- Move UploadsTransfer to ProjectTransfer and inherit from this to UploadsTransfer and PagesTransfer

Revert "Store pages in shared/pages/fqdn/fqdn/public or shared/pages/fqdn/subpath/public - makes it simpler to implement CNAMEs in future"

This reverts commit 86a2a78f0d13a678899460638add6b862059433e.

Store pages in shared/pages/fqdn/fqdn/public or shared/pages/fqdn/subpath/public - makes it simpler to implement CNAMEs in future

- The pages are created when build artifacts for `pages` job are uploaded
- Pages serve the content under: http://group.pages.domain.com/project
- Pages can be used to serve the group page, special project named as host: group.pages.domain.com
- User can provide own 403 and 404 error pages by creating 403.html and 404.html in group page project
- Pages can be explicitly removed from the project by clicking Remove Pages in Project Settings
- The size of pages is limited by Application Setting: max pages size, which limits the maximum size of unpacked archive (default: 100MB)
- The public/ is extracted from artifacts and content is served as static pages
- Pages asynchronous worker use `dd` to limit the unpacked tar size
- Pages needs to be explicitly enabled and domain needs to be specified in gitlab.yml
- Pages are part of backups
- Pages notify the deployment status using Commit Status API
- Pages use a new sidekiq queue: pages
- Pages use a separate nginx config which needs to be explicitly added

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

When the trigger endpoint is called, it has to find the right service
for the given project. However, the old implementation did much more.

For example, it build a list of the missing services on this project.
This whole process took about 750ms _each time_. The current
implementation is expected to perform 10x better, as it only searches in
the current projects services. Given the service has to be configured
anyway, this can be done.

* Regenerates tokens for all models that have them
* Remove variables, since they are basically just storing encrypted data
* Bumped version up to 0.1.6
* Updated related docs

Signed-off-by: NRémy Coutable <remy@rymai.me>

This will avoid autoloading issues in the long term.
Signed-off-by: NRémy Coutable <remy@rymai.me>

Encoding.default_external was chosen over
Encoding.default_internal because File.read is
returning Encoding.default_external, therefore
we should align with it. Alternatively, we could
force both of them to be Encoding.default_internal.

However, ideally this should be determined by different
projects. For example, some projects might want to use
an encoding different to what GitLab is using.

This might not happen soon though.

Closes #27052

This reverts commit e9d8fc94.

Encoding.default_external was chosen over
Encoding.default_internal because File.read is
returning Encoding.default_external, therefore
we should align with it. Alternatively, we could
force both of them to be Encoding.default_internal.

However, ideally this should be determined by different
projects. For example, some projects might want to use
an encoding different to what GitLab is using.

This might not happen soon though.

Closes #27052

There were two cases that could be problematic:

1. Because sometimes AuthorizedProjectsWorker would be scheduled in a
   transaction it was possible for a job to run/complete before a
   COMMIT; resulting in it either producing an error, or producing no
   new data.

2. When scheduling jobs the code would not wait until completion. This
   could lead to a user creating a project and then immediately trying
   to push to it. Usually this will work fine, but given enough load it
   might take a few seconds before a user has access.

The first one is problematic, the second one is mostly just annoying
(but annoying enough to warrant a solution).

This commit changes two things to deal with this:

1. Sidekiq scheduling now takes places after a COMMIT, this is ensured
   by scheduling using Rails' after_commit hook instead of doing so in
   an arbitrary method.

2. When scheduling jobs the calling thread now waits for all jobs to
   complete.

Solution 2 requires tracking of job completions. Sidekiq provides a way
to find a job by its ID, but this involves scanning over the entire
queue; something that is very in-efficient for large queues. As such a
more efficient solution is necessary. There are two main Gems that can
do this in a more efficient manner:

* sidekiq-status
* sidekiq_status

No, this is not a joke. Both Gems do a similar thing (but slightly
different), and the only difference in their name is a dash vs an
underscore. Both Gems however provide far more than just checking if a
job has been completed, and both have their problems. sidekiq-status
does not appear to be actively maintained, with the last release being
in 2015. It also has some issues during testing as API calls are not
stubbed in any way. sidekiq_status on the other hand does not appear to
be very popular, and introduces a similar amount of code.

Because of this I opted to write a simple home grown solution. After
all, all we need is storing a job ID somewhere so we can efficiently
look it up; we don't need extra web UIs (as provided by sidekiq-status)
or complex APIs to update progress, etc.

This is where Gitlab::SidekiqStatus comes in handy. This namespace
contains some code used for tracking, removing, and looking up job IDs;
all without having to scan over an entire queue. Data is removed
explicitly, but also expires automatically just in case.

Using this API we can now schedule jobs in a fork-join like manner: we
schedule the jobs in Sidekiq, process them in parallel, then wait for
completion. By using Sidekiq we can leverage all the benefits such as
being able to scale across multiple cores and hosts, retrying failed
jobs, etc.

The one downside is that we need to make sure we can deal with
unexpected increases in job processing timings. To deal with this the
class Gitlab::JobWaiter (used for waiting for jobs to complete) will
only wait a number of seconds (30 by default). Once this timeout is
reached it will simply return.

For GitLab.com almost all AuthorizedProjectWorker jobs complete in
seconds, only very rarely do we spike to job timings of around a minute.
These in turn seem to be the result of external factors (e.g. deploys),
in which case a user is most likely not able to use the system anyway.

In short, this new solution should ensure that jobs are processed
properly and that in almost all cases a user has access to their
resources whenever they need to have access.

Signed-off-by: NRémy Coutable <remy@rymai.me>

The conflict happens when we try to update a build,
but fail to do so due to fact that we update the same build concurrently for two different runners.

See !8028 and #24833

Was proposed in #24833