In order to migrate existing files from Paperclip to ActiveStorage, we
need Paperclip to find out the files associated to existing database
records. So we can't simply replace Paperclip with ActiveStorage.
That's why it's usually recommended [1] to first run the migration and
then replace Paperclip with ActiveStorage using two consecutive
deployments.
However, in our case we can't rely on two consecutive deployments
because we have to make an easy process so existing CONSUL installations
don't run into any issues. We can't just release version 1.4.0 and 1.5.0
and day and ask everyone to upgrade twice on the same day.
Instead, we're following a different plan:
* We're going to provide a Rake task (which will require Paperclip) to
migrate existing files
* We still use Paperclip to generate link and image tags
* New files are handled using both Paperclip and ActiveStorage; that
way, when we make the switch, we won't have to migrate them, and in
the meantime they'll be accessible thanks to Paperclip
* After we make the switch, we'll update the `name` column in the active
storage attachments tables in order to remove the `storage_` prefix
Regarding our handling of new files, the exception are cached
attachments. Since those attachments are temporary files used while
submitting a form and we have to delete them afterwards, we're only
handling them with Paperclip. We'll handle these ones in version 1.5.0.
Note the task creating the dev seeds was failing after these changes
with an `ActiveStorage::IntegrityError` exception because we were
opening some files without closing them. If the same file was attached
twice, it failed the second time.
We're solving it by closing the files with `File.open` and a block. Even
though we didn't get any errors, we're doing the same thing in the
`Attachable` concern because it's a good practice to close files after
we're done with them.
Also note we have to change the CKEditor Active Storage code so it's
compatible with Paperclip. In this case, I haven't been able to write a
test to confirm the attachment exists; I was getting the same
`ActiveStorage::IntegrityError` mentioned above.
Finally, we're updating the site customization image controller to use
`update` so the image and the attachment are updated within the same
transaction. This is also what we do in most controllers.
[1] https://www.youtube.com/watch?v=tZ_WNUytO9o
We were very inconsistent regarding these rules.
Personally I prefer no empty lines around blocks, clases, etc... as
recommended by the Ruby style guide [1], and they're the default values
in rubocop, so those are the settings I'm applying.
The exception is the `private` access modifier, since we were leaving
empty lines around it most of the time. That's the default rubocop rule
as well. Personally I don't have a strong preference about this one.
[1] https://rubystyle.guide/#empty-lines-around-bodies
In the scenario where we want to test scopes and use `match_array`, we
usually declare variables we never use, which raises a warning in the
Ruby interpreter (since the main cause for an unused variable is a
typo).
So I've decided to just split the tests into cases where every record is
returned and cases were no records are returned, just like we do in
other places.
There are several other options we've considered:
1. Don't declare unused variables, but declare the ones we use
2. Prefix unused variables with un underscore
3. Declare just one variable being an array containing all elements, and
access the elements using Array#[]
4. Don't declare any variables, and compare results against attributes
such as titles
None of these options was met with enthusiasm.
