hg = git >> svnThat settled it. I had to pick one, and move forward. I chose mercurial, not because it stood out above git, but it seemed to be more widely adopted in the communities I was interested in. Joel Spolsky's mercurial primer settled it for me. Mercurial was on it's way in. I had identified identified some key obstacles I needed to overcome to replace my subversion infrastructure with a new mercurial one. I had to figure out:
- How to install hg in CENTOS 5
- How to import the revision history from svn into hg
- How to get LDAP authentication to work with hg
- How to integrate hg with hudson (our continuous integration server)
- How to get the maven release plugin to work with hg
1) Install mercurial in CENTOS 5
I hunted around for a while looking for an RPM, but found nothing recent. On a twitter recommendation, I tried installing from source. Turned out to be pretty easy. The install ended up putting mercurial in my /usr/local/lib64 directory, which is not one of the default places python looks for it's modules. I had to do set the PYTHONPATH environment variable pointing to this directory to get things to work.2) svn import into hg
Turns out mercurial has this functionality built in with the bundled Convert Extension. One has to enable this extension in a mercurial configuration file, then it's pretty simple to point the "hg convert" command at your subersion repo. Done and done!3) LDAP integration
I'd achieved svn LDAP integration using apache, so I was quite happy to see hg did the same thing. I set up the hgwebdir.cgi script to serve my newly imported hg repositories, hi-jacking the LDAP authentication from my svn setup. Worked like a charm.Update, here's the apache config for authentication:
# cat /etc/httpd/conf.d/hg.conf ScriptAlias /hg "/var/www/hg/hgwebdir.cgi"Note: the group terms are specific to the IBM Tivoli LDAP server.Order deny,allow Deny from all Allow from 10.0.0.1 AuthType Basic AuthBasicProvider ldap AuthName "LDAP password" AuthLDAPURL "ldaps://ldap.domain.com/ou=users,dc=domain,dc=ccom?uid?sub?(&(uniqueidentifier=*)(objectclass=eperson))" AuthLDAPGroupAttribute ibm-allmembers require ldap-group cn=mis,ou=web,ou=Groups,dc=domain,dc=com Satisfy Any
4) hg integration with Hudson
This one seemed simple enough, given that there is a mercurial plugin for hudson. It was simple enough to install, but took a bit of effort to get going. I had to go into the hudson configuration, and define a mercurial "instance" pointing to a wrapper that set the PYTHONPATH environment variable, then delegated the argument to mercurial itself. Again, I think this is due to the /usr/local/lib64 path the mercurial installer chose. Maybe this could be done more cleanly, but it's working now.Another hiccup with the hudson configuration, was that there was no place to put a username and password, as one did with the svn/hudson config. I worked around this by adding the IP of my hudson server to the "allow from" section of my apache config file. Thus hudson could pull from my hg repos without authenticating.
A few hurdles with this one, but nothing severe.
Update (in answer to a comment):
My hg warpper looks like:
# cat /usr/local/bin/hg_pythonpath_wrapper #!/bin/sh export PYTHONPATH=/usr/local/lib64/python2.4/site-packages /usr/local/bin/hg "$@"
To get hudson to use this wrapper, goto: Manage Hudson -> Configure System Scroll down to the mercurial section, click the "Add Mercurial" plugin, and point the executable to the above wrapper.
