Simple Bash Script that creates a monit config script from your PM2 Processes. Run using ./script.sh [-m YOUR_MONIT_DIR]

Monit Config Creator for PM2 - Better!

#!/bin/bash

# Some utility functions....
trailing_slash () {
    STR="${1}"
    length=${#STR}
    last_char=${STR:length-1:1}
    [[ $last_char != "/" ]] && STR="$monitDir/"; 

    echo $STR;
}
# To style messages for console
styled_echo () {

    case ${2} in
    red)
        text="\e[31m${1}\e[0m"
        ;;
    green)
        text="\e[32m${1}\e[0m"
        ;;
    blue)
        text="\e[34m${1}\e[0m"
        ;;
    yellow)
        text="\e[33m${1}\e[0m"
        ;;
    *)    # default color
        text="\e[39m${1}\e[0m"
        ;;
    esac

    echo -e $text
}


hasMonit=$(command -v monit)
hasJQ=$(command -v jq)

if ((${#hasMonit}==0))
then
    styled_echo "Hey! It doesn't look like monit is  installed! Get it here... https://mmonit.com/monit/" red
    exit 
fi

if ((${#hasJQ}==0))
then
    styled_echo "Hey! This script requires you to install JQ: https://stedolan.github.io/jq/" red
    exit 
fi

while [[ $# -gt 0 ]]
do
    # echo $#

    key="${1}"
    # echo $key

    case ${key} in
    -m|--monit)
        monitDir="${2}"
        ;;
    -h|--help)
        cat << EndOfMessage
Usage: ./pm2-make.sh [options]
Options are as follows:
	-c config     Path to the json configuration file
	-m monit      Path to the monit folder. (Often /etc/monit/)
EndOfMessage
        # shift # past argument
        shift
        ;;
    *)    # unknown option
        shift # past argument
        ;;
    esac
    shift

done

# Use Default Dir
monitDir=${monitDir:-"/etc/monit"}
# Ensure Trailing Slash
monitDir=$(trailing_slash  $monitDir )

# Ensure directory exists else
if [ ! -d "$monitDir" ]; then
  #No need to proceed, stop right here
  styled_echo "The monit folder entered '${monitDir}' does not exist!'" red
  exit 
fi

# Monit Folders
CONF_AVAILABLE_DIR="${monitDir}conf-available/" 
CONF_ENABLED_DIR="${monitDir}conf-enabled/" ;

styled_echo "NOTE: This script uses 'pm2 jlist' command to generate your monit script!"
printf '%*s\n' "${COLUMNS:-$(tput cols)}" '' | tr ' ' -

# Prepare monit config file
MONIT_FILE="${CONF_AVAILABLE_DIR}PM2";
# Drop File if exists
if [ -f $MONIT_FILE ] ; then
    styled_echo "Deleting old monit config file: ${MONIT_FILE}..." red
    rm $MONIT_FILE
fi

styled_echo "Writing monit config file: ${MONIT_FILE}..." blue
echo

# Loop through the processes
echo $(pm2 jlist)  | jq -cr ".[]" | while read o; do
    # Pick name & PID File...
    pid=$(echo $o | jq '.pid' | cut -d'"' -f 2)
    name=$(echo $o | jq '.name' | cut -d'"' -f 2)    
    status=$(echo $o | jq '.pm2_env.status' | cut -d'"' -f 2)
    pid_file=$(echo $o | jq '.pm2_env.pm_pid_path' | cut -d'"' -f 2)

    # echo "${status}";
    if [ "${status}" == "online" ]
    then
        styled_echo "Adding monit config for process '${name}' - [status=${status}]" yellow
        # make monit config command & write to file
        monitCMD="check process PM2-${name} with pidfile '$pid_file'"    
        echo $monitCMD $'\n' >> $MONIT_FILE 
    else
        styled_echo "Skipping monit config for process '${name}' - [status=${status}]" red
    fi

done

printf '%*s\n' "${COLUMNS:-$(tput cols)}" '' | tr ' ' - 
# create symbolic link...
styled_echo "Enabling monit config file ${MONIT_FILE} i.e (symbolic link to ${CONF_ENABLED_DIR})" blue

# Check that symbolink link points to the right file in /conf-available
if [[ -L "${CONF_ENABLED_DIR}PM2" && -f "${CONF_AVAILABLE_DIR}PM2" ]]
then
    # All good!
    styled_echo "Symbolic link exists!" green
else
    if [ -f "${CONF_ENABLED_DIR}PM2" ]        
    then
        # Symbolic link does not point to the right file or is broken, replace
        styled_echo "Replacing symbolic link..." red
        ln -sf $MONIT_FILE $CONF_ENABLED_DIR
    else
        # Symbolic link does not exist. Create
        styled_echo "Creating new symbolic link..." yellow
        ln -s $MONIT_FILE $CONF_ENABLED_DIR
    fi

fi

printf '%*s\n' "${COLUMNS:-$(tput cols)}" '' | tr ' ' -
# Reload Monit
styled_echo "Reloading Monit" blue
monit reload
styled_echo "All Ready!" green

Sample Monit Daemon

#!/bin/bash

#Where
#watchScript=/usr/local/bin/watchfile.sh
#pm2MonitScript=/usr/local/bin/pm2-monit.sh

#command
bash /usr/local/bin/watchfile.sh \ 
      -s "find PM2_HOME/pids/ -type f -print0 | xargs -0 stat" \
      -e /usr/local/bin/pm2-monit.sh > /dev/null &

This Gist is a huge improvement on:

Run using ./script.sh [-m YOUR_MONIT_DIR] for example ./script.sh -m /etc/monit

Note:

• JQ is required to run this script
  -m (if not entered) defaults to "/etc/monit"
  This script uses pm2 ps command and thus will only create config file for processes that are RUNNING on PM2. Also, it only monitors status and does not add stop/start methods. After all, PM2 is a process manager, that's fine. Let PM2 do what it is built to do, i.e manage process restarts and so on.

The script should output something like this

Now go ahead and check out monit...

You can automate this script by using a utility such as watchfile to run whenever PM2 pids change.

./watchfile.sh -s "find /PM2_HOME/pids/ -type f -print0 | xargs -0 stat" -e /PATH_TO_YOUR_SCRIPT/script.sh

See: https://stackoverflow.com/a/25404832