introduce 'weave connect' to connect a running router to other peers

Getting this to work with 'wget' is just too cumbersome especially
when it comes to getting the error message out. So 'curl' only.

weave

@@ -3,13 +3,14 @@ set -e
 
 usage() {
     echo "Usage:"
-    echo "weave launch <cidr> [-password <password>] <peer> ..."
-    echo "weave run    <cidr> <docker run args> ..."
-    echo "weave start  <cidr> <container_id>"
-    echo "weave attach <cidr> <container_id>"
-    echo "weave detach <cidr> <container_id>"
-    echo "weave expose <cidr>"
-    echo "weave hide   <cidr>"
+    echo "weave launch  <cidr> [-password <password>] <peer> ..."
+    echo "weave run     <cidr> <docker run args> ..."
+    echo "weave start   <cidr> <container_id>"
+    echo "weave attach  <cidr> <container_id>"
+    echo "weave detach  <cidr> <container_id>"
+    echo "weave expose  <cidr>"
+    echo "weave hide    <cidr>"
+    echo "weave connect <peer>"
     echo "weave status"
     echo "weave version"
     echo "weave stop"
@@ -126,6 +127,17 @@ stop_masquerading() {
     run_iptables -t nat -X WEAVE >/dev/null 2>&1 || true
 }
 
+docker_ip() {
+    if ! DOCKERIP=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' $CONTAINER_NAME 2>/dev/null) ; then
+        echo "Weave is not running." >&2
+        exit 1
+    fi
+    if [ -z "$DOCKERIP" ] ; then
+        echo "Weave is not running." >&2
+        exit 1
+    fi
+}
+
 # the following borrows from https://github.com/jpetazzo/pipework
 with_container_netns () {
     CONTAINER="$1"
@@ -269,16 +281,19 @@ case "$COMMAND" in
         with_container_netns $CONTAINER attach $CIDR eth0
         echo $CONTAINER
         ;;
+    connect)
+        [ $# -eq 1 ] || usage
+        docker_ip
+        if command_exists curl ; then
+            curl -d peer=$1 $DOCKERIP:$HTTP_PORT/connect
+        else
+            echo "Cannot find curl. Install it for 'weave connect' to function." >&2
+            exit 1
+        fi
+        ;;
     status)
         [ $# -eq 0 ] || usage
-        if ! DOCKERIP=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' $CONTAINER_NAME 2>/dev/null) ; then
-            echo "Weave is not running." >&2
-            exit 1
-        fi
-        if [ -z "$DOCKERIP" ] ; then
-            echo "Weave is not running." >&2
-            exit 1
-        fi
+        docker_ip
         if command_exists wget ; then
             wget -O - -q $DOCKERIP:$HTTP_PORT/status
         elif command_exists curl ; then

weaver/main.go

@@ -141,6 +141,14 @@ func handleHttp(router *weave.Router) {
 	http.HandleFunc("/status", func(w http.ResponseWriter, r *http.Request) {
 		io.WriteString(w, router.Status())
 	})
+	http.HandleFunc("/connect", func (w http.ResponseWriter, r *http.Request) {
+		peer := r.FormValue("peer")
+		if addr, err := net.ResolveTCPAddr("tcp4", weave.NormalisePeerAddr(peer)); err == nil {
+			router.ConnectionMaker.InitiateConnection(addr.String())
+		} else {
+			http.Error(w, fmt.Sprint("invalid peer address: ", err), http.StatusBadRequest)
+		}
+	})
 	address := fmt.Sprintf(":%d", weave.HttpPort)
 	err := http.ListenAndServe(address, nil)
 	if err != nil {