refactor!: RequestQueue and service management rehaul (#429)

- closes #423
- closes #174
- closes #203
- related to #354 - let's investigate this, but I believe that it won't
go away until #433 is resolved
- closes #83 

Locking in memory storage was not implemented - see #433

---------

Co-authored-by: Vlada Dusek <v.dusek96@gmail.com>

src/crawlee/_utils/lru_cache.py

@@ -8,7 +8,7 @@
 T = TypeVar('T')
 
 
-class LRUCache(MutableMapping, Generic[T]):
+class LRUCache(MutableMapping[str, T], Generic[T]):
     """Attempt to reimplement LRUCache from `@apify/datastructures` using `OrderedDict`."""
 
     def __init__(self, max_length: int) -> None:

src/crawlee/base_storage_client/base_request_queue_client.py

@@ -11,7 +11,6 @@
         ProcessedRequest,
         ProlongRequestLockResponse,
         Request,
-        RequestListResponse,
         RequestQueueHead,
         RequestQueueHeadWithLocks,
         RequestQueueMetadata,
@@ -185,17 +184,3 @@ async def batch_delete_requests(self, requests: list[Request]) -> BatchRequestsO
         Args:
             requests: The requests to delete from the queue.
         """
-
-    @abstractmethod
-    async def list_requests(
-        self,
-        *,
-        limit: int | None = None,
-        exclusive_start_id: str | None = None,
-    ) -> RequestListResponse:
-        """List requests from the queue.
-
-        Args:
-            limit: How many requests to retrieve.
-            exclusive_start_id: All requests up to this one (including) are skipped from the result.
-        """

src/crawlee/basic_crawler/basic_crawler.py

@@ -18,15 +18,14 @@
 from tldextract import TLDExtract
 from typing_extensions import NotRequired, TypedDict, TypeVar, Unpack, assert_never
 
-from crawlee import Glob
+from crawlee import Glob, service_container
 from crawlee._utils.urls import convert_to_absolute_url, is_url_absolute
 from crawlee._utils.wait import wait_for
 from crawlee.autoscaling import AutoscaledPool, ConcurrencySettings
 from crawlee.autoscaling.snapshotter import Snapshotter
 from crawlee.autoscaling.system_status import SystemStatus
 from crawlee.basic_crawler.context_pipeline import ContextPipeline
 from crawlee.basic_crawler.router import Router
-from crawlee.configuration import Configuration
 from crawlee.enqueue_strategy import EnqueueStrategy
 from crawlee.errors import (
     ContextPipelineInitializationError,
@@ -35,7 +34,6 @@
     SessionError,
     UserDefinedErrorHandlerError,
 )
-from crawlee.events import LocalEventManager
 from crawlee.http_clients import HttpxHttpClient
 from crawlee.log_config import CrawleeLogFormatter
 from crawlee.models import BaseRequestData, DatasetItemsListPage, Request, RequestState
@@ -47,6 +45,8 @@
 if TYPE_CHECKING:
     import re
 
