Retrying a queue item means cloning it, resetting all execution-related state. Retried queue items reference the item they were retried from by id. This relationship is not enforced by any DB constraints.
- Add `retried_from_item_id` to `session_queue` table in DB in a migration.
- Add `retry_items_by_id` method to session queue service. Accepts a list of queue item IDs and clones them (minus execution state). Returns a list of retried items. Items that are not in a canceled or failed state are skipped.
- Add `retry_items_by_id` HTTP endpoint that maps 1-to-1 to the queue service method.
- Add `queue_items_retried` event, which includes the list of retried items.
This is required to fix an issue with the MM UI's error handling.
Previously, we only included the model source as a string. That could be an arbitrary URL, file path or HF repo id, but the frontend has no parsing logic to differentiate between these different model sources.
Without access to the type of model source, it is difficult to determine how the user should proceed. For example, if it's HF URL with an HTTP unauthorized error, we should direct the user to log in to HF. But if it's a civitai URL with the same error, we should not direct the user to HF.
There are a variety of related edge cases.
With this change, the full `ModelSource` object is included in each model install event, including error events.
I had to fix some circular import issues, hence the import changes to files other than `events_common.py`.
The frontend needs to know where queue items came from (i.e. which tab), and where results are going to (i.e. send images to gallery or canvas). The `origin` column is not quite enough to represent this cleanly.
A `destination` column provides the frontend what it needs to handle incoming generations.
The origin is an optional field indicating the queue item's origin. For example, "canvas" when the queue item originated from the canvas or "workflows" when the queue item originated from the workflows tab. If omitted, we assume the queue item originated from the API directly.
- Add migration to add the nullable column to the `session_queue` table.
- Update relevant event payloads with the new field.
- Add `cancel_by_origin` method to `session_queue` service and corresponding route. This is required for the canvas to bail out early when staging images.
- Add `origin` to both `SessionQueueItem` and `Batch` - it needs to be provided initially via the batch and then passed onto the queue item.
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Around the time we (I) implemented pydantic events, I noticed a short pause between progress images every 4 or 5 steps when generating with SDXL. It didn't happen with SD1.5, but I did notice that with SD1.5, we'd get 4 or 5 progress events simultaneously. I'd expect one event every ~25ms, matching my it/s with SD1.5. Mysterious!
Digging in, I found an issue is related to our use of a synchronous queue for events. When the event queue is empty, we must call `asyncio.sleep` before checking again. We were sleeping for 100ms.
Said another way, every time we clear the event queue, we have to wait 100ms before another event can be dispatched, even if it is put on the queue immediately after we start waiting. In practice, this means our events get buffered into batches, dispatched once every 100ms.
This explains why I was getting batches of 4 or 5 SD1.5 progress events at once, but not the intermittent SDXL delay.
But this 100ms wait has another effect when the events are put on the queue in intervals that don't perfectly line up with the 100ms wait. This is most noticeable when the time between events is >100ms, and can add up to 100ms delay before the event is dispatched.
For example, say the queue is empty and we start a 100ms wait. Then, immediately after - like 0.01ms later - we push an event on to the queue. We still need to wait another 99.9ms before that event will be dispatched. That's the SDXL delay.
The easy fix is to reduce the sleep to something like 0.01 seconds, but this feels kinda dirty. Can't we just wait on the queue and dispatch every event immediately? Not with the normal synchronous queue - but we can with `asyncio.Queue`.
I switched the events queue to use `asyncio.Queue` (as seen in this commit), which lets us asynchronous wait on the queue in a loop.
Unfortunately, I ran into another issue - events now felt like their timing was inconsistent, but in a different way than with the 100ms sleep. The time between pushing events on the queue and dispatching them was not consistently ~0ms as I'd expect - it was highly variable from ~0ms up to ~100ms.
This is resolved by passing the asyncio loop directly into the events service and using its methods to create the task and interact with the queue. I don't fully understand why this resolved the issue, because either way we are interacting with the same event loop (as shown by `asyncio.get_running_loop()`). I suppose there's some scheduling magic happening.
