Checks to see if alpaca proxy is running, restarts accordingly on network changes

check_alpaca.sh

#!/usr/bin/env bash

# Script to restart/start alpaca on network changes.
#
# To register plist:
# launchctl load network_change.plist
# launchctl start network_change

#
# Vars
BIN="/usr/local/bin/alpaca"
DNS_SERVER="1.1.1.1"
FILE="/etc/resolv.conf"
PAC="http://some_proxy_server:8080/some_pac_file.pac"
PROCESS="alpaca"

#
# Functions

function do_alert {
    local title=$1
    local message=$2

    osascript -e "display notification \"$message\" with title \"$title\""
}

function check_file_contents {
    local contents=$1
    local file=$2

    echo "===> Checking $file for $contents"
    # sleep 3
    grep -q $contents $file
}

function check_process {
    local process=$1

    echo "===> Checking process: $process"
    if pgrep -x $process >/dev/null
    then
        # 0 = true
        return 0
    else
        return 1
    fi
}

function kill_process {
    local process=$1

    echo "===> Killing process: $process"
    pkill $process
}

function start_alpaca {
    local bin=$1

    echo "===> Starting binary: $bin"
    $bin
    do_alert "Alpaca" "Started $PROCESS at 🏠 home"
}

function start_alpaca_at_work {
    local bin=$1
    local pac=$2

    echo "===> Starting binary: $bin"
    $bin -C $pac
    do_alert "Alpaca" "Started $PROCESS at 🏭 work"
}

#
# Main
echo "===> Network change detected..."

if check_file_contents $DNS_SERVER $FILE
then
    echo "===> Welcome home"
    echo "===> Getting process: $PROCESS"
    if check_process $PROCESS
    then
        echo "===> Restarting process: $PROCESS"
        kill_process $PROCESS
        start_alpaca $BIN
    else
        start_alpaca $BIN
    fi
else
    echo "===> Off to work we go..."
    echo "===> Getting process: $PROCESS"
    if check_process $PROCESS
    then
        echo "===> Restarting process: $PROCESS"
        kill_process $PROCESS
        start_alpaca_at_work $BIN $PAC
    else
        start_alpaca_at_work $BIN $PAC
    fi
fi