leave idle networks so that they can be deleted

Author: codekitchen

Dockerfile

@@ -7,7 +7,7 @@ RUN apt-get update \
  && apt-get clean \
  && rm -r /var/lib/apt/lists/*
 
-RUN wget https://github.com/codekitchen/dinghy-http-proxy/releases/download/join-networks-v1/join-networks.tar.gz \
+RUN wget https://github.com/codekitchen/dinghy-http-proxy/releases/download/join-networks-v2/join-networks.tar.gz \
  && tar -C /app -xzvf join-networks.tar.gz \
  && rm join-networks.tar.gz
 

build.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 set -e
 
-docker run --rm -v "$PWD":/go/src/github.com/codekitchen/dinghy-http-proxy -w /go/src/github.com/codekitchen/dinghy-http-proxy golang:1.6 go build -v -o join-networks
+docker run --rm -v "$PWD":/go/src/github.com/codekitchen/dinghy-http-proxy -w /go/src/github.com/codekitchen/dinghy-http-proxy golang:1.8 go build -v -o join-networks
 tar czvf join-networks.tar.gz join-networks
 rm join-networks

join-networks.go

@@ -20,16 +20,26 @@ func main() {
 	}
 
 	currentNetworks := getJoinedNetworks(client, *containerName)
-	bridgeNetworks := getBridgeNetworks(client)
+	bridgeNetworks := getActiveBridgeNetworks(client)
 
-	for _, id := range bridgeNetworks {
-		if !currentNetworks[id] {
-			err := client.ConnectNetwork(id, docker.NetworkConnectionOptions{
-				Container: *containerName,
-			})
-			if err != nil {
-				panic(err)
-			}
+	toJoin := getNetworksToJoin(currentNetworks, bridgeNetworks)
+	toLeave := getNetworksToLeave(currentNetworks, bridgeNetworks)
+
+	for _, id := range toLeave {
+		err := client.DisconnectNetwork(id, docker.NetworkConnectionOptions{
+			Container: *containerName,
+		})
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	for _, id := range toJoin {
+		err := client.ConnectNetwork(id, docker.NetworkConnectionOptions{
+			Container: *containerName,
+		})
+		if err != nil {
+			panic(err)
 		}
 	}
 }
@@ -49,16 +59,39 @@ func getJoinedNetworks(client *docker.Client, containerName string) (networks ma
 	return
 }
 
-func getBridgeNetworks(client *docker.Client) (ids []string) {
-	networks, err := client.ListNetworks()
+func getActiveBridgeNetworks(client *docker.Client) (networks map[string]bool) {
+	networks = make(map[string]bool)
+
+	allNetworks, err := client.ListNetworks()
 	if err != nil {
 		panic(err)
 	}
 
-	for _, net := range networks {
-		if net.Driver == "bridge" {
-			ids = append(ids, net.ID)
+	for _, net := range allNetworks {
+		if net.Driver == "bridge" && len(net.Containers) > 0 {
+			networks[net.ID] = true
 		}
 	}
+
+	return
+}
+
+func getNetworksToJoin(currentNetworks map[string]bool, bridgeNetworks map[string]bool) (ids []string) {
+	for id := range bridgeNetworks {
+		if !currentNetworks[id] {
+			ids = append(ids, id)
+		}
+	}
+
+	return
+}
+
+func getNetworksToLeave(currentNetworks map[string]bool, bridgeNetworks map[string]bool) (ids []string) {
+	for id := range currentNetworks {
+		if !bridgeNetworks[id] {
+			ids = append(ids, id)
+		}
+	}
+
 	return
 }