Documentation of the functionality that update-notifier currently provides and ways in which update-notifier can stop being a long running process.  Moving away from a long running process will help with the goal of [[UbuntuSpec:desktop-r-reduced-power-ram|reducing the desktop footprint]]

= File Watches =

== Reboot file ==

Watches for '''/var/run/reboot-required''' and notifies you if a reboot is required.

Monitoring could be replaced by an upstart-file-bridge.

== New package hook ==

Watches for a new file in '''/var/lib/update-notifier/user.d''' and then executes the hook there.

Monitoring could be replaced by an upstart-file-bridge and still use update-notifier to execute the hook.

== New crash report ==

Watches for a new crash report in '''/var/crash/''' and then launches '''/usr/share/apport/apport-gtk'''.

Monitoring could be replaced by an upstart-file-bridge and the job would directly call apport-gtk.

== Avahi being disabled ==

Watches for the existence of the file '''/var/run/avahi-daemon/disabled-for-unicast-local''' and then presents a notification regarding avahi having been disabled.

Monitoring could be replaced by an upstart-file-bridge and still use update-notifier to display the notification.

= Other Notifications =

== New release of Ubuntu ==

update-notifier includes a release checking system that checks, every two weeks, to see if there is a new release of Ubuntu by calling '''/usr/lib/ubuntu-release-upgrader/check-new-release-gtk'''.  If there is a new release ''check-new-release-gtk'' will present you with a dialog stating "A new version of Ubuntu is available.  Would you like to upgrade?".

There is some redundancy here in that '''/etc/update-motd.d/91-release-upgrade''' also checks for a new release of Ubuntu, however this is only run when a user gets a terminal log in.  A new weekly cron job could be created that would call '''/usr/lib/ubuntu-release-upgrader/release-upgrade-motd''' which would update '''/var/lib/update-notifier/release-upgrade-available'''.  Then an upstart job, run on desktop-session-start, would check if '''release-upgrade-available''' exists and if so start '''check-new-release-gtk''' or '''do-release-upgrade'''.

== Disk with packages on it ==

=== What happens now ===

Mounted drives are checked to see if they contain one of the following directories, '/ubuntu', '/cdromupgrade', '/aptoncd.info'.  In the event that it does a secondary check is made using '''/usr/lib/update-notifier/apt-cdrom-check'''.  Depending on the outcome of that check one of the following happens:

A dialog regarding a volume with software packages being detected is presented and '''/usr/lib/update-notifier/backend_helper.py''' is called which then launches synaptic (software-center is a fallback option) with the --add-cdrom switch.

A dialog is presented regarding upgrading from the CD and '''/usr/lib/update-notifier/cddistupgrader''' is run, which will then run the release-upgrader from the disk.

A dialog is presented regarding a volume with "addon" software applications being detected.  Depending on the response either '''/usr/lib/update-notifier/backend_helper.py''' is called or '''gnome-app-install --addon-cd''' with the mount point is. 

=== Actions ===

Remove support for "addon" CDs. - done in r755

== Hardware that requires firmware ==

=== What happens now ===

update-notifier watches for devices to be connected via USB.  If the vendor id matches 03f0 and the product id is ??{17,2a} then '''/usr/bin/hp-mkuri -c''' is called to see if firmware is required.  If it is then '''/usr/bin/hp-plugin-ubuntu''' is called.

If update-notifier is built with system-config-printer support then, if the device connected is a printer then update-notifier checks to see if system-config-printer is already running.  If it is not then '''system-config-printer-applet''' is launched. 

=== Action ===

The watching for specific devices should be done by an upstart job that should probably be shipped with hplip and not update-notifier.