specified in
+the config, `proto` is the protocol used by the incoming query ("tcp" or "udp").
 
 ## Examples
 

middleware/proxy/metrics.go

@@ -16,7 +16,7 @@ var (
 		Name:      "request_duration_milliseconds",
 		Buckets:   append(prometheus.DefBuckets, []float64{50, 100, 200, 500, 1000, 2000, 3000, 4000, 5000, 10000}...),
 		Help:      "Histogram of the time (in milliseconds) each request took.",
-	}, []string{"proto", "from"})
+	}, []string{"proto", "proxy_proto", "from"})
 )
 
 // OnStartupMetrics sets up the metrics on startup. This is done for all proxy protocols.

middleware/proxy/proxy.go

@@ -93,7 +93,7 @@ func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 			host := upstream.Select()
 			if host == nil {
 
-				RequestDuration.WithLabelValues(upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
+				RequestDuration.WithLabelValues(state.Proto(), upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
 
 				return dns.RcodeServerFailure, errUnreachable
 			}
@@ -116,7 +116,7 @@ func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 			if backendErr == nil {
 				w.WriteMsg(reply)
 
-				RequestDuration.WithLabelValues(upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
+				RequestDuration.WithLabelValues(state.Proto(), upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
 
 				return 0, nil
 			}
@@ -131,7 +131,7 @@ func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 			}(host, timeout)
 		}
 
-		RequestDuration.WithLabelValues(upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
+		RequestDuration.WithLabelValues(state.Proto(), upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
 
 		return dns.RcodeServerFailure, errUnreachable
 	}