Kill all ssh tunnels gracefully at expose_ports.sh

Author: elgalu

host-scripts/expose_ports.sh

@@ -16,14 +16,25 @@ die () {
   exit $errnum
 }
 
+# ensures supervisord dies too
+shutdown () {
+  echo "Trapped SIGTERM/SIGINT/SIGKILL so shutting down expose gracefully..."
+  kill -SIGTERM $(jobs -p)
+  exit 0
+}
+
 # Required params
 [ -z "${1}" ] && die "Need at least 1 port number argument!"
 MYAPP_PORTS=$@
 
 [ -z "${CONTAINER_IP}" ] && die "Need environment variable \$CONTAINER_IP set!"
 [ -z "${SSHD_PORT}" ] && die "Need environment variable \$SSHD_PORT set!"
 [ -z "${KNOWN_HOSTS_PATH}" ] && die "Need env var \$KNOWN_HOSTS_PATH set!"
-BASE_SSH_CMD="-p ${SSHD_PORT} -o StrictHostKeyChecking=no -N -fn application@${CONTAINER_IP}"
+# -f  Requests ssh to go to background just before command execution
+# -n  Redirects stdin from /dev/null (actually, prevents reading from stdin).
+#     This must be used when ssh is run in the background
+# -N  Do not execute a remote command.  This is useful for just forwarding ports
+BASE_SSH_CMD="-p ${SSHD_PORT} -o StrictHostKeyChecking=no -N -n application@${CONTAINER_IP}"
 
 ## convert space separated string into a bash array
 IFS=' ' read -a MYAPP_PORTS <<< "${MYAPP_PORTS}"
@@ -32,7 +43,13 @@ declare -a MYAPP_PORTS=${MYAPP_PORTS}
 # to setup tunnels first kill existing tunnels if any
 # then set them up in the background
 for i in "${MYAPP_PORTS[@]}"; do
-  kill $(lsof -i tcp:${i} -F p | cut -b 2-) >/dev/null 2>&1 || true
-  ssh-keygen -f "${KNOWN_HOSTS_PATH}" -R [${CONTAINER_IP}]:${SSHD_PORT} >/dev/null 2>&1 || true
+  (kill $(lsof -i tcp:${i} -F p | cut -b 2-) >/dev/null 2>&1) || true
+  (ssh-keygen -f "${KNOWN_HOSTS_PATH}" -R [${CONTAINER_IP}]:${SSHD_PORT} >/dev/null 2>&1) || true
   ssh ${BASE_SSH_CMD} -R localhost:${i}:localhost:${i} &
 done
+
+# Run function shutdown() when this process a killer signal
+trap shutdown SIGTERM SIGINT SIGKILL
+
+# tells bash to wait until child processes have exited
+wait