Make EventStream, EventCategory, StreamIdentifier and CategoryIdentifier generic across the category name

src/logicblocks/event/store/store.py

@@ -25,7 +25,9 @@
 _default_logger = structlog.get_logger("logicblocks.event.store")
 
 
-class EventStream(EventSource[StreamIdentifier, StoredEvent]):
+class EventStream[Category: str = str](
+    EventSource[StreamIdentifier[Category], StoredEvent]
+):
     """A class for interacting with a specific stream of events.
 
     Events can be published into the stream using the `publish` method, and
@@ -36,7 +38,7 @@ class EventStream(EventSource[StreamIdentifier, StoredEvent]):
     def __init__(
         self,
         adapter: EventStorageAdapter,
-        stream: StreamIdentifier,
+        stream: StreamIdentifier[Category],
         logger: FilteringBoundLogger = _default_logger,
     ):
         self._adapter = adapter
@@ -46,7 +48,7 @@ def __init__(
         self._identifier = stream
 
     @property
-    def identifier(self) -> StreamIdentifier:
+    def identifier(self) -> StreamIdentifier[Category]:
         return self._identifier
 
     async def latest(self) -> StoredEvent | None:
@@ -129,11 +131,13 @@ def __eq__(self, other: Any) -> bool:
             return NotImplemented
         return (
             self._adapter == other._adapter
-            and self._identifier == other._identifier
+            and self._identifier == other._identifier  # pyright: ignore [reportUnknownMemberType]
         )
 
 
-class EventCategory(EventSource[CategoryIdentifier, StoredEvent]):
+class EventCategory[Category: str = str](
+    EventSource[CategoryIdentifier[Category], StoredEvent]
+):
     """A class for interacting with a specific category of events.
 
     Since a category consists of zero or more streams, the category
@@ -146,22 +150,22 @@ class EventCategory(EventSource[CategoryIdentifier, StoredEvent]):
     def __init__(
         self,
         adapter: EventStorageAdapter,
-        category: CategoryIdentifier,
+        category: CategoryIdentifier[Category],
         logger: FilteringBoundLogger = _default_logger,
     ):
         self._adapter = adapter
         self._logger = logger.bind(category=category.category)
         self._identifier = category
 
     @property
-    def identifier(self) -> CategoryIdentifier:
+    def identifier(self) -> CategoryIdentifier[Category]:
         return self._identifier
 
     async def latest(self) -> StoredEvent | None:
         await self._logger.adebug("event.category.reading-latest")
         return await self._adapter.latest(target=self._identifier)
 
-    def stream(self, *, stream: str) -> EventStream:
+    def stream(self, *, stream: str) -> EventStream[Category]:
         """Get a stream of events in the category.
 
         Args:
@@ -213,7 +217,7 @@ def __eq__(self, other: Any) -> bool:
             return NotImplemented
         return (
             self._adapter == other._adapter
-            and self._identifier == other._identifier
+            and self._identifier == other._identifier  # pyright: ignore [reportUnknownMemberType]
         )
 
 
@@ -296,7 +300,9 @@ def __init__(
         self._adapter = adapter
         self._logger = logger
 
-    def stream(self, *, category: str, stream: str) -> EventStream:
+    def stream[Category: str](
+        self, *, category: Category, stream: str
+    ) -> EventStream[Category]:
         """Get a stream of events from the store.
 
         This method alone doesn't result in any IO, it instead returns a scoped
@@ -320,7 +326,9 @@ def stream(self, *, category: str, stream: str) -> EventStream:
             stream=StreamIdentifier(category=category, stream=stream),
         )
 
-    def category(self, *, category: str) -> EventCategory:
+    def category[Category: str = str](
+        self, *, category: Category
+    ) -> EventCategory[Category]:
         """Get a category of events from the store.
 
         This method alone doesn't result in any IO, it instead returns a scoped

src/logicblocks/event/types/identifier.py

@@ -1,11 +1,13 @@
 from abc import ABC, abstractmethod
 from collections.abc import Callable
 from dataclasses import dataclass
-from typing import Literal, TypedDict
+from typing import Generic, Literal, TypedDict, TypeVar
 
 from . import default_serialisation_fallback
 from .json import JsonValue, JsonValueSerialisable
 
+Category = TypeVar("Category", default=str, bound=str, covariant=True)
+
 
 class Identifier(ABC, JsonValueSerialisable):
     @abstractmethod
@@ -81,10 +83,10 @@ def __repr__(self) -> str:
 
 
 @dataclass(frozen=True)
-class CategoryIdentifier(EventSourceIdentifier):
+class CategoryIdentifier(EventSourceIdentifier, Generic[Category]):
     __hash__ = Identifier.__hash__
 
-    category: str
+    category: Category
 
     def serialise(
         self,
@@ -124,10 +126,10 @@ def __repr__(self) -> str:
 
 
 @dataclass(frozen=True)
-class StreamIdentifier(EventSourceIdentifier):
+class StreamIdentifier(EventSourceIdentifier, Generic[Category]):
     __hash__ = Identifier.__hash__
 
-    category: str
+    category: Category
     stream: str
 
     def serialise(