+    from crawlee.configuration import Configuration
+    from crawlee.events.event_manager import EventManager
     from crawlee.http_clients import BaseHttpClient, HttpResponse
     from crawlee.proxy_configuration import ProxyConfiguration, ProxyInfo
     from crawlee.sessions import Session
@@ -77,6 +77,7 @@ class BasicCrawlerOptions(TypedDict, Generic[TCrawlingContext]):
     retry_on_blocked: NotRequired[bool]
     proxy_configuration: NotRequired[ProxyConfiguration]
     statistics: NotRequired[Statistics[StatisticsState]]
+    event_manager: NotRequired[EventManager]
     configure_logging: NotRequired[bool]
     _context_pipeline: NotRequired[ContextPipeline[TCrawlingContext]]
     _additional_context_managers: NotRequired[Sequence[AsyncContextManager]]
@@ -111,6 +112,7 @@ def __init__(
         retry_on_blocked: bool = True,
         proxy_configuration: ProxyConfiguration | None = None,
         statistics: Statistics | None = None,
+        event_manager: EventManager | None = None,
         configure_logging: bool = True,
         _context_pipeline: ContextPipeline[TCrawlingContext] | None = None,
         _additional_context_managers: Sequence[AsyncContextManager] | None = None,
@@ -138,6 +140,7 @@ def __init__(
             retry_on_blocked: If set to True, the crawler will try to automatically bypass any detected bot protection
             proxy_configuration: A HTTP proxy configuration to be used for making requests
             statistics: A preconfigured `Statistics` instance if you wish to use non-default configuration
+            event_manager: A custom `EventManager` instance if you wish to use a non-default one
             configure_logging: If set to True, the crawler will configure the logging infrastructure
             _context_pipeline: Allows extending the request lifecycle and modifying the crawling context.
                 This parameter is meant to be used by child classes, not when BasicCrawler is instantiated directly.
@@ -164,7 +167,7 @@ def __init__(
         self._max_session_rotations = max_session_rotations
 
         self._request_provider = request_provider
-        self._configuration = configuration or Configuration.get_global_configuration()
+        self._configuration = configuration or service_container.get_configuration()
 
         self._request_handler_timeout = request_handler_timeout
         self._internal_timeout = (
@@ -175,8 +178,7 @@ def __init__(
 
         self._tld_extractor = TLDExtract(cache_dir=tempfile.TemporaryDirectory().name)
 
-        self._event_manager = LocalEventManager()  # TODO: switch based on configuration
-        # https://github.com/apify/crawlee-py/issues/83
+        self._event_manager = event_manager or service_container.get_event_manager()
         self._snapshotter = Snapshotter(self._event_manager)
         self._pool = AutoscaledPool(
             system_status=SystemStatus(self._snapshotter),

src/crawlee/configuration.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from datetime import timedelta
-from typing import Annotated, ClassVar, cast
+from typing import Annotated
 
 from pydantic import AliasChoices, Field
 from pydantic_settings import BaseSettings, SettingsConfigDict
@@ -22,8 +22,6 @@ class Configuration(BaseSettings):
         purge_on_start: Whether to purge the storage on start.
     """
 
-    _default_instance: ClassVar[Self | None] = None
-
     model_config = SettingsConfigDict(populate_by_name=True)
 
     internal_timeout: Annotated[timedelta | None, Field(alias='crawlee_internal_timeout')] = None
@@ -206,12 +204,19 @@ class Configuration(BaseSettings):
         ),
     ] = False
 
-    in_cloud: Annotated[bool, Field(alias='crawlee_in_cloud')] = False
-
     @classmethod
     def get_global_configuration(cls) -> Self:
         """Retrieve the global instance of the configuration."""
-        if Configuration._default_instance is None:
-            Configuration._default_instance = cls()
+        from crawlee import service_container
+
+        if service_container.get_configuration_if_set() is None:
+            service_container.set_configuration(cls())
+
+        global_instance = service_container.get_configuration()
+
+        if not isinstance(global_instance, cls):
+            raise TypeError(
+                f'Requested global configuration object of type {cls}, but {global_instance.__class__} was found'
+            )
 
-        return cast(Self, Configuration._default_instance)
+        return global_instance

src/crawlee/memory_storage_client/request_queue_client.py

@@ -30,7 +30,6 @@
     ProcessedRequest,
     ProlongRequestLockResponse,
     Request,
-    RequestListResponse,
     RequestQueueHead,
     RequestQueueHeadWithLocks,
     RequestQueueMetadata,
@@ -215,7 +214,14 @@ async def list_head(self, *, limit: int | None = None) -> RequestQueueHead:
 
