Added support for sharing the same listener between CNM net and IPAM plugins

Author: ofiliz

cnm/ipam/ipam.go

@@ -71,6 +71,7 @@ func (plugin *ipamPlugin) Start(config *common.PluginConfig) error {
 
 	// Add protocol handlers.
 	listener := plugin.Listener
+	listener.AddEndpoint(plugin.EndpointType)
 	listener.AddHandler(getCapabilitiesPath, plugin.getCapabilities)
 	listener.AddHandler(getAddressSpacesPath, plugin.getDefaultAddressSpaces)
 	listener.AddHandler(requestPoolPath, plugin.requestPool)

cnm/network/network.go

@@ -76,6 +76,7 @@ func (plugin *netPlugin) Start(config *common.PluginConfig) error {
 
 	// Add protocol handlers.
 	listener := plugin.Listener
+	listener.AddEndpoint(plugin.EndpointType)
 	listener.AddHandler(getCapabilitiesPath, plugin.getCapabilities)
 	listener.AddHandler(createNetworkPath, plugin.createNetwork)
 	listener.AddHandler(deleteNetworkPath, plugin.deleteNetwork)

cnm/plugin.go

@@ -38,28 +38,36 @@ func (plugin *Plugin) Initialize(config *common.PluginConfig) error {
 	// Initialize the base plugin.
 	plugin.Plugin.Initialize(config)
 
-	// Create the plugin path.
-	os.MkdirAll(pluginPath, 0660)
-
-	// Create the listener.
-	var localAddr string
-	if plugin.Name != "test" {
-		localAddr = path.Join(pluginPath, config.Name+plugin.Name)
+	if config.Listener == nil {
+		// Create the plugin path.
+		os.MkdirAll(pluginPath, 0660)
+
+		// Create the listener.
+		var localAddr string
+		if plugin.Name != "test" {
+			localAddr = path.Join(pluginPath, config.Name+plugin.Name)
+		}
+
+		listener, err := common.NewListener("unix", localAddr)
+		if err != nil {
+			return err
+		}
+
+		// Add generic protocol handlers.
+		listener.AddHandler(activatePath, plugin.activate)
+
+		// Start the listener.
+		err = listener.Start(config.ErrChan)
+		if err != nil {
+			return err
+		}
+
+		config.Listener = listener
 	}
 
-	listener, err := common.NewListener("unix", localAddr)
-	if err != nil {
-		return err
-	}
-
-	// Add generic protocol handlers.
-	listener.AddHandler(activatePath, plugin.activate)
-
-	// Start the listener.
-	err = listener.Start(config.ErrChan)
-	plugin.Listener = listener
+	plugin.Listener = config.Listener
 
-	return err
+	return nil
 }
 
 // Uninitializes the plugin.
@@ -78,7 +86,7 @@ func (plugin *Plugin) activate(w http.ResponseWriter, r *http.Request) {
 
 	log.Request(plugin.Name, &req, nil)
 
-	resp := activateResponse{[]string{plugin.EndpointType}}
+	resp := activateResponse{Implements: plugin.Listener.GetEndpoints()}
 	err := plugin.Listener.Encode(w, &resp)
 
 	log.Response(plugin.Name, &resp, err)

common/listener.go

@@ -13,15 +13,17 @@ import (
 	"github.com/Azure/azure-container-networking/log"
 )
 
-// Listener object
+// Listener represents an HTTP listener.
 type Listener struct {
 	protocol     string
 	localAddress string
+	endpoints    []string
+	active       bool
 	l            net.Listener
 	mux          *http.ServeMux
 }
 
-// Creates a new Listener.
+// NewListener creates a new Listener.
 func NewListener(protocol string, localAddress string) (*Listener, error) {
 	listener := Listener{
 		protocol:     protocol,
@@ -59,16 +61,17 @@ func (listener *Listener) Start(errChan chan error) error {
 		errChan <- http.Serve(listener.l, listener.mux)
 	}()
 
+	listener.active = true
 	return nil
 }
 
-// Stops listening for requests from libnetwork.
+// Stop stops listening for requests.
 func (listener *Listener) Stop() {
-
-	// Succeed early if no socket was requested.
-	if listener.localAddress == "" {
+	// Ignore if not active.
+	if !listener.active {
 		return
 	}
+	listener.active = false
 
 	// Stop servicing requests.
 	listener.l.Close()
@@ -81,17 +84,27 @@ func (listener *Listener) Stop() {
 	log.Printf("[Listener] Stopped listening on %s", listener.localAddress)
 }
 
-// Returns the HTTP mux for the listener.
+// GetMux returns the HTTP mux for the listener.
 func (listener *Listener) GetMux() *http.ServeMux {
 	return listener.mux
 }
 
-// Registers a protocol handler.
+// GetEndpoints returns the list of registered protocol endpoints.
+func (listener *Listener) GetEndpoints() []string {
+	return listener.endpoints
+}
+
+// AddEndpoint registers a protocol endpoint.
+func (listener *Listener) AddEndpoint(endpoint string) {
+	listener.endpoints = append(listener.endpoints, endpoint)
+}
+
+// AddHandler registers a protocol handler.
 func (listener *Listener) AddHandler(path string, handler func(http.ResponseWriter, *http.Request)) {
 	listener.mux.HandleFunc(path, handler)
 }
 
-// Decodes JSON payload.
+// Decode receives and decodes JSON payload to a request.
 func (listener *Listener) Decode(w http.ResponseWriter, r *http.Request, request interface{}) error {
 	var err error
 
@@ -108,7 +121,7 @@ func (listener *Listener) Decode(w http.ResponseWriter, r *http.Request, request
 	return err
 }
 
-// Encodes JSON payload.
+// Encode encodes and sends a response as JSON payload.
 func (listener *Listener) Encode(w http.ResponseWriter, response interface{}) error {
 	err := json.NewEncoder(w).Encode(response)
 	if err != nil {
@@ -117,8 +130,3 @@ func (listener *Listener) Encode(w http.ResponseWriter, response interface{}) er
 	}
 	return err
 }
-
-// Sends an error response.
-func (listener *Listener) SendError(w http.ResponseWriter, errMessage string) {
-	json.NewEncoder(w).Encode(map[string]string{"Err": errMessage})
-}

common/plugin.go

@@ -26,12 +26,13 @@ type PluginApi interface {
 
 // Plugin common configuration.
 type PluginConfig struct {
-	Name    string
-	Version string
-	NetApi  interface{}
-	IpamApi interface{}
-	ErrChan chan error
-	Store   store.KeyValueStore
+	Name     string
+	Version  string
+	NetApi   interface{}
+	IpamApi  interface{}
+	Listener *Listener
+	ErrChan  chan error
+	Store    store.KeyValueStore
 }
 
 // NewPlugin creates a new Plugin object.