fleet-memory/hindsight-api/hindsight_api/extensions/context.py
2025-12-22 11:05:23 +01:00

110 lines
3.6 KiB
Python

"""Extension context providing a controlled API for extensions to interact with the system."""
from abc import ABC, abstractmethod
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from hindsight_api.engine.interface import MemoryEngineInterface
class ExtensionContext(ABC):
"""
Abstract context providing a controlled API for extensions.
Extensions receive this context instead of direct access to internal
components like MemoryEngine or database connections. This provides:
- A stable API that won't break when internals change
- Security by limiting what extensions can access
- Clear documentation of what extensions can do
Built-in implementation:
hindsight_api.extensions.builtin.context.DefaultExtensionContext
Example usage in an extension:
class MyTenantExtension(TenantExtension):
async def on_startup(self) -> None:
# Run migrations for a new tenant schema
await self.context.run_migration("tenant_acme")
class MyHttpExtension(HttpExtension):
def get_router(self, memory):
# Use memory engine for custom endpoints
engine = self.context.get_memory_engine()
...
"""
@abstractmethod
async def run_migration(self, schema: str) -> None:
"""
Run database migrations for a specific schema.
This creates the schema if it doesn't exist and runs all pending
migrations. Uses advisory locks to coordinate between distributed workers.
Args:
schema: PostgreSQL schema name (e.g., "tenant_acme").
The schema will be created if it doesn't exist.
Raises:
RuntimeError: If migrations fail to complete.
Example:
# Provision a new tenant schema
await context.run_migration("tenant_acme")
"""
...
@abstractmethod
def get_memory_engine(self) -> "MemoryEngineInterface":
"""
Get the memory engine interface.
Returns the MemoryEngineInterface for performing memory operations
like retain, recall, reflect, and entity/document management.
Returns:
MemoryEngineInterface instance.
Example:
engine = context.get_memory_engine()
result = await engine.recall_async(bank_id, query)
"""
...
class DefaultExtensionContext(ExtensionContext):
"""
Default implementation of ExtensionContext.
Uses the system's database URL and migration infrastructure.
"""
def __init__(
self,
database_url: str,
memory_engine: "MemoryEngineInterface | None" = None,
):
"""
Initialize the context.
Args:
database_url: SQLAlchemy database URL for migrations.
memory_engine: Optional MemoryEngine instance for memory operations.
"""
self._database_url = database_url
self._memory_engine = memory_engine
async def run_migration(self, schema: str) -> None:
"""Run migrations for a specific schema."""
from hindsight_api.migrations import run_migrations
run_migrations(self._database_url, schema=schema)
def get_memory_engine(self) -> "MemoryEngineInterface":
"""Get the memory engine interface."""
if self._memory_engine is None:
raise RuntimeError(
"Memory engine not configured in ExtensionContext. "
"Ensure the context was created with a memory_engine parameter."
)
return self._memory_engine