We moved this file to `app/lib/` in commit cb477149c so it would be in
the autoload_paths. However, this class is loaded by ActiveStorage, with
the following method:
```
def resolve(class_name)
require "active_storage/service/#{class_name.to_s.underscore}_service"
ActiveStorage::Service.const_get(:"#{class_name.camelize}Service")
rescue LoadError
raise "Missing service adapter for #{class_name.inspect}"
end
``
So this file needs to be in the $LOAD_PATH, or else ActiveStorage won't
be able to load it when we disable the `add_autoload_paths_to_load_path`
option, which is the default in Rails 7.1 [1].
Moving it to the `lib` folder solves the issue; as mentioned in the
guide to upgrade to Rails 7.1 [2]:
> The lib directory is not affected by this flag, it is added to
> $LOAD_PATH always.
However, we were also referencing this class in the `Tenant` model,
meaning we needed to autoload it as well somehow. So, instead of
directly referencing this class, we're using `respond_to?` in the Tenant
model.
We're changing the test so it fails when the code calls
`is_a?(ActiveStorage::Service::TenantDiskService)`. We need to change
the active storage configurations in the test because, otherwise, the
moment `ActiveStorage::Blob` is loaded, the `TenantDiskService` class is
also loaded, meaning the test will pass when using `is_a?`.
Note that, since this class isn't in the autoload paths anymore, we need
to add a `require` in the tests. We could add an initializer to require
it; we're not doing it in order to be consistent with what ActiveStorage
does: it only loads the service that's going to be used in the current
Rails environment. If somebody changed their production environment in
order to use (for example), S3, and we added an initializer to require
the TenantDiskService, we would still load the TenantDiskService even if
it isn't going to be used.
[1] https://guides.rubyonrails.org/v7.1/configuring.html#config-add-autoload-paths-to-load-path
[2] https://guides.rubyonrails.org/v7.1/upgrading_ruby_on_rails.html#autoloaded-paths-are-no-longer-in-$load-path
Note we could use `acts_as_paranoid` with the `without_default_scope`
option, but we aren't doing so because it isn't possible to consider
deleted records in uniqueness validations with the paranoia gem [1].
I've added tests for these cases so we don't accidentally add
`acts_as_paranoid` in the future.
Also note we're extracting a `RowComponent` because, when
enabling/disabling a tenant, we're also enabling/disabling the link
pointing to its URL, and so we need to update the URL column after the
AJAX call.
[1] See issues 285 and 319 in https://github.com/rubysherpas/paranoia/
Some institutions using CONSUL have expressed interest in this feature
since some of their tenants might already have their own domains.
We've considered many options for the user interface to select whether
we're using a subdomain or a domain, like having two separate fields,
using a check box, ... In the end we've chosen radio buttons because
they make it easier to follow a logical sequence: first you decide
whether you're introducing a domain or subdomain, and then you enter it.
We've also considered hiding this option and assuming "if it's got a
dot, it's a domain". However, this wouldn't work with nested subdomains
and it wouldn't work with domains which are simply machine names.
Note that a group of radio buttons (or check boxes) is difficult to
style when the text of the label might expand over more than one line
(as is the case here on small screens); in this case, most solutions
result in the second line of the label appearing immediately under the
radio button, instead of being aligned with the first line of the label.
That's why I've added a container for the input+label combination.
Creating a schema takes about 3-4 seconds on my machine, so omitting
the callbacks makes tests much faster.
To do so, we're using the `insert!` method added in Rails 6.0, which
inserts a record without executing callbacks or validations. To make the
tests look consistent, we're adding a FactoryBot strategy which uses
`insert!` instead of `create!`.
Note this strategy is useless in most cases because it doesn't work when
models have translatable attributes or associations. However, IMHO it's
worth it even if we only use it for tenants.
We could also use `Tenant.insert!` instead, but then we would have to
add all the mandatory attributes, and in this case the code is clearer
if we only add the attributes we need for the test.
Right now this is configured using the `secrets.yml` file, which is the
file we've used in the past to configure SMTP settings.
Note that, in the `current_secrets` method, the `if default?` condition
is there so in single-tenant applications it returns the exact same
object as `Rails.application.secrets`, and it makes it immediately clear
for developers reading the code. We're also caching the tenant secrets
(using `||=`) so they behave the same way as Rails secrets; for this to
work properly 100% of the time (for example, in tests) we need to expire
these cached secrets whenever the Rails secrets change.
A similar `unless Tenant.default?` condition is present in the
ApplicationMailer because there's a chance some CONSUL installations
might not be using secrets to define the SMTP settings(they might be
using environment variables, for example) and so in this case we don't
want to force settings based on the secrets.yml file because it would
break the application.
