Some attachments (e.g. image_small, image_medium) are stored in DB
instead of the object storage for faster access.
In some situations, we may have pushed all these files on the Object
Storage (migration from a filesystem to object storage) and want to
bring back these attachments from the object storage to the database.
This method is not called anywhere but can be called by RPC or scripts.
Assume the following situation:
* We have installed addons base, sale and attachment_s3 (hence
base_attachment_object_storage as dependency)
* All attachments are in S3 already
* We run an upgrade of the 'base' addon, 'sale' is upgraded before
attachment_s3 in the order of loading.
* Sale updates the icon of the Sale menu
* As attachment_s3 is not loaded yet, the attachment is created in the
filestore
Now if we don't persist the filestore or use different servers, we'll
lose the images of the menus (or any attachment loaded by the
install/upgrade of an addon).
The implemented solution is to move the attachments from the filestore
to the object storage at the loading of the module. However, this
operation can take time and it shouldn't be run by 2 processes at the
same time, so we want to detect if the module is loaded during a normal odoo
startup or when some addons have been upgraded. There is nothing anymore
at this point which allow us to know that modules just have been
upgraded except... in the caller frame (load_modules). We have to rely
on the inpect module and get the caller frame, which is not recommended,
but seems the only way, besides, it's not called often and if
_register_hook was called from another place, it would have no effect
(unless the other place has a variable 'update_module' too).
When moving attachments from the filestore to an object storage, the
filesystem files will be deleted only after the commit, so if the
transaction is rollbacked, we still have the local files for another
try.
Guewen Baconnierandsebalix
Akim Juillerat
jcoux
Thierry DucrestandGuewen Baconnier