25 May
2012
25 May
'12
3:45 p.m.
On 05/25/2012 02:16 AM, Vincent Massol wrote:
Hi devs,
Since I'm working on making XE work in Windows7 I've thought more about
XWiki's install and configuration. Actually this is not a new topic, I remember
starting a discussion about it a few years ago on the devs list but we didn't act on
it so here it comes again ;)
Rationale
========
The idea is to separate XWiki's binaries from its data. There are several reasons for
wanting this:
* Some OSes require this and don't allow writing in the binary directory. Windows 7
for example won't allow writing data in \Program Files.
* It makes upgrading simpler since you don't need to fish for configuration data and
copy them somewhere before unpacking a new distribution over. Or if you unpack in a new
directory you don't need to copy the data from the old directory to the new one.
* As a consequence of the previous point It allows easier auto upgrades of XE
* It makes it simpler to know what to backup: all you need to back is the data
directory.
Proposal
=======
This is the simplest I've found (I've imagine a lot of more complex options which
offer other small possibilities but in the end I went for the simpler one for now). So
here goes the process when starting up XE:
* XE looks for a XWIKI_DATA environment variable and if found it uses it as its
environment.permanentDirectory value
* If not found, XE looks in the user home directory for an XWiki directory. Now the name
of this directory is environment-dependent. On non windows systems it looks for
".xwiki" directory and on Windows systems it looks for a "XWiki"
directory.
* If not found, then XE stops and prints a message in the console explaining that it
couldn't find the location of the XWiki Data dir with explanations on how to set it.
The recommendation is thus that users set the XWIKI_DATA environment property.
I prefer the current way, defining it in xwiki.properties. Changing the
way this configuration works is going to add some more headache for
upgrades.
AFAIR, it is possible in the izpack installer to filter a configuration
file with values from the environment, or even asked from the user.
I don't know how many people know how to define system variables, and
even with a tutorial in front it is possible to mess it up.
Plus, on a web-managed environment, are there ways of defining
environment variables without needing restart rights on the servlet
container?
Notes:
* At startup XE prints as an INFO log the location of the permanent dir it is using.
* For the standalone distribution we would set the XWIKI_DATA env variable in the xwiki
start file (start_xwiki.sh and start_xwiki.bat) to point to the data/ dir in the
distribution.
* One aspect that is not covered here yet (the topic for another email): the installer.
I'll prepare another mail for that since it's independent for me.
Use cases
=========
This allows the following use cases:
* Make it easy to upgrade XE
* Make it easy to backup XE
* MAke it easy to use an existing XE install but point it to a different configuration,
for testing purposes for ex
* Allow installing XE for all users on a system
* Allow installing XE for my user only
WDYT?
Thanks
-Vincent
--
Sergiu Dumitriu
http://purl.org/net/sergiu/