     @override
     async def list_and_lock_head(self, *, lock_secs: int, limit: int | None = None) -> RequestQueueHeadWithLocks:
-        raise NotImplementedError('This method is not supported in memory storage.')
+        result = await self.list_head(limit=limit)
+        return RequestQueueHeadWithLocks(
+            lock_secs=lock_secs,
+            limit=result.limit,
+            had_multiple_clients=result.had_multiple_clients,
+            queue_modified_at=result.queue_modified_at,
+            items=result.items,
+        )
 
     @override
     async def add_request(
@@ -380,7 +386,7 @@ async def prolong_request_lock(
         forefront: bool = False,
         lock_secs: int,
     ) -> ProlongRequestLockResponse:
-        raise NotImplementedError('This method is not supported in memory storage.')
+        return ProlongRequestLockResponse(lock_expires_at=datetime.now(timezone.utc))
 
     @override
     async def delete_request_lock(
@@ -389,7 +395,7 @@ async def delete_request_lock(
         *,
         forefront: bool = False,
     ) -> None:
-        raise NotImplementedError('This method is not supported in memory storage.')
+        return None
 
     @override
     async def batch_add_requests(
@@ -431,15 +437,6 @@ async def batch_add_requests(
     async def batch_delete_requests(self, requests: list[Request]) -> BatchRequestsOperationResponse:
         raise NotImplementedError('This method is not supported in memory storage.')
 
-    @override
-    async def list_requests(
-        self,
-        *,
-        limit: int | None = None,
-        exclusive_start_id: str | None = None,
-    ) -> RequestListResponse:
-        raise NotImplementedError('This method is not supported in memory storage.')
-
     async def update_timestamps(self, *, has_been_modified: bool) -> None:
         """Update the timestamps of the request queue."""
         self._accessed_at = datetime.now(timezone.utc)

src/crawlee/models.py

@@ -350,7 +350,6 @@ class RequestQueueHeadWithLocks(RequestQueueHead):
     """Model for request queue head with locks."""
 
     lock_secs: Annotated[int, Field(alias='lockSecs')]
-    items: Annotated[list[Request], Field(alias='items', default_factory=list)]
 
 
 class BaseListPage(BaseModel):
@@ -449,13 +448,3 @@ class BatchRequestsOperationResponse(BaseModel):
 
     processed_requests: Annotated[list[ProcessedRequest], Field(alias='processedRequests')]
     unprocessed_requests: Annotated[list[UnprocessedRequest], Field(alias='unprocessedRequests')]
-
-
-class RequestListResponse(BaseModel):
-    """Response to a request list call."""
-
-    model_config = ConfigDict(populate_by_name=True)
-
-    limit: Annotated[int, Field()]
-    exclusive_start_key: Annotated[str | None, Field(alias='exclusiveStartId')]
-    items: Annotated[list[Request], Field()]