The structure of the SMTP settings in the secrets file should be:
```
production:
tenants:
name_of_the_tenant_subdomain:
smtp_settings:
address:
(...)
```
Note we aren't allowing to delete a tenant because it would delete all
its data, so this action is a very dangerous one. We might need to add a
warning when creating a tenant, indicating the tenant cannot be
destroyed. We can also add an action to delete a tenant which forces the
admin to write the name of the tenant before deleting it and with a big
warning about the danger of this operation.
For now, we're letting administrators of the "main" (default) tenant to
create other tenants. However, we're only allowing to manage tenants
when the multitenancy configuration option is enabled. This way the
interface won't get in the way on single-tenant applications.
We've thought about creating a new role to manage tenants or a new URL
out of the admin area. We aren't doing so for simplicity purposes and
because we want to keep CONSUL working the same way it has for
single-tenant installations, but we might change it in the future.
There's also the fact that by default we create one user with a known
password, and if by default we create a new role and a new user to
handle tenants, the chances of people forgetting to change the password
of one of these users increases dramatically, particularly if they
aren't using multitenancy.
We had some of the logic in the ApplicationMailer. Since we're going to
use this logic in more places, we're moving it to the Tenant model,
which is the model handling everything related to hosts.
Some tasks don't have to run on every tenant. The task to calculate the
TSV is only done for records which were present before we added the TSV
column, and that isn't going to happen in any tenants because we added
the TSV column before adding the tenants table. Similarly, the migration
needed for existing polls isn't necessary because there weren't any
tenants before we allowed to set the starting/ending time to polls.
We aren't adding any tests for these tasks because tests for rake tasks
are slow and tests creating tenants are also slow, making the
combination of the two even slower, particularly if we add tests for
every single task we're changing. We're adding tests for the
`.run_on_each` method instead.
The subdomain elevator we were using, which is included in apartment,
didn't work on hosts already including a subdomain (like
demo.consul.dev, for instance). In those cases, we would manually add
the subdomain to the list of excluded subdomains. Since these subdomains
will be different for different CONSUL installations, it meant each
installation had to customize the code. Furthermore, existing
installations using subdomains would stop working.
So we're using a custom method to find the current tenant, based on the
host defined in `default_url_options`.
In order to avoid any side-effects on single-tenant applications, we're
adding a new configuration option to enable multitenancy
We're enabling two ways to handle this configuration option:
a) Change the application_custom.rb file, which is under version control
b) Change the secrets.yml file, which is not under version control
This way people prefering to handle configuration options through
version control can do so, while people who prefer handling
configuration options through te secrets.yml file can do so as well.
We're also disabling the super-annoying warnings mentioning there are no
tenants which we got every time we run migrations on single-tenant
applications. These messages will only be enabled when the multitenancy
feature is enabled too. For this reason, we're also disabling the
multitenancy feature in the development environment by default.
Note we're using the `:HOST` regular expression since subdomains can
contain the same characters as domains do. This isn't 100% precise,
though, since subdomains have a maximum length of 63 characters, but is
good enough for our purposes.
This way all tenants will be able to access them instead of just the
default one.
The apartment gem recommends using a rake task instead of a migration,
but that's a solution which is primarily meant for new installations.
Migrations are easier to execute on existing installations.
However, since this migration doesn't affect the `schema.rb` file, we
still need to make sure the shared schema is created in tasks which do
not execute migrations, like `db:schema:load` or `db:test:prepare`, just
like the apartment gem recommends. That's why we're enhancing these
tasks so they execute this migration.
Note that there might be cases where the database user isn't a superuser
(as it's usually the case on production environments), meaning commands
to create, alter or drop extensions will fail. There's also the case
where users don't have permissions to create schemas, which is needed in
order to create the shared extensions schema and the schemas used by the
tenants. For these reasons, we're minimizing the number of commands, and
so we only alter or create extensions when it is really necessary.
When users don't have permission, we aren't running the commands but
showing a warning with the steps needed to run the migration manually.
This is only necessary on installations which are going to use
multitenancy; single-tenant applications upgrading don't need to run
this migration, and that's why we aren't raising exceptions when we
can't run it.
For new installations, we'll change the CONSUL installer so extensions
are automatically created in the shared schema.
Also note the plpgsql extension is not handled here. This is a special
extension which must be installed on the pg_catalog schema, which is
always in the search path and so is shared by all tenants.
Finally, we also need to change the `database.yml` file in order to
search for shared extensions while running migrations or model tests,
since none of our enabled extensions are executed during migrations;
we're also adding a rake task for existing installations. Quoting the
apartment documentation:
> your database.yml file must mimic what you've set for your default and
> persistent schemas in Apartment. When you run migrations with Rails,
> it won't know about the extensions schema because Apartment isn't
> injected into the default connection, it's done on a per-request
> basis.
