Merge pull request #272 from prameshj/nodecache-followup

Follow up changes to node-cache PR

Dockerfile.node-cache

@@ -13,11 +13,10 @@
 # limitations under the License.
 
 FROM debian:stable-slim
-
-MAINTAINER Pavithra Ramesh <[email protected]>
-
-RUN apt-get update
-RUN apt-get -y install iproute2 iptables
+RUN apt-get update && apt-get install -y \
+    iproute2 \
+    iptables \
+&& rm -rf /var/lib/apt/lists/*
 ADD bin/ARG_ARCH/ARG_BIN /ARG_BIN
 EXPOSE 53 53/udp
 EXPOSE 53 53/tcp

cmd/node-cache/Corefile

@@ -3,6 +3,7 @@
         cache 30
         reload
         loop
+        log
         bind 1.2.3.4
         forward . 8.8.8.8 {
                 force_tcp

cmd/node-cache/main.go

@@ -173,48 +173,46 @@ func (c *cacheApp) parseAndValidateFlags() error {
 	return nil
 }
 
-func (c *cacheApp) Run() {
+func (c *cacheApp) run() {
 	c.params.exitChan = make(chan bool, 1)
-	go func(ch chan bool) {
-		tick := time.NewTicker(c.params.interval * time.Second)
-		for {
-			select {
-			case <-tick.C:
-				for _, rule := range c.iptablesRules {
-					exists, err := c.iptables.EnsureRule(utiliptables.Prepend, rule.table, rule.chain, rule.args...)
-					if !exists {
-						if err != nil {
-							cache.teardownNetworking()
-							clog.Fatalf("Failed to add back non-existent rule %v", rule)
-						}
-						clog.Infof("Added back nonexistent rule - %v", rule)
-					}
-					if err != nil {
-						clog.Errorf("Failed to check rule %v - %s", rule, err)
-					}
-				}
-
-				exists, err := c.netifHandle.EnsureDummyDevice(c.params.intfName)
+	tick := time.NewTicker(c.params.interval * time.Second)
+	for {
+		select {
+		case <-tick.C:
+			for _, rule := range c.iptablesRules {
+				exists, err := c.iptables.EnsureRule(utiliptables.Prepend, rule.table, rule.chain, rule.args...)
 				if !exists {
 					if err != nil {
 						cache.teardownNetworking()
-						clog.Fatalf("Failed to add back non-existent interface %s", c.params.intfName)
+						clog.Fatalf("Failed to add back non-existent rule %v", rule)
 					}
-					clog.Infof("Added back nonexistent interface - %s", c.params.intfName)
+					clog.Infof("Added back nonexistent rule - %v", rule)
 				}
 				if err != nil {
-					clog.Errorf("Failed to check dummy device %s - %s", c.params.intfName, err)
+					clog.Errorf("Failed to check rule %v - %s", rule, err)
 				}
-			case <-ch:
-				clog.Warningf("Exiting iptables check goroutine")
-				return
 			}
+
+			exists, err := c.netifHandle.EnsureDummyDevice(c.params.intfName)
+			if !exists {
+				if err != nil {
+					cache.teardownNetworking()
+					clog.Fatalf("Failed to add back non-existent interface %s", c.params.intfName)
+				}
+				clog.Infof("Added back nonexistent interface - %s", c.params.intfName)
+			}
+			if err != nil {
+				clog.Errorf("Failed to check dummy device %s - %s", c.params.intfName, err)
+			}
+		case <-c.params.exitChan:
+			clog.Warningf("Exiting iptables check goroutine")
+			return
 		}
-	}(c.params.exitChan)
+	}
 }
 
 func main() {
-	cache.Run()
+	go cache.run()
 	coremain.Run()
 	// Unlikely to reach here, if we did it is because coremain exited and the signal was not trapped.
 	clog.Errorf("Untrapped signal, tearing down")