Automating the Fracturing of a Git Repository

I have a git repo that’s become a monster. It’s got at least two WordPress themes, a handful of custom WordPress plugins, some .htaccess files, an artwork directory, and more. Back in the dark times, when it was a Subversion repository this sort of made sense, in that I didn’t have to set up a new repo on the server for each component in the project. But I haven’t touched SVN in a long time, and making new repositories in Git is easy. We’re doing some major work on this client’s sites this fall, so it’s time to break up the giant repository into several smaller ones.

The monolith repository is being split into seventeen smaller components. One of these components is an “artwork” directory, the ~600MB history of which will bloat the git history of all sixteen other repositories if we don’t purge it properly. The goals of this script are:

  1. Avoid typing the same set of commands seventeen times.
  2. Keep the appropriate git history for each of the seventeen components.
  3. Purge any unrelated git history so each component only has its own history in its .git directory.

Github has a help page on splitting a subfolder into its own repository, and another on removing files from a repository’s history, (it’s meant for sensitive data, but works for all data). In theory we only really need the first link, but in testing the entire history of the monolith remained when only following the instructions in the first link, but with the purge and garbage collection commands from the second link the git history is down to an appropriate size.

The script is relatively simple, but relies a bit on directory structure. It should be in the same directory as the monolith repo, (the script doesn’t go into the monolith, it goes in the same containing folder). There are two places to change the script:

  1. Put the directories for extraction into the repos array, (starting on line 5). These paths are relative to the root of the repository.
  2. Put the path of a copy of the monolith repo for use as a source in the master variable, (line 16).

Once that’s done, running ./export-directory-repos.sh should export the repositories.

Here’s the gist:

 

 

A PHP Version Switcher for the AMP stack on OS X

A friend is thinking about buying MAMP Pro so he can test on different versions of PHP. Since I just set up version-switching myself, for free, here’s how I did it. Hopefully it’ll save someone a bit of money or frustration.

This is happening on a Mac, with the latest version of OS X, (Currently 10.11.3 El Capitan), using the pre-installed version of Apache, and Homebrew as a package manager.

Step 1: Install more than one version of PHP on your system

Using Homebrew you can install a version of PHP, then “unlink” it so it’s not currently being used:

brew install php7
brew unlink php7

If you want to be able to switch PHP versions on the command-line there’s a tool called PHP Version that does the heavy lifting for you, and with Homebrew it’s easy to install.

Step 2: Make it easy to change the PHP version Apache is using

First, stop the main Apache config, (/etc/apache2/httpd.conf), file from loading PHP. Find any line that mentions PHP modules and comment it out, (put a # at the beginning of the line). For example:

#LoadModule php5_module libexec/apache2/libphp5.so
#LoadModule php5_module /usr/local/opt/php56/libexec/apache2/libphp5.so

Now we need an Apache config file for each PHP version that you want to run. I’ve put these files in /etc/apache2/other/ and used the file extension “.conffile” to prevent Apache from auto-loading them:

A screenshot of /etc/apache2/conf/other

Each of your .conffile files needs to have the location of the PHP library, and any extra PHP info. This is the contents of my php-7.conffile:

LoadModule php7_module /usr/local/opt/php70/libexec/apache2/libphp7.so
<IfModule php7_module>
    AddType application/x-httpd-php .php
    AddType application/x-httpd-php-source .phps
</IfModule>
<IfModule dir_module>
    DirectoryIndex index.html index.php
</IfModule>

php-5.conffile is very similar, but has the path of the PHP 5 .so file and the IfModule conditional checks for php5_module.

If you have any existing php*.conf files in /etc/apache2/other/ they can be blank.

Next we need to make an easy way to tell Apache to use one of the .conffiles, which I’ve  done by creating a symbolic link to the one I want to use. Since I don’t like typing out ln commands I’ve created a script, which I call php-v.sh.

#!/bin/bash
if [ $1 = 7 ]; then
PHP_VERSION=7
else
PHP_VERSION=5
fi
`sudo ln -Fs /etc/apache2/other/php-$PHP_VERSION.conffile /etc/apache2/other/php.conf`
`sudo apachectl graceful`
echo "PHP version switched to $PHP_VERSION"

This script symlinks /etc/apache2/other/php.conf to the .conffile that I want to use, (using the -F switch to overwrite the old symlink), and restarts Apache. It needs sudo so it’ll ask for your password.

Finally, it’s nice to have php-v.sh available from everywhere, so I’ve created a symlink from ~/bin/php-v, which is in my PATH, to the actual script:


ln -s /Users/John/Developer/Scripts/php-v.sh /Users/John/bin/php-v

And now I can switch PHP versions at will:A screenshot of my terminal, having just switched PHP versions quickly & easily!