Skip redundant endpoints in "network inspect"

Signed-off-by: Dong Chen <dongluo.chen@docker.com>

api/handlers.go

@@ -271,8 +271,11 @@ func getNetworks(c *context, w http.ResponseWriter, r *http.Request) {
 func getNetwork(c *context, w http.ResponseWriter, r *http.Request) {
 	var id = mux.Vars(r)["networkid"]
 	if network := c.cluster.Networks().Uniq().Get(id); network != nil {
+		// there could be duplicate container endpoints in network, need to remove redundant
+		// see https://github.com/docker/swarm/issues/1969
+		cleanNetwork := network.RemoveDuplicateEndpoints()
 		w.Header().Set("Content-Type", "application/json")
-		json.NewEncoder(w).Encode(network)
+		json.NewEncoder(w).Encode(cleanNetwork)
 		return
 	}
 	httpError(w, fmt.Sprintf("No such network: %s", id), http.StatusNotFound)

cluster/network.go

@@ -78,6 +78,34 @@ func (networks Networks) Filter(names []string, ids []string, types []string) Ne
 	return out
 }
 
+// RemoveDuplicateEndpoints returns a copy of input network
+// where duplicate container endpoints in the network are removed.
+// See https://github.com/docker/swarm/issues/1969
+// This function should be disabled when the bug is fixed in Docker network
+func (network *Network) RemoveDuplicateEndpoints() *Network {
+	// build a map from endpointID -> endpointIndex
+	endpointMap := make(map[string]string)
+	// traverse the endpoints to find the correct endpointIndex for each endpointID
+	for endpointIndex, endpointResource := range network.NetworkResource.Containers {
+		endpointID := endpointResource.EndpointID
+		// if this endpointID doesn't exist yet, add it
+		// if this endpointID exists, but endpointIndex is not a duplicate, use
+		// this endpointIndex
+		if _, ok := endpointMap[endpointID]; !ok || !strings.HasPrefix(endpointIndex, "ep-") {
+			endpointMap[endpointID] = endpointIndex
+		}
+	}
+	// Make a copy of the network
+	netCopy := *network
+	// clean up existing endpoints
+	netCopy.Containers = make(map[string]dockerclient.EndpointResource)
+	// add the endpoint index from endpointMap
+	for _, index := range endpointMap {
+		netCopy.Containers[index] = network.Containers[index]
+	}
+	return &netCopy
+}
+
 // Get returns a network using its ID or Name
 func (networks Networks) Get(IDOrName string) *Network {
 	// Abort immediately if the name is empty.

