[py-tx] Move ISignalTypeConfigStore to python-threatexchange/storage/…

…interfaces.py (#1701)

python-threatexchange/threatexchange/cli/storage/interfaces.py

@@ -0,0 +1,98 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+
+"""
+Common interface for persisting pytx configuration and concepts.
+
+Most of the individual components of pytx are find to use piecemeal, and
+the full interface covers the most complex and complete useage. A usecase
+with one collection of hashes using one algorithm might be better off 
+hardcoding those things rather than fully implementing the interface.
+
+# Migration Notes
+There's an earlier attempt at these interfaces used for CLI at
+<@Mackay-Fisher add the right pointer to the CLI storage>.
+During the development of Hasher-Matcher-Actioner 2.0 
+(github.com/facebook/ThreatExchange/tree/main/hasher-matcher-actioner/)
+we realized that the original attempt at this wouldn't meet the needs
+of that code and wrote a new interface. 
+
+As of 12/2024, we are now migrating that interface from HMA into pytx
+proper as part of a migration to dbm 
+(github.com/facebook/ThreatExchange/issues/1687). The general approach is:
+1. Copy the interface unchanged from HMA to pytx
+2. Release a new version of pytx
+3. Delete the copy in HMA and update all references to the pytx version
+
+In parallel, we intend to slowly migrate the CLI storage components to
+follow the same interface.
+"""
+
+import abc
+from dataclasses import dataclass
+import typing as t
+from threatexchange.content_type.content_base import ContentType
+from threatexchange.signal_type.signal_base import SignalType
+
+
+@dataclass
+class SignalTypeConfig:
+    """
+    Holder for SignalType configuration
+    """
+
+    # Signal types that are not enabled should not be used in hashing/matching
+    enabled_ratio: float
+    signal_type: t.Type[SignalType]
+
+    @property
+    def enabled(self) -> bool:
+        # TODO do a coin flip here, but also refactor this to do seeding
+        return self.enabled_ratio >= 0.0
+
+
+class ISignalTypeConfigStore(metaclass=abc.ABCMeta):
+    """Interface for accessing SignalType configuration"""
+
+    @abc.abstractmethod
+    def get_signal_type_configs(self) -> t.Mapping[str, SignalTypeConfig]:
+        """Return all installed signal types."""
+
+    @abc.abstractmethod
+    def _create_or_update_signal_type_override(
+        self, signal_type: str, enabled_ratio: float
+    ) -> None:
+        """Create or update database entry for a signal type, setting a new value."""
+
+    @t.final
+    def create_or_update_signal_type_override(
+        self, signal_type: str, enabled_ratio: float
+    ) -> None:
+        """Update enabled ratio of an installed signal type."""
+        installed_signal_types = self.get_signal_type_configs()
+        if signal_type not in installed_signal_types:
+            raise ValueError(f"Unknown signal type {signal_type}")
+        if not (0.0 <= enabled_ratio <= 1.0):
+            raise ValueError(
+                f"Invalid enabled ratio {enabled_ratio}. Must be in the range 0.0-1.0 inclusive."
+            )
+        self._create_or_update_signal_type_override(signal_type, enabled_ratio)
+
+    @t.final
+    def get_enabled_signal_types(self) -> t.Mapping[str, t.Type[SignalType]]:
+        """Helper shortcut for getting only enabled SignalTypes"""
+        return {
+            k: v.signal_type
+            for k, v in self.get_signal_type_configs().items()
+            if v.enabled
+        }
+
+    @t.final
+    def get_enabled_signal_types_for_content_type(
+        self, content_type: t.Type[ContentType]
+    ) -> t.Mapping[str, t.Type[SignalType]]:
+        """Helper shortcut for getting enabled types for a piece of content"""
+        return {
+            k: v.signal_type
+            for k, v in self.get_signal_type_configs().items()
+            if v.enabled and content_type in v.signal_type.get_content_types()
+        }