Self As Team

Developing projects using ant is pretty easy and straight forward. One convention I like to follow is to organize each component in the system to have its own local build file. These builds can be aggregated by higher level builds very simply. This gives great flexibility while developing since you can build only what you need while working on it and yet you (or continuous integration) can easily perform a full build/test. If you have lots of similar components, your ant scripts might begin to have lots of duplication in them unless you start refactoring the common pieces into includes. In the old days (prior to ant 1.6), there wasn’t an obvious way to include fragements. While reviewing some open source projects back in 1995 I stumbled across the xml include technique (below) that I’ve used a few times. I had forgotten about this until I was recently asked to make some recommendations on an older project’s build approach.
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I while back needed to add an audit trail to an older project. I found the acts as audited plugin and put it into play and it is great. I added my models to it and added a way to review the audit trail online – all good – until…

I started added audits for my model associations. This went well until I wanted to audit a has and belongs to many (HABTM) association which as you know, doesn’t have to have a backing model (it simply relies on a join table that is named a particular way). Sigh. On a few HABTM as sociations, I actually had a model but our smarted myself (and followed an older web recipe) and created the model without id’s.  These associations do not work with this plugin.

No way to get there from here exept to convert HABTM to has many through. Further evidence why HABTM is shortcut that only leads to pain later if you need to extend the associations (like adding audit trails).

Avoid HABTM and your life will be better…. just imagine having to convert 10 or more association tables to models on a production system that has 1000’s of parent objects. You see any fun in that? The superstitious would call how HABTM handles join objects as ‘magic’ which isn’t really very accurate. It is simply a conventional shortcut. My big problem with it is the lack of flexibility it gives you – it is one of those box-canyon paradigms that is hard to get out of.

Oh and another note, if you add acts_as_audited to your project late in the game, you may run into problems with migrations if any migrations load data. The reason is a fresh checkout will bring the audit code which will perform audits even on migrated data and since early migrations don’t have the audit table loaded yet (it is a later migration), you can’t migrate data. Sure you can just do a rake db:schema:load but that will leave you without some of your migration data.

An easy solution is to simply rename the acts as audited migration to be your first migration (mung the date in the file name). This tricks the migration to run first and all should be fine… Note, this even works if you have previously migrated and then do an update to get this new ‘old’ migration – the migration still runs even though it is out of sequence thanks to the schema_migrations table which keeps up with what migrations have been run.

It is such a joy to have such great technologies at our fingertips. Ruby on Rails can be a fantastic productivity booster for projects but I often find I get huge benefits from it for simply exploring ideas or working up a quick functional prototype. By adding on things like customized generators that suit your client’s configuration and customizable menus, you can get to a workable prototype in record time (minutes to hours).

Part of the benefit of working with rails projects is the speed with which you can refactor and scaffold your way into different configurations. This can sometimes get you into trouble if an experiment or plugin doesn’t work. The best solution I’ve found for this is to ALWAYS initialized your fresh rails project into a git repository. This is like having infinite idea or skill mulligan’s for your project – a great safety net that let’s you go fast without fear.

Ryan Bates’s excellent screen cast series had a nice review of using git with rails and one of the commenters (Pete Yandell) offered a script to simplify life. This script sets up a standard rails project into git with the proper ignores. I modified the original script slightly to avoid placing .gitignore files into the empty directories within the .git directory. This is a harmless change but it seems cleaner to me. Here is my version of it:


#!/bin/sh
cat < .gitignore
log/*.log
tmp/**/*
db/*.sqlite3
coverage
doc/app/*
EOF
find . -type d -empty -exec touch {}/.gitignore \;
git init
echo "TODO - provide project README" > README
git add .
git commit -a -m "Initial import."

(here’s the gist)

This script works great (on OS X anyway) for setting up a project in git. This allows me to extend the ‘prototype’ from hours to multiple days if I need to without losing control or risking breaking the whole thing with a laps of concentration. I can create branches for experimental ideas and quickly switch back and forth. As long as my migrations are current and especially if I’m using data generators like populator, I can switch between branches to show my client a few different ideas or behaviors within seconds.

It is so great to have a (revisable) history of what I’ve done on a project. I can also quickly stash an idea away to work on it later. No matter what I do on the prototype, I can always recover back to some previous spot without much fuss or concern.

This technique works so well because it is all self contained within your rails directory and because it is such a low-overhead and fast approach.

The approach works like this:

1. rails some_new_project
2. cd some_new_project
3. git-rails
4. work on project for minutes or weeks with frequent checkins
5. create branches, rebase, squash commits, what ever – repeat previous steps
6. if want to keep it, move it to a public repo, if not simply rm -rf the entire directory…

Rails and git are really two powerful tools that have greatly revolutionized my personal work flow. I get to move quickly and with the assurance that I can undo any bad ideas. Infinite idea mulligans. I also get to practice using git even if my client is stuck on subversion (or worse). I highly recommend ALWAYS setting up your rails projects this way.