For the record, I think that the type-based view of Demeter would definitely flag your example and call for a rewrite. Just as one example, “!version.special_case” is interacting with a type (Version) which is neither in the method’s signature nor among the class’ members. As far as I can tell.

BTW, thank you for correctly characterizing my view of AR’s role in a class. I do indeed think of AR as an external dependency posing as part of a class.

Since then I’ve seen many university trained developers write code like this.

$ passenger-install-apache2-module

instead of

$ ./passenger-install-apache2-module

I think it makes a nice addition to your tutorial.

1. Remove default mysql installation

$ rm -rf /Library/StartupItems/MySQLCOM
$ rm -rf /Library/PreferencePanes/My*
$ vim /etc/hostconfig and removed the line MYSQLCOM=-YES-
$ rm -rf ~/Library/PreferencePanes/My*
$ rm -rf /Library/Receipts/mysql*
$ rm -rf /Library/Receipts/MySQL*
$ rm -rf /var/db/receipts/com.mysql.*

Also remove all files from these locations:

/usr/bin Client programs
/var/mysql Log files, databases
/usr/libexec The mysqld server
/usr/share/man Unix manual pages
/usr/share/mysql/mysql-test MySQL test suite
/usr/share/mysql Miscellaneous support files, including error messages, character set files, sample configuration
files, SQL for database installation
/var/mysql/mysql.sock Location of the MySQL Unix socket

NOTE: Most Important
OS X Server uses launchd to start the server at boot and uses the /System/Library/ location.

You need to unload it
$ launchctl unload -w /System/Library/LaunchDaemons/org.mysql.mysqld.plist

then delete it
$ rm /System/Library/LaunchDaemons/org.mysql.mysqld.plist

—————————————————————————————————-

2. Install mysql via homebrew

$ brew install mysql

—————————————————————————————————-

3. Edit /etc/my.cnf
You need to set the socket location and the ‘tmp’ directory location (more on this in next section).

$ vim /etc/my.cnf

[client]
port = 3306
socket = /tmp/mysql.sock

[mysql.server]
user=mysql
basedir=/usr/local/var/mysql

[mysqld]
port = 3306
socket = /tmp/mysql.sock
tmpdir=/usr/local/var/mysql/tmp

—————————————————————————————————-

4. Configure mysql

a) create mysql user and groups
# create the MySQL group
dscl . create /Groups/mysql
# give it some group id
dscl . create /Groups/mysql gid 296
# create a MySQL user
dscl . -create /Users/mysql
# make the MySQL user a member of the MySQL group
dscl . append /Groups/mysql GroupMembership mysql
# change ownership to mysql
cd /usr/local/var/mysql
chown -R mysql .
chgrp -R mysql .

b) Make a tmp directory. This gets rid of the default errors you get using mysql_install_db.

$ cd /usr/local/var/mysql
$ sudo mkdir tmp
$ sudo chown mysql:mysql tmp
$ sudo chmod 777 tmp

c) install mysql tables
mysql_install_db –user=mysql

d) Create a root password
mysqladmin -u root password your_root_password

e) Test launch as root
mysqld_safe –user=root &
$ ps -e | grep mysqld # should show running server process as root
$ killall mysqld

f) Test launch as mysql
$ mysqld_safe –user=mysql &
$ ps -e | grep mysqld # should show running server as mysql
$ killall mysqld

g) Configure to launch mysql server on boot with launchd

$ cp /usr/local/Cellar/mysql/5.x.xx/com.mysql.mysqld.plist /System/Library/LaunchDaemons

$ vim /System/Library/LaunchDaemons/com.mysql.mysql.plist

change user name from ‘root’ to ‘mysql’

UserName
mysql

$ cd /System/Library/LaunchDaemons

$ launchctl unload com.mysql.mysqld.plist

$ launchctl load com.mysql.mysqld.plist

h) reboot server and test

$ sync;sync;reboot

wait for server to reboot and check server process is running as user ‘mysql’

ps -e | grep mysqld

Et Voila!

Now gem install mysql works flawlessly and you have an upgraded version of mysql on OS X Server 10.6.x

Also you don’t seem to be install the MySQL Gem.
This required a bit of work to get installed on 10.6.5 Server and the default install of MySQL is still the one running after your install.

It probably requires to just not install MySQL via brew in your step and to just use the default install and fetch the client binaries (for the installed version) and build against them.
The latest binaries (5.0.91) for 10.6.5 are available from:

http://support.apple.com/kb/HT4006

but substitute MySQL-54 instead of MySQL-49 as listed.

If you add the path to the bin, lib and include folders of the binary install, gem install mysql works.

Now, if you know a clean way to get brew to remove the default MySQL and build everything, I’m all ears

Thanks for the article – some nice bits in it!

ET