Note: I found this mini How-To while having a clean-up of my GitHub repositories. I figured it would be worth sharing on my blog. Hopefully it is of use to someone. Warning: bad ASCII art ahead!


The Problem

  1. I have my repository hosted on GitHub
  2. I have an internal Git server used for deployments
  3. I want to keep these synchronised using my normal workflow

Getting Started

Both methods I’ll describe need a “bare” version of the GitHub repository on your internal server. This worked best for me:

cd ~/projects/repo-sync-test/
scp -r .git user@internalserver:/path/to/sync.git

Here, I’m changing to my local working directory, then using scp to copy the .git folder to the internal server over ssh.

More information and examples this can be found in the online Git Book:

4.2 Git on the Server – Getting Git on a Server

Once the internal server version of the repository is ready, we can begin!

The Easy, Safe, But Manual Method:

+---------+ +----------+ /------>
| GitHub  | | internal | -- deploy -->
+---------+ +----------+ \------>
^                     ^
|                     |
|     +---------+     |
\-----|   ME!   | ----/
      +---------+

This one I have used before, and is the least complex. It needs the least setup, but doesn’t sync the two repositories automatically. Essentially we are going to add a second Git Remote to the local copy, and push to both servers in our workflow:

In your own local copy of the repository, checked out from GitHub, add a new remote a bit like this:

git remote add internal user@internalserver:/path/to/sync.git

This guide on help.github.com has a bit more information about adding Remotes.

You can change the remote name of “internal” to whatever you want. You could also rename the remote which points to GitHub (“origin”) to something else, so it’s clearer where it is pushing to:

git remote rename origin github

With your remotes ready, to keep the servers in sync you push to both of them, one after the other:

git push github master
git push internal master
  • Pros: Really simple
  • Cons: It’s a little more typing when pushing changes

The Automated Way:

+---------+            +----------+ /------>
| GitHub  |   ======>  | internal | -- deploy -->
+---------+            +----------+ \------>
^
|
|              +---------+
\------------- |   ME!   |
               +---------+

The previous method is simple and reliable, but it doesn’t really scale that well. Wouldn’t it be nice if the internal server did the extra work?

The main thing to be aware of with this method is that you wouldn’t be able to push directly to your internal server – if you did, then the changes would be overwritten by the process I’ll describe.

Anyway:

One problem I had in setting this up initially, is the local repositories on my PC are cloned from GitHub over SSH, which would require a lot more setup to allow the server to fetch from GitHub without any interaction. So what I did was remove the existing remote, and add a new one pointing to the https link:

(on the internal server)
cd /path/to/repository.git
git remote rm origin
git remote add origin https://github.com/chrismcabz/repo-syncing-test.git
git fetch origin

You might not have to do this, but I did, so best to mention it!

At this point, you can test everything is working OK. Create or modify a file in your local copy, and push it to GitHub. On your internal server, do a git fetch origin to sync the change down to the server repository. Now, if you were to try and do a normal git merge origin at this point, it would fail, because we’re in a “bare” repository. If we were to clone the server repository to another machine, it would reflect the previous commit.

Instead, to see our changes reflected, we can use git reset (I’ve included example output messages):

git reset refs/remotes/origin/master

Unstaged changes after reset:
M LICENSE
M README.md
M testfile1.txt
M testfile2.txt
M testfile3.txt

Now if we were to clone the internal server’s repository, it would be fully up to date with the repository on GitHub. Great! But so far it’s still a manual process, so lets add a cron task to stop the need for human intervention.

In my case, adding a new file to /etc/cron.d/, with the contents below was enough:

*/30 * * * * user cd /path/to/sync.git && git fetch origin && git reset refs/remotes/origin/master > /dev/null

What this does is tell cron that every 30 minutes it should run our command as the user user. Stepping through the command, we’re asking to:

  1. cd to our repository
  2. git fetch from GitHub
  3. git reset like we did in our test above, while sending the messages to /dev/null

That should be all we need to do! Our internal server will keep itself up-to-date with our GitHub repository automatically.

  • Pros: It’s automated; only need to push changes to one server.
  • Cons: If someone mistakenly pushes to the internal server, their changes will be overwritten

Credits

I received an email from a developer the other day, who had forked the repository for my “IIS Express Here” shell extension on GitHub [editors note – no longer available]. He had noticed there was no license information available in the project, so asked if I could either add a license, or give him written permission to adapt my code and share it to others (as is the spirit of GitHub and OSS).

To be honest, this wasn’t something I’d thought about before, and was a bit of an oversight on my part. I’d not really considered the need to add explicit licenses to my repositories. After all, the code is out there anyway – it’s open to use on GitHub, and I’ve often shared it on this blog‚Ķ if someone wanted to copy the code, they could, right?

Unfortunately, this creates a grey-area, which some are naturally uncomfortable with. Can I use this code in something else? Can I modify it at all? Do I have to pay royalties if I do?

