I wrote a little CDN server that rebuilds its registry pool when new pool-content-packages are installed into that registry pool.
Instead of having each pool-content-package call the init.d of the cdn-server, I'd like to use triggers. That way it would restart the server only once at the end of an installation run, after all packages were installed.
What have I to do to use triggers in my packages with debhelper support?
What you are looking for is dpkg-triggers.
One solution with use of debhelper to build the debian packages is this:
Step 1)
Create file debian/<serverPackageName>.triggers (replace <serverPackageName> with name of your server package).
Step 1a)
Define a trigger that watch the directory of your pool. The content of file would be:
interest /path/to/my/pool
Step 1b)
But you can also define a named trigger, which have to be fired explicit (see step 3).
content of file:
interest cdn-pool-changed
The name of the trigger cdn-pool-changed is free. You can take what ever you want.
Step 2)
Add handler for trigger to file debian/<serverPackageName>.postinst (replace <serverPackageName> with name of your server package).
Example:
#!/bin/sh
set -e
case "$1" in
configure)
;;
triggered)
#here is the handler
/etc/init.d/<serverPackageName> restart
;;
abort-upgrade|abort-remove|abort-deconfigure)
;;
*)
echo "postinst called with unknown argument \`$1'" >&2
exit 1
;;
esac
#DEBHELPER#
exit 0
Replace <serverPackageName> with name of your server package.
Step 3) (only for named triggers, step 1b) )
Add in every content package the file debian/<contentPackageName>.triggers (replace <contentPackageName> with names of your content packages).
content of file:
activate cdn-pool-changed
Use same name for trigger you defined in step 1.
The best description for dpkg-triggers I could found is "How to use dpkg triggers". The corresponding git repository with examples you can get here:
git clone git://anonscm.debian.org/users/seanius/dpkg-triggers-example.git