Add a "Last Rendered" view to the webapp.
The Manager now stores (in the database) which job was the last
recipient of a rendered image, and serves that to the appropriate
OpenAPI endpoint.
A new SocketIO subscription + accompanying room makes it possible for
the web interface to receive all rendered images (if they survive the
queue, which discards images when it gets too full).
When a job or task gets requeued from the web interface, its task
failure lists (i.e. the list of workers that previously failed this
task) will be cleared.
This clearing doesn't happen in other situations, e.g. when a worker
signs off and its task gets requeued, the task's failure list will
remain as-is.
The persistence layer can now store which worker failed which task, as
preparation for a blocklisting system. Such a system should be able to
determine whether there are still any workers left to do the work.
This is needed for a future unit test, and exposed the fact that SQLite
didn't enforce foreign key constraints (and thus also didn't handle
on-delete-cascade attributes). This has been fixed in the previous commit.
When creating tasks the inter-task dependencies are saved as a 2nd pass,by
updating the tasks in the database. This now only saves those dependencies,
and no longer saves the entire task again.
`persistence.Model` contains the common database fields for most model
structs. It is a copy of `gorm.Model`, but without the `DeletedAt`
field (which triggers Gorm's soft deletion).
Soft deletion is not used by Flamenco. If it ever becomes necessary to
support soft-deletion, see https://gorm.io/docs/delete.html#Soft-Delete
Update the 'last seen at' timestamp of workers when they:
- sign on
- sign off
- get a task assigned
- send a task update
- check whether they can keep running their task
Note that this commit is necessary to not have the workers time out
immediately ;-)
SQLite doesn't handle timezones by default, when you just use something
like `date1 < date2`, for example. This makes GORM explicitly use UTC
timestamps for the `CreatedAt`, `UpdatedAt`, and `DeletedAt` fields.
Our own code should also use UTC when saving timestamps. That way all
datetimes in the database are in the same timezone, and can be compared
naievely.
Tasks that are in state `active` but haven't been 'touched' by a Worker
for 10 minutes or longer will transition to state `failed`.
In the future, it might be better to move the decision about which state
is suitable to the Task State Machine service, so that it can be smarter
and take the history of the task into account. Going to `soft-failed`
first might be a nice touch.
Add a small wrapper around github.com/google/uuid. That way it's clearer
which functionality is used by Flamenco, doesn't link most of the code to
any specific UUID library, and allows a bit of customisation.
The only customisation now is that Flamenco is a bit stricter in the
formats it accepts; only the `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx` is
accepted. This makes things a little bit stricter, with the advantage
that we don't need to do any normalisation of received UUID strings.
Send & handle `JobUpdate.refresh_tasks = true` when many tasks are
updated simultaneously. This applies to things like cancelling &
requeueing an entire job.
This partially rolls back 67bf77de13d99b1bc5d7344951068822c4fadd88, as
it was too slow when 1000+ tasks were being updated all at once.
Improve how the task scheduler deals with tasks that already have a
worker assigned to them:
- When a Worker asks for a task, and there is already an active task
assigned to it, always return that task.
- Otherwise, never allow scheduling of active tasks, as those are
already being run by another worker. If this is not the case, their
status should change to queued/failed, instead of handling the
situation in the task scheduler.
- Apart from the assigned-and-active case above, ignore task's worker ID
when scheduling tasks. If the status is 'queued' or 'soft-failed', the
task's worker ID just indicates who ran the task last.
Check for jobs in 'cancel-requested' or 'requeued' statuses, and ensure
they transition to the right status. This happens at startup, before
even starting the web interface, so that a consistent state is presented.
When the job status changes, it impacts the task statuses as well. These
status changes are now no longer done with a single database query, but
instead each affected task is fetched, changed, and saved. This unifies
the regular & mass updates to the tasks, and causes the resulting task
changes to be broadcast to SocketIO clients.
Add `fetchJobTasks` operation to the Jobs API. This returns a summary of
each of the job's tasks, suitable for display in a task list view.
The actually used fields may need tweaking once we actually have a task
list view, but at least the functionality is there.
To prepare for job status changes being requestable from the API, store
the reason for any status change on the job itself.
Not yet part of the API, just on the persistence layer.
Avoid users of the persistence layer to have to test against Gorm errors,
by wrapping job/task errors in a new `PersistenceError` struct.
Instead of testing for `gorm.ErrRecordNotFound`, code can now test for
`persistence.ErrJobNotFound` or `persistence.ErrTaskNotFound`.
SQLite can return `SQLITE_BUSY` errors when it's doing too many things at
the same time. This is now improved a bit by setting a 5-second timeout,
during which the SQLite driver will wait for the database to become
available. If that doesn't happen, Flamenco Manager will return a
`503 Service Unavailable` response so that the client knows to back off
a little.
