Auto Version Control Your Files with incron

24 July 2022

This article's intention is to provide instructions on setting auto version control for a given location. If you want to learn more about incron I suggest you visit the official page and github.

To follow along I have prepared a Dockerfile you can use to build an image, you can then use to spin a container:
ℹ️ you should have Docker installed

FROM ubuntu:22.04
RUN apt-get update
RUN apt-get -y install incron
RUN apt-get -y install git

After you save the file run the following:

# Create image
docker build -t auto-version-control-demo .
#Start and enter in container
docker run -it --entrypoint bash auto-version-control-demo

I've given my image the name of auto-version-control-demo, you can call yours whatever you like.

By now you are already in the running container, incron is installed and you just have to update /etc/incron.allow before starting the service:

echo 'root' >> /etc/incron.allow

Now you can start the service:

/etc/init.d/incron start
* Starting File system events scheduler

Your incron service is running now. You can confirm by:

/etc/init.d/incron status
* incron is running

After the start of the service we have to create a new entry for the root user. Currently there are none:

incrontab -l
no table for root

To create new entry we need the following:

<path>  <mask>  <command>

Where path is the location of the file or folder on the machine we want to monitor, the mask is the event we want to listen for and the command is the action we want to apply. In this demo we want to monitor the /cdn/content folder. The events we want to listen for are IN_MODIFY, IN_CREATE, IN_DELETE, IN_MOVE and we want to run the commands from a bash script which we'll call cdn-auto-version.sh and place in the / root folder. The content of the cdn-auto-version.sh will be:

#!/bin/bash

PROJECT_FOLDER=/cdn/content

cd $PROJECT_FOLDER
git pull
git add .
git commit -m "Updated on $(date +'%d-%m-%y') at $(date +'%T') UTC"
git push

Next we have to make the script, executable. Make sure you're in the root folder:

cd /
chmod 755 cdn-auto-version.sh

ℹ️ You will also have to add ssh keys in /.ssh for the repository you will be working with. I am not going to touch on this in the article but there is plenty of material in Google on how to do this.

With all this done we are ready to create our incrontab entry. Execute:

incrontab -e

This will open the vim text editor. Press the i key an paste:

/cdn/content IN_MODIFY,IN_CREATE,IN_DELETE,IN_MOVE /cdn-auto-version.sh

Hit Esc and then type :x and Enter. This will save your changes:

table updated

To ensure you have updated the table:

incrontab  -l
/cdn/content	IN_MODIFY,IN_CREATE,IN_DELETE,IN_MOVE	/cdn-auto-version.sh

With this /cdn/content will automatically update the remote repo you've set up every time there are changes to the files or folders within.

I have used this post as a reference on how to set up and work with incron:
https://www.geeksforgeeks.org/incron-command-in-linux-with-examples/