Previously, we used `model_install_download_progress` for both download starting and progressing. When handling this event, we don't know which actual thing it represents.
Add `model_install_download_started` event to explicitly represent a model download started event.
Some tech debt related to dynamic pydantic schemas for invocations became problematic. Including the invocations and results in the event schemas was breaking pydantic's handling of ref schemas. I don't really understand why - I think it's a pydantic bug in a remote edge case that we are hitting.
After many failed attempts I landed on this implementation, which is actually much tidier than what was in there before.
- Create pydantic-enabled types for `AnyInvocation` and `AnyInvocationOutput` and use these in place of the janky dynamic unions. Actually, they are kinda the same, but better encapsulated. Use these in `Graph`, `GraphExecutionState`, `InvocationEventBase` and `InvocationCompleteEvent`.
- Revise the custom openapi function to work with the new models.
- Split out the custom openapi function to a separate file. Add a `post_transform` callback so consumers can customize the output schema.
- Update makefile scripts.
This is required to get these event fields to deserialize correctly. If omitted, pydantic uses `BaseInvocation`/`BaseInvocationOutput`, which is not correct.
This is similar to the workaround in the `Graph` and `GraphExecutionState` classes where we need to fanagle pydantic with manual validation handling.
There's no longer any need for session-scoped events now that we have the session queue. Session started/completed/canceled map 1-to-1 to queue item status events, but queue item status events also have an event for failed state.
We can simplify queue and processor handling substantially by removing session events and instead using queue item events.
- Remove the session-scoped events entirely.
- Remove all event handling from session queue. The processor still needs to respond to some events from the queue: `QueueClearedEvent`, `BatchEnqueuedEvent` and `QueueItemStatusChangedEvent`.
- Pass an `is_canceled` callback to the invocation context instead of the cancel event
- Update processor logic to ensure the local instance of the current queue item is synced with the instance in the database. This prevents race conditions and ensures lifecycle callback do not get stale callbacks.
- Update docstrings and comments
- Add `complete_queue_item` method to session queue service as an explicit way to mark a queue item as successfully completed. Previously, the queue listened for session complete events to do this.
Closes#6442
- Restore calculation of step percentage but in the backend instead of client
- Simplify signatures for denoise progress event callbacks
- Clean up `step_callback.py` (types, do not recreate constant matrix on every step, formatting)
We don't need to use the payload schema registry. All our events are dispatched as pydantic models, which are already validated on instantiation.
We do want to add all events to the OpenAPI schema, and we referred to the payload schema registry for this. To get all events, add a simple helper to EventBase. This is functionally identical to using the schema registry.
- Remove ABCs, they do not work well with pydantic
- Remove the event type classvar - unused
- Remove clever logic to require an event name - we already get validation for this during schema registration.
- Rename event bases to all end in "Base"
Our events handling and implementation has a couple pain points:
- Adding or removing data from event payloads requires changes wherever the events are dispatched from.
- We have no type safety for events and need to rely on string matching and dict access when interacting with events.
- Frontend types for socket events must be manually typed. This has caused several bugs.
`fastapi-events` has a neat feature where you can create a pydantic model as an event payload, give it an `__event_name__` attr, and then dispatch the model directly.
This allows us to eliminate a layer of indirection and some unpleasant complexity:
- Event handler callbacks get type hints for their event payloads, and can use `isinstance` on them if needed.
- Event payload construction is now the responsibility of the event itself (a pydantic model), not the service. Every event model has a `build` class method, encapsulating this logic. The build methods are provided as few args as possible. For example, `InvocationStartedEvent.build()` gets the invocation instance and queue item, and can choose the data it wants to include in the event payload.
- Frontend event types may be autogenerated from the OpenAPI schema. We use the payload registry feature of `fastapi-events` to collect all payload models into one place, making it trivial to keep our schema and frontend types in sync.
This commit moves the backend over to this improved event handling setup.
