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I’m loving using Mephisto as my blog engine. Justin has done great work on the interface and Rick’s code is of his usual standard. There’s a lot more great stuff to come which I’m really looking forward to. In fact I’m loving Mephisto so much I’ve decided to use it as the blogging engine on a client project. This project doesn’t require very advanced blogging, but it does require that it’s integrated with the main site with seamless user registration and multiple sites. I’ll write more about that when I do it, but first I want to show how I setup my development environment so I can track changes to Mephisto trunk, make any local changes I require and deploy using Capistrano.

My requirements were:

• Have multiple local copies of Mephisto I can make versioned changes to
• Merge upstream changes from the Mephisto trunk into my local versions
• Be able to deploy with Capistrano

I initially tried this with darcs, but came to the conclusion that svk was a better choice as it works better with Subversion. I’ll go through the process of how I set this up here, I’m assuming there’s no local SVK repos already setup. If there is you may have to modify the steps below to fit.

First up is setting up an svk mirror of the Mephisto trunk. I ran the following to setup the mirror to pull from:

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    $ svk mkdir //pull_repositories
    Repository /Users/chris/.svk/local does not exist, create? (y/n)y
    $ svk mkdir //pull_repositories/mephisto
    $ svk mirror http://svn.techno-weenie.net/projects/mephisto/trunk  //pull_repositories/mephisto/trunk
    $ svk sync //pull_repositories/mephisto/trunk
    Syncing http://svn.techno-weenie.net/projects/mephisto/trunk    
    ... lots of output ...
  

Syncing the Mephisto repository will take a while the first time you do it. The next step is to create a local svk branch to use. I tested this process out with my personal blog so I’m going to create a local branch called personal.

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    $ svk mkdir //local
    $ svk mkdir //local/mephisto
    $ svk cp //pull_repositories/mephisto/trunk //local/mephisto/personal
  

So now there’s a local copy you can checkout with svk co //local/mephisto/personal, make changes to and checkin with svk ci. See the installation instructions on the Mephisto wiki for how to proceed.

We won’t be able to deploy this yet, as Capistrano doesn’t support svk. What’s needed is the ability to push the local branch out to another subversion repository that Capistrano can use for deployments. You’ll need to make a new subversion repo wherever you usually keep them.

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    $ svk mkdir //push_repositories
    $ svk mkdir //push_repositories/mephisto
    $ svk mirror (url to your svn repo) //push_repositories/mephisto/personal
    $ svk smerge --baseless //local/mephisto/personal //push_repositories/mephisto/personal
  

You can checkout the subversion repo with svn and you’ll see a copy of your local branch. You use this repository as your repo in your deploy.rb.

To help with the svk stuff and all for automatically pushing the latest local changes to the subversion repo when deploying, I created a lib/tasks/svk.rake that looks like:

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    app_name = File.basename(File.dirname(Dir.pwd))
    install_name = File.basename(Dir.pwd)

    local_repo = "//local/#{app_name}/#{install_name}"
    push_repo = "//push_repositories/#{app_name}/#{install_name}"

    namespace :svk do
      desc "Get latest from upstream"
      task :pull do
        system("svk pull")
      end

      desc "Push local svk branch to remote svn"
      task :push do
        system("svk smerge --incremental --log #{local_repo} #{push_repo}")
      end
    end    
  

And added the following task to my deploy.rb¹

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    desc "Push the latest svk code to the svn repo and set the svn revision number"
    task :before_update_code do
      system("rake svk:push")
    end
  

That should be everything setup. You can now hack away on Mephisto to your hearts content in as many different branches as you want. Have a read of the svk manual to see what else is possible. For example, if you’ve some patches to contribute back, you can create a new local branch, apply just those patches to it, make sure the tests pass, then svk diff to create a patch.

¹ Due to the way I have my svn setup I needed to do some other stuff to stop it trying to find the latest revision. If your deploy gets stuck in a loop trying mention it in the comments and I’ll add that code to the article.