But licensing is hard, isn’t it? All the different types, with different caveats, liabilities, and legal mumbo-jumbo‚Ķ well, yes, it can be hard. The good folks at GitHub have a solution:¬†ChooseALicense.com is attempting to demystify open source licenses so you can pick the right one for your project. More than this, when you create a new repository on GitHub, the site will ask if you want to add a template license during the initialisation process:

repo_licenses

Coming back to the developer who emailed me – I mailed him back to let him know that IIS Express Here is now licensed under the MIT¬†license. This fits best with how I see the code and projects I share on this blog (unless noted otherwise) – free for anyone else to use, but with no warranty, so if something goes wrong then I’m not liable and it’s not my responsibility to fix it. I haven’t got around to updating all of my repos with licenses, as I’m evaluating each one in turn, based on my goals and even whether the project is going to archived.

ChooseALicense.com

Skills are much like muscles: if you don’t use them for a while they start to atrophy. They say you never forget how to ride a bike, but there are many skills where you¬†will forget things if you don’t do them frequently. The collection of skills needed to be a developer are no exception to the rule.

I’m somewhat speaking from experience here; my current role and workload has removed me from day-to-day development work for about a full year now. I still need to dive in to the code base every day to research issues or change requests, but actually writing something is quite rare these days. I’m aware of the skills problem, and I’ll describe below how I’m trying to address it, but never the less I’ve been self-concious enough about it I’ve recently found myself resisting taking on development tasks. I know it’ll take me a lot longer to get up to speed and complete as one of the developers who’re working on the application every day, and the time-scales involved are usually very tight. It’s a vicious circle: I’m rusty because I’m not doing development, but I’m avoiding development because I’ve been away from it for too long. In the corporate world it’s very easy to get rail-roaded into a niche – and incredibly hard to get out of it.

Time away for a developer is exacerbated by the speed in which technology and techniques moves forward in our industry. What was cutting edge a year-ago is old-hat today, and may even be something you’re encouraged¬†not to do any more. If you haven’t been practising and keeping up developments then you may not be aware and get yourself into all sorts of bother.

So what can you do?

Read. Lots.

Subscribe to a load of developer sites and blogs in Feedly, for one source, but a more convenient way I’ve found to stay on top of things is using Flipboard:

  • Follow other developers on Twitter (actually, you don’t have to, but it’s nice to), and create/add them to a list, such as “Developers & News“.
  • Within Flipboard, add your Twitter account if you haven’t already.
  • Still within Flipboard, go to your Twitter stream. Tap your name at the top and select “Your Lists.”
  • Open the relevant list, then tap the subscribe button.

Your list will be added to your Flipboard sources and you’ll have an always-up-to-date magazine of what’s happening. The reason I suggest Flipboard is that it grabs the link in a tweet, pulls in the article, and will try to reformat it into something you can easily flip through. It makes reading on a tablet so much more enjoyable. Some of the links you get will not be relevant, but a large amount of it will be gold. I try to set aside 30 minutes a day to go through at least the headlines.¬†If work is exceptionally busy I’ll aim for twice a week.¬†Saving to a “Read it Later” service like¬†Pocket¬†is useful for storing the most interesting articles.

What about books? Yes, by all means, read plenty of technical books. They’re usually in far more depth than even the best online article. With tablets, eReaders, and eBooks, the days of thick tomes taking up lots of space are behind us, and no longer a major concern (at least for me). There is however, one major issue with books – they take a long time to write, and are often out of date quickly. The technology might have moved on by the time the book is published. Schemes such as the Pragmatic Programmer’s “Beta Book” scheme help a lot here – releasing unfinished versions of the book quickly and often, to iron out problems before publishing. Of course, you also need to be aware of the topic to be able to pick out a book about it!

Be Curious. Experiment.

Reading all the material in the world will not help you anywhere near as much as actually¬†doing something.¬†The absolute best thing you could do would be to develop side projects in your spare time. Admittedly, if you’re busy, time can be at a premium! Probably a good 99% of side projects I start lie unfinished or abandoned, simply for lack of time.¬†So instead, I perform small experiments.

Curious about something? Do something small to see how it works, or “what happens if…”. Personal, recent, examples would be:

  • Looking into static site generators, and as a result, learning about Jekyll, Github pages for hosting… and as a result of trying out Jekyll templates I brushed up on Responsive Web Design, looked into Zepto, and fell in love with¬†Less.
  • Trying out automating development workflows – installed Node.js (which then allowed me to run this), setup some basic Grunt.js tasks, Imagemagick batch processing, and some more Less.
  • Running Linux as my primary OS, and no Windows partition to fall back on – so in at the deep-end if something goes wrong… but it’s helped me brush up on my MySQL and Apache admin skills again, as well as generally working with the command-line again. The other week I fixed someone’s VPS for them via SSH ¬†– something I would have struggled to do only a few weeks ago. In case you’re interested: the disk was filling up due to an out of control virtual host error log, which I had to first diagnose, and then reconfigure logrotate to keep the site in check.

An earlier example, from before I was entirely away from development: I wanted to see what was different in CodeIgniter 2, so I made a very small app. My curiosity then extended into “how does Heroku work?” – so I deployed to Heroku. I couldn’t pay for a database I knew how to work with, so I tried out a little bit of MongoDB. Then it was the Graph API from Facebook… so again, I extended the application, this time with the Facebook SDK.

Little experiments can lead to a lot of learning. I would never claim to be an expert in any of the technologies I mention, but neither am I ignorant.

Shaking it Out

I’d still need a major project to focus on and really shake off the “ring rust,” to get back up to full development potential, but I’m pretty confident it wouldn’t take as long as if I hadn’t been working on the trying to keep my skills as fresh as I can.