cluster/network_test.go

@@ -80,3 +80,112 @@ func TestNetworkUniq(t *testing.T) {
 	local3 := networks.Uniq().Get("local3")
 	assert.Nil(t, local3)
 }
+
+func TestRemoveDuplicateEndpoints(t *testing.T) {
+	engine1 := &Engine{ID: "id1"}
+	network := Network{
+		dockerclient.NetworkResource{
+			ID:   "global",
+			Name: "voteappbase_voteapp",
+			Containers: map[string]dockerclient.EndpointResource{
+				"028771f7f6a54c486d441ecfc92aad68e0836a1f0a5a0c227c514f14848e2b54": {
+					Name:        "voteappbase_worker_1",
+					EndpointID:  "49f621862a0659f462870a6cd15874da44592e399f41da2a3019d81b7427315b",
+					MacAddress:  "02:42:0a:00:02:04",
+					IPv4Address: "10.0.2.4/24",
+					IPv6Address: "",
+				},
+				"6baa9c82be8fe731556b371312989e22fb9e67121698c94b4890dd554381d97b": {
+					Name:        "voteappbase_voting-app_1",
+					EndpointID:  "95e831e91a76c87a51b93217645fcaf093c209e2b6691493bfdc0cf2c39698d0",
+					MacAddress:  "02:42:0a:00:02:05",
+					IPv4Address: "10.0.2.5/24",
+					IPv6Address: "",
+				},
+				"995eccf14e33797b15c2c1ba67f68b7ced0754c42f096e02cc1c488a418f6126": {
+					Name:        "db",
+					EndpointID:  "e881cf9ba6dcc5495630d4e2ffba9178f7f4456f12938624562e2cf79888e6b4",
+					MacAddress:  "02:42:0a:00:02:02",
+					IPv4Address: "10.0.2.2/24",
+					IPv6Address: "",
+				},
+				"e4547f30d8dcd93a9c0da8b44e2a8f793eb01260aa478243605d137a90688611": {
+					Name:        "voteappbase_result-app_1",
+					EndpointID:  "d79ed2653731eccc968bd32da158bf74646511242d7a96f31fd350eda5b658cb",
+					MacAddress:  "02:42:0a:00:02:06",
+					IPv4Address: "10.0.2.6/24",
+					IPv6Address: "",
+				},
+				"ep-49f621862a0659f462870a6cd15874da44592e399f41da2a3019d81b7427315b": {
+					Name:        "voteappbase_worker_1",
+					EndpointID:  "49f621862a0659f462870a6cd15874da44592e399f41da2a3019d81b7427315b",
+					MacAddress:  "02:42:0a:00:02:04",
+					IPv4Address: "10.0.2.4/24",
+					IPv6Address: "",
+				},
+				"ep-95e831e91a76c87a51b93217645fcaf093c209e2b6691493bfdc0cf2c39698d0": {
+					Name:        "voteappbase_voting-app_1",
+					EndpointID:  "95e831e91a76c87a51b93217645fcaf093c209e2b6691493bfdc0cf2c39698d0",
+					MacAddress:  "02:42:0a:00:02:05",
+					IPv4Address: "10.0.2.5/24",
+					IPv6Address: "",
+				},
+				"ep-d79ed2653731eccc968bd32da158bf74646511242d7a96f31fd350eda5b658cb": {
+					Name:        "voteappbase_result-app_1",
+					EndpointID:  "d79ed2653731eccc968bd32da158bf74646511242d7a96f31fd350eda5b658cb",
+					MacAddress:  "02:42:0a:00:02:06",
+					IPv4Address: "10.0.2.6/24",
+					IPv6Address: "",
+				},
+				"ep-e881cf9ba6dcc5495630d4e2ffba9178f7f4456f12938624562e2cf79888e6b4": {
+					Name:        "db",
+					EndpointID:  "e881cf9ba6dcc5495630d4e2ffba9178f7f4456f12938624562e2cf79888e6b4",
+					MacAddress:  "02:42:0a:00:02:02",
+					IPv4Address: "10.0.2.2/24",
+					IPv6Address: "",
+				},
+				"ep-eaa1cf9ba6dcc5495630d4e2ffba917af7f4456f1293a624562e2cf79aaae6b4": {
+					Name:        "db-stale",
+					EndpointID:  "eaa1cf9ba6dcc5495630d4e2ffba917af7f4456f1293a624562e2cf79aaae6b4",
+					MacAddress:  "02:42:0a:00:02:32",
+					IPv4Address: "10.0.2.33/24",
+					IPv6Address: "",
+				},
+				"ep-f2e8540123a5b5894da462b8fd06de6394cb1a263392167b87e1b7195ec33055": {
+					Name:        "redis",
+					EndpointID:  "f2e8540123a5b5894da462b8fd06de6394cb1a263392167b87e1b7195ec33055",
+					MacAddress:  "02:42:0a:00:02:03",
+					IPv4Address: "10.0.2.3/24",
+					IPv6Address: "",
+				},
+				"f7e42305c1c50b145814d28508312e7374edbafebd8f04115606e58fde96f441": {
+					Name:        "redis",
+					EndpointID:  "f2e8540123a5b5894da462b8fd06de6394cb1a263392167b87e1b7195ec33055",
+					MacAddress:  "02:42:0a:00:02:03",
+					IPv4Address: "10.0.2.3/24",
+					IPv6Address: "",
+				},
+			},
+		}, engine1}
+
+	cleanNet := network.RemoveDuplicateEndpoints()
+	assert.Equal(t, len(cleanNet.Containers), 6)
+
+	// good endpoints are preserved
+	resource, ok := cleanNet.Containers["028771f7f6a54c486d441ecfc92aad68e0836a1f0a5a0c227c514f14848e2b54"]
+	assert.True(t, ok)
+	assert.Equal(t, resource.EndpointID, "49f621862a0659f462870a6cd15874da44592e399f41da2a3019d81b7427315b")
+
+	resource, ok = cleanNet.Containers["f7e42305c1c50b145814d28508312e7374edbafebd8f04115606e58fde96f441"]
+	assert.True(t, ok)
+	assert.Equal(t, resource.EndpointID, "f2e8540123a5b5894da462b8fd06de6394cb1a263392167b87e1b7195ec33055")
+
+	// duplicate endpoint should be removed
+	resource, ok = cleanNet.Containers["ep-f2e8540123a5b5894da462b8fd06de6394cb1a263392167b87e1b7195ec33055"]
+	assert.False(t, ok)
+
+	// stale endpoint is preserved
+	resource, ok = cleanNet.Containers["ep-eaa1cf9ba6dcc5495630d4e2ffba917af7f4456f1293a624562e2cf79aaae6b4"]
+	assert.True(t, ok)
+	assert.Equal(t, resource.EndpointID, "eaa1cf9ba6dcc5495630d4e2ffba917af7f4456f1293a624562e2cf79aaae6b4")
+}