Recently, I encountered node application always crash. I tried to avoid the crash and handle the error in code but it’s not sufficiency, so I ended up decided to create a schedule in our server to check if the node application service running. If it does not run we’re run it.

I’ll divide the the task into two steps. First, create a bash script to check the node application. Second, create a cron schedule.

Now let’s assume that you have a node application which locate in /home/user/example_app/index.js

1. Create a bash script:

##cd to application directory

– cd /home/user/example_app/

##create a run_node.sh file

– sudo touch run_node.sh

##give the permission for file to executable

– sudo chmod a+x

##open the file in vim text editor

– sudo vim run_node.sh

## and copy the following code, the script below check if node application is running, if it not then run it.

#!/bin/sh
APP_PATH= “/home/user/example_app/”
NAME=”index.js”

RESULT=`pgrep -f $NAME`

if [ “${RESULT:-null}” = null ]; then
nohup node $APP_PATH$NAME &
fi

2. Create a cron schedule:

## Check your cron task on current user

– crontab -l

## Open new config

– crontab -e

## Add the following config

*/10 * * * * cd /home/user/example_app && sudo mkdir -p cron-log && sudo sh run_node.sh>>cron-log/`date +\%Y\%m\%d`-cron.log

## The above line do three things, go to application folder, create a cron-log folder if not exists, then run our bash script to check the node application and out put the error in cron-log folder.

## Restart cron

– sudo service cron restart (Ubuntu) or sudo service crond restart (centOS)

Check the screenshot below:

#run_node.sh

#crontab -e