Add detach command

weaver/weave

@@ -6,6 +6,7 @@ usage() {
     echo "weave launch <ipaddr>/<subnet> [-passwd <passwd>] <peer_host> ..."
     echo "weave run    <ipaddr>/<subnet> <docker run args> ..."
     echo "weave attach <ipaddr>/<subnet> <container_id>"
+    echo "weave detach <container_id>"
     echo "weave expose <ipaddr>/<subnet>"
     echo "weave hide   <ipaddr>/<subnet>"
     echo "weave status"
@@ -102,7 +103,7 @@ stop_masquerading() {
 }
 
 # the following borrows from https://github.com/jpetazzo/pipework
-configure_container_networking() {
+find_container_pid() {
     DOCKERPID=$(docker inspect --format='{{ .State.Pid }}' $1)
     [ "$DOCKERPID" = 0 ] && {
         echo "Container $1 not running." >&2
@@ -112,6 +113,11 @@ configure_container_networking() {
         echo "Container $1 unknown to Docker." >&2
         exit 1
     }
+	return 0
+}
+
+configure_container_networking() {
+	find_container_pid $1
     NSPID=$DOCKERPID
 
     [ ! -d /var/run/netns ] && mkdir -p /var/run/netns
@@ -154,6 +160,15 @@ configure_container_networking() {
     return $EXITCODE
 }
 
+takedown_container_networking() {
+	find_container_pid $1
+    NSPID=$DOCKERPID
+
+    LOCAL_IFNAME="v${CONTAINER_IFNAME}pl${NSPID}"
+
+    ip link del $LOCAL_IFNAME type veth || true
+}
+
 case "$COMMAND" in
     launch)
         [ $# -gt 0 ] || usage
@@ -236,6 +251,12 @@ case "$COMMAND" in
         shift 1
         configure_container_networking $CONTAINER $IPADDR $CONTAINER_IFNAME
         ;;
+    detach)
+        [ $# -gt 0 ] || usage
+        CONTAINER=$1
+        shift 1
+        takedown_container_networking $CONTAINER
+        ;;
     expose)
         [ $# -gt 0 ] || usage
         IPADDR=$1