"""
Abstract base class for queue execution strategies.
"""
from abc import ABC, abstractmethod
from typing import Any, Dict, Optional
class QueueStrategy(ABC):
"""
Abstract base class for queue execution strategies.
Different Fal client patterns require different approaches to queue operations:
- subscribe_async(): Event streaming, used in stdio transport
- submit_async() + polling: Manual status checks, used in HTTP transport
- submit_async() + handle.get(): Simple blocking, used in dual transport
Each strategy encapsulates one of these patterns.
"""
@abstractmethod
async def execute(
self,
model_id: str,
arguments: Dict[str, Any],
timeout: int = 300,
) -> Optional[Dict[str, Any]]:
"""
Execute a long-running operation via the Fal queue.
Args:
model_id: The Fal.ai model endpoint to call
arguments: Arguments to pass to the model
timeout: Maximum time to wait for completion (seconds)
Returns:
The result dictionary from the model, or None if timeout/error
Raises:
asyncio.TimeoutError: If the operation times out
Exception: If the operation fails
"""
pass
@abstractmethod
async def execute_fast(
self,
model_id: str,
arguments: Dict[str, Any],
) -> Dict[str, Any]:
"""
Execute a fast operation directly (no queue).
Used for operations that complete quickly (e.g., image generation)
and don't need queue management.
Args:
model_id: The Fal.ai model endpoint to call
arguments: Arguments to pass to the model
Returns:
The result dictionary from the model
Raises:
Exception: If the operation fails
"""
pass
