Setting up upstart to run ngrok then to email tunnel info

how-to-upstart-ngrok.md

How to add ngrok to upstart

Dependencies

• upstart (tested on Ubuntu 14.04)
• ngrok
• ssmtp
• jq

ngrok.conf

description "ngrok damon"

start on started docker
stop on runlevel [!2345]

respawn limit 10 5
umask 022

script
    exec /usr/local/sbin/ngrok start --config /etc/ngrok/ngrok.yml --all
end script

post-start script
    # TODO: How do I set this better?
    DEST_EMAIL=<FILL IN>
    OUTPUT="/tmp/cash-money.out"

    # Magic sleep needed. There is some race condition where without this sleep, I never see the echos down
    # below
    sleep 0.5

    while true; do
        response=$(curl --write-out %{http_code} --silent --output /dev/null localhost:4040/api/tunnels)

        if [ $response -eq 200 ]; then
            num_tunnels=$(curl --silent localhost:4040/api/tunnels | jq '.tunnels | length')

            # TODO: Assuming that number of tunnels is greater than 0. Need to verify with the config.
            if [ $num_tunnels -gt 0 ]; then
                echo "Subject: Ngrok arises $(date -u)" > $OUTPUT
                curl --silent localhost:4040/api/tunnels | jq .tunnels | jq 'map(.public_url)' >> $OUTPUT
                ssmtp $DEST_EMAIL < $OUTPUT
                echo "Tunnels are up: $num_tunnels, sent ngrok email"
                break
            else
                echo "No tunnels have been started. Will wait."
            fi
        fi

        # Stole this from docker.conf
        initctl status $UPSTART_JOB | grep -qE "(stop|respawn)/" && exit 1
        echo "Waiting for ngrok to become fully available"
        sleep 0.5
    done
end script