The generation inside the rendering has some drawbacks:
- `commit_assetsbundle` is needed for reports rendering because the
template rendering may generate some assets that will be accessed by
another transaction before the transaction is committed. But this
solution is not ideal since the transaction is committed in the middle
of the request
- when the first rendered page is a 404, the assets are not committed
and the page is broken.
- when starting, deleting an attachment can create a concurrent update
error and the request is retried. This will occur once per attachment
and for all worker trying to access the same resource. The whole
transaction is rollbacked, even the previously created assets bundle.
- The cold page load is a slower since there is more work to do.
- Implementing a readonly request is difficult because it could be
transformed to read write and re-executed if the assets bundle does not
exist.
Generating assets when needed solves those issues. The concurrency
when deleting an assets could still occur but only once per bundle, and
in a smaller transaction. This could be solved with a lock now that we
have more control on the transaction. The commit_assetsbundle can be
removed and 404 page should have a correct layout. The cold page load
could be a little faster because the assets bundle can be generated in
parallel requests instead of sequentially when rendering the page.
Part-of: odoo/odoo#131353
Xavier-Do
64bbef5bc1
