Add ngrok startup script.

README.md

@@ -1,4 +1,4 @@
-# Workstation Housekeeping v1.8
+# Workstation Housekeeping v1.9
 
 Scripts to manage data on the NGS workstation
 
@@ -66,3 +66,20 @@ wscleaner ROOT_DIRECTORY --logfile LOGFILE_PATH
 ```
 
 ---
+
+## ngrok_start.sh
+
+Allow SSH access to the system by running ngrok as a background process.
+
+### Installation
+
+See knowledge base article for ngrok installation.
+
+### Usage
+
+```bash
+$ ngrok_start.sh
+"tcp://30.tcp.eu.ngrok.io:5555"
+```
+
+---

ngrok_start.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+# ngrok_start.sh - A script to allow SSH access to the system by running ngrok as a background process
+#   Prints SSH details if ngrok is already running.
+#   Note: The ngrok process can be closed at anytime with `kill $(pidof ngrok)`
+
+# Get the process ID of ngrok if it is already running on the system
+EXISTING_PROCESS=$(pidof ngrok)
+
+if [ -z $EXISTING_PROCESS ] ;then
+  # If ngrok is not running, start as a background process and print the url for SSH access
+  #   nohup [command] : Keep the process running the command even after you quit the session
+  #   ngrok tcp --region eu 22 : Open an connection to ngrok server on port 22
+  #   &> /dev/null : Discard stdout and stderr to empty output stream
+  #   & : Run as a background process
+  nohup ngrok tcp --region eu 22 &> /dev/null &
+  # Pause for a few seconds to allow the connection to complete.
+  sleep 3
+  # Write the ngrok public url for SSH access to the syslog.
+  #   Triggers alert in slack with ssh url details and writes to stderr.
+  NGROK_URL=$(curl http://localhost:4040/api/tunnels 2>/dev/null | jq ".tunnels[0].public_url")
+  logger -s "ngrok_start - new workstation host - $NGROK_URL"
+else 
+  # If ngrok is already running, print the public url for SSH access to stderr
+  NGROK_URL=$(curl http://localhost:4040/api/tunnels 2>/dev/null | jq ".tunnels[0].public_url") 
+  echo "ngrok_start - $NGROK_URL" 1>&2
+fi