Enabling run.sh to work with busybox 'ash'

[PhracturedBlue]

I am trying to use the run.sh script on Alpine linux (which uses busybox). I ran into 2 issues with the run.sh script:

1. Busybox 'ash' does not have arrays like bash does
2. Busybox tail does not support the --pid argument
3. Busybox 'trap' does not properly handle 'EXIT' signals

I fixed (1) by manually splitting the $LAN_PARENT, and (2) by using 'docker wait'. I haven't found a good solution for (3) yet. using trap _cleanup EXIT INT TERM doesn't seem to work either. Even if I end up installing bash, the fix for (2) is still needed though.

diff --git a/run.sh b/run.sh
index a09bf3a..88c06f3 100755
--- a/run.sh
+++ b/run.sh
@@ -172,9 +172,10 @@ _prepare_network() {
 			LAN_IFACE=br-${LAN_ID:0:12}
 
 			# test if $LAN_PARENT is a VLAN of $WAN_PARENT, create it if it doesn't exist and add it to the bridge
-			local lan_array=(${LAN_PARENT//./ })
-			if [[ ${lan_array[0]} = $WAN_PARENT ]] && ! ip link show $LAN_PARENT >/dev/null 2>&1 ; then
-				sudo ip link add link ${lan_array[0]} name $LAN_PARENT type vlan id ${lan_array[1]}
+			local lan_parent_iface=$(echo $LAN_PARENT | cut -d. -f1)
+			local lan_parent_vlan=$(echo $LAN_PARENT | cut -d. -f2)
+			if [[ ${lan_parent_iface} = $WAN_PARENT ]] && ! ip link show $LAN_PARENT >/dev/null 2>&1 ; then
+				sudo ip link add link ${lan_parent_iface} name $LAN_PARENT type vlan id ${lan_parent_vlan}
 			fi
 			sudo ip link set $LAN_PARENT master $LAN_IFACE
 		;;
@@ -220,4 +221,4 @@ main() {
 
 main
 trap "_cleanup" EXIT
-tail --pid=$pid -f /dev/null
+docker wait $CONTAINER

[oofnikj]

This is a great idea. I'll have to play with this when I get some time.

Is there no way you can install bash?
Perhaps we could use sed or awk to do some of the string manipulation instead of relying on arrays?

[PhracturedBlue]

Yes, I could install bash, but I'm trying to keep the set of installed packages on the base image at an absolute minimum (just enough to run docker).
You only have a single bash array (that I've run into) today and the 'cut' method above seems to work to eliminate it.

[gaby]

@PhracturedBlue Everytime I run into this issue, just installing bash fixes everything