How to prompt the user on which service to take an action on

action.sh

#!/bin/bash

to_siege=`action-get service` # could be unit instead, but service seems better
siege_rid=""

rids="$(relation-ids website)"

if [ $(echo $rids | wc -l ) -eq 0 ]; then
  action-fail "Siege is not related to anything, can not benchmark nothing"
fi

for rid in "$rids"; do # not sure if rids needs to be quoted...
  unit=$(relation-list -r $rid | head -n1)
  service=${unit%%/*}
  if [ $service == $to_siege ]; then
    siege_rid=$rid
    break
  fi
done

if [ -z "$siege_id" ] && [ $(relation-ids website | wc -l) -gt 1 ]; then
  action-fail "Unable to determine which source to siege"
fi

if [ -z "$siege_id" ]; then
  siege_id="$rids"
fi

urls=""

for unit in $(relation-list -r $rid); do
  urls="$urls\nhttp://$(unit-get -r $rid private-address $unit)"
done

# Write urls to a urls.txt file and use it to hit all heads

# do siege with the URLS.txt set