The Update Center desktop update notifier is a small application that resides in the system tray or task bar. It monitors registered application installations and package repositories periodically to see if any updates are available for the software installed by the user. When updates are available the notifier informs the user and subsequently allows the user to review and apply the updates. You can see some of the screenshots for the notifier on the Update Center wiki.
Generally the notifier is started when a user logs into their desktop. In order for the notifier to be started when a user logs in it must first be registered as a log in start up task.
There are a couple of paths that will result in a registered notifier. For example the GlassFish v3 Prelude installer allows the user to "Enable Update Tool". By selecting this option the notifier will be registered and started as part of the GlassFish installation. Here's an example of the GlassFish Update Configuration screen:
Some products may use the Update Center's bootstrap and stub scripts as a way to minimize the download size of the product as well as maintain platform neutral distributions . When the user launches the updatetool bootstub (to install the actual Update Tool packages) it will register and start the notifier:
The software needed for this command (updatetool) is not installed.
If you choose to install Update Tool, your system will be automatically
configured to periodically check for software updates. If you would like
to configure the tool to not check for updates, you can override the
default behavior via the tool's Preferences facility.
When this tool interacts with package repositories, some system information
such as your system's IP address and operating system type and version
is sent to the repository server. For more information please see:
Once installation is complete you may re-run this command.
Would you like to install Update Tool now (y/n):
(package installation output deleted)
Registering notifier: Successful.
If the notifier was not registered during installation it can be registered post install. The Update Tool GUI application will attempt to register and start the notifier (if it is not already registered and running) shortly after it is launched if the update check frequency preference is set to a value other than "Never". You can check this preference via the Updates tab in the Update Tool Preferences dialog.
Finally the notifier can be started manually from the command line like this:
% updatetool --notifier
but only one instance of the notifier per user can be running simultaneously. So if the notifier was started as a log in start up task a second instance started manually might complain:
% updatetool --notifier
Update Tool Notifier: The tool is already running.
Is the Notifier Registered?
There is an easy way to determine if the notifier is registered as a start up task on your system. Go to the directory where you installed Update Tool or Glassfish and navigate into the updatetool/bin directory. The updatetoolconfig tool can be used to manage the notifier's registration. To see if the notifier is already registered run updatetoolconfig like this:
% updatetoolconfig --list
If this doesn't display any output then the notifier is not registered. The tool also returns an exit code of 1 if the notifier is not registered.
Registering/Unregistering the Notifier
You can also use the updatetoolconfig tool to manually register and unregister the notifier:
% updatetoolconfig --register
% updatetoolconfig --unregister
A couple of comments about these operations. If a notifier is already registered then --register will not work. To override the existing registration you can use the --register --force options.
If there are multiple installed product images that the notifier is monitoring on the system then a simple --unregister will not unregister the notifier. The notifier can only be unregistered this way if there is only one monitored image remaining (more about this in a future blog entry).
To force the notifier to be unregistered when there are more than one installed product images on the system use the --force option along with --unregister.
You can alway verify the registration or unregistration was successful by using the --list option.
Registering the notifier with the updatetoolconfig tool will not cause the notifier to be started immediately. You must log out and then log back in to trigger the start of the notifier.
Notifier Firewall Interaction
When the notifier is started it opens a port and listens for connections from the Update Tool. If this is the first time the notifier is run it may trigger your firewall to display a security alert indicating that Python (the notifier is based on Python) is attempting to connect to the network. You should allow this operation.