Creating a backup system with Runlet

In this post I will go through a quick overview of how to manage and run jobs from the command line using Runlet CLI. If you haven’t installed Runlet yet, I recommend you go to the releases page and check out our latest release that best fits your platform (Windows, Mac or Linux). Once installed you’ll need to sign in to link the newly installed daemon to your account.

runlet @signin

The QR code is useful if you are on a device with no browser. You can then use your mobile phone to authorize the daemon without having to type boring URLs. Once signed in you will be able to add or remove jobs.

Creating a scheduled job

The first job that we’ll create for our backup system will be responsible to compact and upload a bunch of important files to our backup server. We can create a job from the command line with the following line:

runlet @config

If you’re using Linux you must run as root

sudo runlet @config

This will open your editor defined in $EDITOR (Defaults to nano) with the correct configuration file. After closing the file will be merged with the current configuration and synced with the other connected daemons in your account.

Let’s define our job as follows:

backup:
  script: |
    src=/myproject
    hash=$(echo -n $src | md5sum | cut -c-32)
    timestamp=$(date +"%m-%d-%Y-%H-%M")
    dest="/tmp/$hash-$timestamp.tar.gz"
    tar -zcvf $dest $src
    cp $dest /backups
  every: 0 16 * * *

Now save and close the file.

This will create a job called backup that will run every day at 4pm. It works by compacting /myproject and storing the binaries at /backups.

note

Note that this job will run on every connected daemon at the specified time.

If you want to manually run the job you can call like this:

runlet @run backup

You should expect a file created at /backups.

Automating backup of arbitrary directories

But what if we want to backup arbitrary directories? We can do that using job arguments. By passing arguments you can change the behavior of a job before executing it. We use Golang’s strong template engine to process every job script.

Change the job to:

backup:
  script: |
    {{ if gt (len .Args) 1 }}
    src="{{ index .Args 1 }}"
    {{ else }}
    src="/myproject"
    {{ end }}

    hash=$(echo -n $src | md5sum | cut -c-32)
    timestamp=$(date +"%m-%d-%Y-%H-%M")
    dest="/tmp/$hash-$timestamp.tar.gz"
    tar -zcvf $dest $src
    cp $dest /backups
  every: 0 16 * * *

As we can see on line 3 we check if there are any arguments passed during the call. If we have, we use it as src, otherwise we defaults to /myproject. We can then call from the command line like this:

runlet @run backup /myproject/node_modules

We will then backup only the selected directory.