[NPM] support network policy controller and its unit tests (#849)

* first version of network policy controller and its unit tests

* update reconcile and deleteNetworkPolicy function to correctly install and uninstall default Azure NPM chain.

* To explicitly manage default Azure NPM chain in deleteNetworkPolicy function

* correct comments and delete unused variable

* fix missed returing errors in codes

* Correct to check DeletionTimestamp and DeletionGracePeriodSeconds variables

* removed placeholder functions in network policy controoler and added more test cases (e.g., update and adding multiple network policies)

* - applied comments (use explict names, locating lock in a better place)

* add two methods to save and restore iptables in unit test

* comment out unused function

* early filter in updateNetworkPolicy function if they are the same network policies. Update unit tests to test more network policies events

* - start using klog package instead of log package

* remove unneeded defer for lock

* Locate of adding and deleting network policy object from our network policy cache in a right place. Correct prometheus metric code.

* use cached network policy key instead of network policy object as method parameter in cleanUpNetworkPolicy

* remove redundant check

* Remove ns- prefix as key in RawNpMap. Update UT to check prometheus metrics. Applied better naming and removed redundancy codes.

* minor update for varialbe names

* remove dependency between UT by re-initializing metrics. Correct message.

Author: JungukCho

go.mod

@@ -39,6 +39,7 @@ require (
 	k8s.io/api v0.18.2
 	k8s.io/apimachinery v0.18.2
 	k8s.io/client-go v0.18.2
+	k8s.io/klog v1.0.0
 	sigs.k8s.io/controller-runtime v0.6.0
 	software.sslmate.com/src/go-pkcs12 v0.0.0-20201102150903-66718f75db0e // indirect
 )

npm/metrics/prometheus_metrics.go

@@ -61,6 +61,11 @@ var nodeLevelRegistry = prometheus.NewRegistry()
 var clusterLevelRegistry = prometheus.NewRegistry()
 var haveInitialized = false
 
+func ReInitializeAllMetrics() {
+	haveInitialized = false
+	InitializeAll()
+}
+
 // InitializeAll creates all the Prometheus Metrics. The metrics will be nil before this method is called.
 func InitializeAll() {
 	if !haveInitialized {