weave connect should be best-effort, and return errors for any fails

router/connection_maker.go

@@ -48,7 +48,8 @@ func (cm *ConnectionMaker) Start() {
 	go cm.queryLoop(actionChan)
 }
 
-func (cm *ConnectionMaker) InitiateConnections(peers []string) error {
+func (cm *ConnectionMaker) InitiateConnections(peers []string) []error {
+	errors := []error{}
 	addrs := make(map[string]*net.TCPAddr)
 	for _, peer := range peers {
 		host, port, err := net.SplitHostPort(peer)
@@ -56,11 +57,11 @@ func (cm *ConnectionMaker) InitiateConnections(peers []string) error {
 			host = peer
 			port = "0" // we use that as an indication that "no port was supplied"
 		}
-		addr, err := net.ResolveTCPAddr("tcp4", fmt.Sprintf("%s:%s", host, port))
-		if err != nil {
-			return err
+		if addr, err := net.ResolveTCPAddr("tcp4", fmt.Sprintf("%s:%s", host, port)); err != nil {
+			errors = append(errors, err)
+		} else {
+			addrs[peer] = addr
 		}
-		addrs[peer] = addr
 	}
 	cm.actionChan <- func() bool {
 		for peer, addr := range addrs {
@@ -72,7 +73,7 @@ func (cm *ConnectionMaker) InitiateConnections(peers []string) error {
 		}
 		return true
 	}
-	return nil
+	return errors
 }
 
 func (cm *ConnectionMaker) ForgetConnections(peers []string) {

weaver/main.go

@@ -144,8 +144,8 @@ func main() {
 	}
 
 	router.Start()
-	if err := router.ConnectionMaker.InitiateConnections(peers); err != nil {
-		log.Fatal(err)
+	if errors := router.ConnectionMaker.InitiateConnections(peers); len(errors) > 0 {
+		log.Fatal(errorMessages(errors))
 	}
 
 	// The weave script always waits for a status call to succeed,
@@ -158,6 +158,14 @@ func main() {
 	SignalHandlerLoop(router)
 }
 
+func errorMessages(errors []error) string {
+	var result []string
+	for _, err := range errors {
+		result = append(result, err.Error())
+	}
+	return strings.Join(result, "\n")
+}
+
 func options() map[string]string {
 	options := make(map[string]string)
 	flag.Visit(func(f *flag.Flag) {
@@ -248,8 +256,8 @@ func handleHTTP(router *weave.Router, httpAddr string, allocator *ipam.Allocator
 		if err := r.ParseForm(); err != nil {
 			http.Error(w, fmt.Sprint("unable to parse form: ", err), http.StatusBadRequest)
 		}
-		if err := router.ConnectionMaker.InitiateConnections(r.Form["peer"]); err != nil {
-			http.Error(w, fmt.Sprint("invalid peer address: ", err), http.StatusBadRequest)
+		if errors := router.ConnectionMaker.InitiateConnections(r.Form["peer"]); len(errors) > 0 {
+			http.Error(w, errorMessages(errors), http.StatusBadRequest)
 		}
 	})