In the first recipe, we saw how to install Odoo from source using the git repository. The main benefit of this setting is being able to update the source code of Odoo using git to get the latest bug fixes.

Stop any instance that's currently running with the Odoo source you are about to update, and then make a backup of all of the databases you care about in case something goes wrong. This is obviously something you need to do for production databases. Refer to the Managing Odoo server databases recipe of this chapter for further instructions.

Next, make a note of the current version of the source you are running. The best way to do this is by creating a lightweight tag using the following command:

$ cd ~/odoo-dev/odoo
$ git checkout 12.0
$ git tag 12.0-before-update-$(date --iso)

To update the source code of Odoo, use the following command:

$ git pull –-ff-only origin 12.0

This will fetch the latest version of the source code that's committed to the current branch.

To update an instance running on this code, run the following command:

$ ./odoo-bin -c myodoo.cfg --stop-after-init -u base

If you don't have a database set in the configuration file, you will have to add the
-d database_name option. This command is to be repeated for all of the instances that are running with this version of the source code.

If the update fails, don't panic, because you have backups:

1. Read the error message carefully and save it to a file, as it will be useful for making a bug report later.
2. If you cannot figure out what the problem is, restore the service and the Odoo source code to the previous version, which is known to work using the tag you set before updating the source version:

$ git reset --hard 12.0-before-update-$(date --iso)

3. Drop the broken databases and restore them from the backups you made (refer to the Managing Odoo server databases recipe of this chapter for instructions).
4. Restart your instances and tell your users that the upgrade has been postponed.

Updating the source code is done by ensuring that we are on the correct branch using git checkout and then fetching the new revisions using git pull. The --ff-only option will cause a failure if you have local commits that aren't present in the remote repository. If this happens and you want to keep your changes, you can use git pull (without --ff-only) to merge the remote changes with yours. If not, use git reset --hard origin/12.0 to force the update, hence discarding your local modifications.

The update command uses the following options:

• -c: Specifies the configuration file
• --stop-after-init: Stops the instance when the update is over
• -u base or --update base: Requests the update of the base module

When updating a module, Odoo does the following:

• It updates the database structure for the models defined in the module for which the structure changes. For updates on the stable branch of Odoo, there should be no such changes, but this can happen for your own add-ons or third-party add-ons.
• It updates the database records that are stored in data files of the module, most notably, the views. It then recursively updates the installed modules that have declared a dependency on the module.

Since the base module is an implicit dependency of all Odoo modules, updating it will trigger an update of all of the installed modules in your instance. To update all installed modules, the all alias can be used instead of base.