Syncing websites with git

I have been in the tech industry for too long and if I have learned one thing, it is: Documentation is everything.

I have put this blog on github, but I’ve decided that I want it to run on my own server. I’m using ruhoh as blog engine.

My traditional workflow when publishing local work would be this:

• Connect to server via ssh or ftp
• choose correct directory
• create a new “revision”
• ssh into the machine
• ln -s the app to the current revision
• test

With the blog engine I’m using and static content, I can pretty much trust that what I see in my development version will be what I will see at my production version (the one on my server). I don’t have to worry about migrating databases too.

To get started, I copied my whole directory to the server and set up my nginx to serve static pages. But I don’t want to do this every time I do a commit and make it simpler. So my projected workflow looks like this:

• Git commit / push into master for any releases
• Server pulls automatically via cron job
• Server runs “ruhoh compile” after git pull

What can go wrong?

So I want to automate this, so this means i need to think about what happens if… scenarios. But there arn’t that many steps.

• Git pull on the server can fail. But if it does, it has no consequences apart from that the site doesn’t get updated
• There is the possibility of a conflict. At this point I am noticing that I accidently put files in compiled/ into git as well, which might cause such conflct.
• ruhoh compile may fail, for example if filenames in posts/ do not have a properly formatted date. I should test it offline before pushing it.

How I set it up

So, as I said before, I have copied the contents of jglauche.de onto my server to set it up. I did so before I uploaded it to git. It’s located in

/home/jglauche/jglauche.de

So, first thing I need to check is if git pull works.

jglauche@ext01:~/jglauche.de$ git pull
Permission denied (publickey).
fatal: The remote end hung up unexpectedly

Of course. Github does not have a public key from my server. So, let’s check if there’s any ~~~~~~~~ $cd /home/jglauche/.ssh $ls authorized_keys known_hosts ~~~~~~~~

Nope. I need to generate one with

$ssh-keygen

So, this creates two files, by default at id_rsa and id_rsa.pub. First one is the private key, latter is the public key. We need to copy it from the console:

jglauche@ext01:~/.ssh$ cat id_rsa.pub 

You can add keys on github under Settings -> SSH keys. After doing so, I should be able to pull:

jglauche@ext01:~/jglauche.de$ git pull
Already up-to-date.

Yes, that works!

Next step would be to check if ruhoh is installed and if it runs correctly.

jglauche@ext01:~/jglauche.de$ bundle exec ruhoh compile

Yes, works too! I made a small script which I will put in my crontab via

jglauche@ext01:~/jglauche.de$ crontab -e

*/20 * * * * /home/jglauche/jglauche.de/update_site.sh

So for now I will have it try to update every 20 minutes.

Notes

• The shell script is stupid and will re-compile the site every time, even if there was no change. I am currently fine with that, but I might change that behaviour at a later time.
• I still have the compiled directory inside the github, I should remove that at a later time.