From 77fbb2c12b2c6a91992d259714e5d7c0c9d4356a Mon Sep 17 00:00:00 2001
From: Murali Reddy <muralimmreddy@gmail.com>
Date: Thu, 16 Apr 2020 13:13:52 +0530
Subject: [PATCH 1/2] introduce weavenpc_policy_enforcement_errors prometheus
 metric to track number of errors occured during enforcing network policies

Fixes #3791
---
 npc/metrics/metrics.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/npc/metrics/metrics.go b/npc/metrics/metrics.go
index 5c6149b8..cad65531 100644
--- a/npc/metrics/metrics.go
+++ b/npc/metrics/metrics.go
@@ -22,6 +22,12 @@ var (
 		},
 		[]string{"protocol", "dport"},
 	)
+	PolicyEnforcementErrors = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Name: "weavenpc_policy_enforcement_errors",
+			Help: "Errors occured in enforcing the network policies.",
+		},
+	)
 )
 
 func gatherMetrics() {
@@ -95,6 +101,9 @@ func Start(addr string) error {
 	if err := prometheus.Register(blockedConnections); err != nil {
 		return err
 	}
+	if err := prometheus.Register(PolicyEnforcementErrors); err != nil {
+		return err
+	}
 
 	http.Handle("/metrics", promhttp.Handler())
 

From 09a204b9786ca49342db0542a194972b055aa3a3 Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Fri, 22 May 2020 09:55:07 +0000
Subject: [PATCH 2/2] NPC: increment metric each time an error is logged

---
 prog/weave-npc/main.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/prog/weave-npc/main.go b/prog/weave-npc/main.go
index 9ac6f778..4da4a1de 100644
--- a/prog/weave-npc/main.go
+++ b/prog/weave-npc/main.go
@@ -34,7 +34,12 @@ var (
 	bridgePortName string
 )
 
-func handleError(err error) { common.CheckError(err) }
+func handleError(err error) {
+	if err != nil {
+		metrics.PolicyEnforcementErrors.Inc()
+		common.Log.Error(err)
+	}
+}
 
 func handleFatal(err error) { common.CheckFatal(err) }