src/crawlee/service_container.py

@@ -0,0 +1,126 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Literal
+
+from typing_extensions import NotRequired, TypedDict
+
+from crawlee.configuration import Configuration
+from crawlee.events.local_event_manager import LocalEventManager
+from crawlee.memory_storage_client.memory_storage_client import MemoryStorageClient
+
+if TYPE_CHECKING:
+    from crawlee.base_storage_client.base_storage_client import BaseStorageClient
+    from crawlee.events.event_manager import EventManager
+
+
+StorageClientType = Literal['cloud', 'local']
+
+
+class _Services(TypedDict):
+    local_storage_client: NotRequired[BaseStorageClient]
+    cloud_storage_client: NotRequired[BaseStorageClient]
+    configuration: NotRequired[Configuration]
+    event_manager: NotRequired[EventManager]
+
+
+_services = _Services()
+_default_storage_client_type: StorageClientType = 'local'
+
+
+class ServiceConflictError(RuntimeError):
+    """Thrown when a service is getting reconfigured."""
+
+    def __init__(self, service_name: str, new_value: object, old_value: object) -> None:
+        super().__init__(
+            f"Service '{service_name}' was already set (existing value is '{old_value}', new value is '{new_value}')."
+        )
+
+
+def get_storage_client(*, client_type: StorageClientType | None = None) -> BaseStorageClient:
+    """Get the storage client instance for the current environment.
+
+    Args:
+        client_type: Allows retrieving a specific storage client type, regardless of where we are running.
+
+    Returns:
+        The current storage client instance.
+    """
+    if client_type is None:
+        client_type = _default_storage_client_type
+
+    if client_type == 'cloud':
+        if 'cloud_storage_client' not in _services:
+            raise RuntimeError('Cloud client was not provided.')
+        return _services['cloud_storage_client']
+
+    if 'local_storage_client' not in _services:
+        _services['local_storage_client'] = MemoryStorageClient()
+
+    return _services['local_storage_client']
+
+
+def set_local_storage_client(local_client: BaseStorageClient) -> None:
+    """Set the local storage client instance.
+
+    Args:
+        local_client: The local storage client instance.
+    """
+    if (existing_service := _services.get('local_storage_client')) and existing_service is not local_client:
+        raise ServiceConflictError('local_storage_client', local_client, existing_service)
+
+    _services['local_storage_client'] = local_client
+
+
+def set_cloud_storage_client(cloud_client: BaseStorageClient) -> None:
+    """Set the cloud storage client instance.
+
+    Args:
+        cloud_client: The cloud storage client instance.
+    """
+    if (existing_service := _services.get('cloud_storage_client')) and existing_service is not cloud_client:
+        raise ServiceConflictError('cloud_storage_client', cloud_client, existing_service)
+
+    _services['cloud_storage_client'] = cloud_client
+
+
+def set_default_storage_client_type(client_type: StorageClientType) -> None:
+    """Set the default storage client type."""
+    global _default_storage_client_type  # noqa: PLW0603
+    _default_storage_client_type = client_type
+
+
+def get_configuration() -> Configuration:
+    """Get the configuration object."""
+    if 'configuration' not in _services:
+        _services['configuration'] = Configuration()
+
+    return _services['configuration']
+
+
+def get_configuration_if_set() -> Configuration | None:
+    """Get the configuration object, or None if it hasn't been set yet."""
+    return _services.get('configuration')
+
+
+def set_configuration(configuration: Configuration) -> None:
+    """Set the configuration object."""
+    if (existing_service := _services.get('configuration')) and existing_service is not configuration:
+        raise ServiceConflictError('configuration', configuration, existing_service)
+
+    _services['configuration'] = configuration
+
+
+def get_event_manager() -> EventManager:
+    """Get the event manager."""
+    if 'event_manager' not in _services:
+        _services['event_manager'] = LocalEventManager()
+
+    return _services['event_manager']
+
+
+def set_event_manager(event_manager: EventManager) -> None:
+    """Set the event manager."""
+    if (existing_service := _services.get('event_manager')) and existing_service is not event_manager:
+        raise ServiceConflictError('event_manager', event_manager, existing_service)
+
+    _services['event_manager'] = event_manager

src/crawlee/statistics/statistics.py

@@ -8,8 +8,8 @@
 
 from typing_extensions import Self, TypeVar
 
+import crawlee.service_container
 from crawlee._utils.recurring_task import RecurringTask
-from crawlee.events import LocalEventManager
 from crawlee.events.types import Event, EventPersistStateData
 from crawlee.statistics import FinalStatistics, StatisticsPersistedState, StatisticsState
 from crawlee.statistics.error_tracker import ErrorTracker
@@ -85,7 +85,7 @@ def __init__(
         self.error_tracker = ErrorTracker()
         self.error_tracker_retry = ErrorTracker()
 
-        self._events = event_manager or LocalEventManager()
+        self._events = event_manager or crawlee.service_container.get_event_manager()
 
         self._requests_in_progress = dict[str, RequestProcessingRecord]()