|
| 1 | +import json |
| 2 | +import logging |
| 3 | + |
| 4 | +from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession |
| 5 | +from sqlalchemy.orm import sessionmaker |
| 6 | +from sqlalchemy import select, delete, update |
| 7 | + |
| 8 | +from a2a.server.models import Base, TaskModel # TaskModel is our SQLAlchemy model |
| 9 | +from a2a.server.tasks.task_store import TaskStore |
| 10 | +from a2a.types import Task, TaskStatus # Task is the Pydantic model |
| 11 | + |
| 12 | +logger = logging.getLogger(__name__) |
| 13 | + |
| 14 | + |
| 15 | +class DatabaseTaskStore(TaskStore): |
| 16 | + """ |
| 17 | + SQLAlchemy-based implementation of TaskStore. |
| 18 | + Stores task objects in a database supported by SQLAlchemy. |
| 19 | + """ |
| 20 | + |
| 21 | + def __init__( |
| 22 | + self, |
| 23 | + db_url: str, |
| 24 | + create_table: bool = True, |
| 25 | + ) -> None: |
| 26 | + """ |
| 27 | + Initializes the DatabaseTaskStore. |
| 28 | +
|
| 29 | + Args: |
| 30 | + db_url: Database connection string. |
| 31 | + create_table: If true, create tasks table on initialization. |
| 32 | + """ |
| 33 | + logger.debug(f"Initializing DatabaseTaskStore with DB URL: {db_url}") |
| 34 | + self.engine = create_async_engine(db_url, echo=False) # Set echo=True for SQL logging |
| 35 | + self.async_session_maker = sessionmaker( |
| 36 | + self.engine, class_=AsyncSession, expire_on_commit=False |
| 37 | + ) |
| 38 | + self.create_table = create_table |
| 39 | + self._initialized = False |
| 40 | + |
| 41 | + async def initialize(self) -> None: |
| 42 | + """ |
| 43 | + Initialize the database and create the table if needed. |
| 44 | + """ |
| 45 | + if self._initialized: |
| 46 | + return |
| 47 | + |
| 48 | + logger.debug("Initializing database schema...") |
| 49 | + if self.create_table: |
| 50 | + async with self.engine.begin() as conn: |
| 51 | + # This will create the 'tasks' table based on TaskModel's definition |
| 52 | + await conn.run_sync(Base.metadata.create_all) |
| 53 | + self._initialized = True |
| 54 | + logger.debug("Database schema initialized.") |
| 55 | + |
| 56 | + async def close(self) -> None: |
| 57 | + """Close the database connection engine.""" |
| 58 | + if self.engine: |
| 59 | + logger.debug("Closing database engine.") |
| 60 | + await self.engine.dispose() |
| 61 | + self._initialized = False # Reset initialization status |
| 62 | + |
| 63 | + async def _ensure_initialized(self) -> None: |
| 64 | + """Ensure the database connection is initialized.""" |
| 65 | + if not self._initialized: |
| 66 | + await self.initialize() |
| 67 | + |
| 68 | + async def save(self, task: Task) -> None: |
| 69 | + """Saves or updates a task in the database.""" |
| 70 | + await self._ensure_initialized() |
| 71 | + |
| 72 | + task_data = task.model_dump() # Converts Pydantic Task to dict |
| 73 | + |
| 74 | + async with self.async_session_maker() as session: |
| 75 | + async with session.begin(): |
| 76 | + stmt_select = select(TaskModel).where(TaskModel.id == task.id) |
| 77 | + result = await session.execute(stmt_select) |
| 78 | + existing_task_model = result.scalar_one_or_none() |
| 79 | + |
| 80 | + if existing_task_model: |
| 81 | + logger.debug(f"Updating task {task.id} in the database.") |
| 82 | + update_data = { |
| 83 | + "contextId": task_data["contextId"], |
| 84 | + "kind": task_data["kind"], |
| 85 | + "status": task_data["status"], # Already a dict from model_dump |
| 86 | + "artifacts": task_data.get("artifacts"), # Already a list of dicts |
| 87 | + "history": task_data.get("history"), # Already a list of dicts |
| 88 | + "metadata": task_data.get("metadata"), # Already a dict |
| 89 | + } |
| 90 | + stmt_update = update(TaskModel).where(TaskModel.id == task.id).values(**update_data) |
| 91 | + await session.execute(stmt_update) |
| 92 | + else: |
| 93 | + logger.debug(f"Saving new task {task.id} to the database.") |
| 94 | + # Filter task_data to include only columns present in TaskModel |
| 95 | + task_model_columns = {col.name for col in TaskModel.__table__.columns} |
| 96 | + filtered_task_data = {k: v for k, v in task_data.items() if k in task_model_columns} |
| 97 | + new_task_model = TaskModel(**filtered_task_data) |
| 98 | + session.add(new_task_model) |
| 99 | + |
| 100 | + await session.commit() |
| 101 | + logger.info(f"Task {task.id} saved successfully.") |
| 102 | + |
| 103 | + async def get(self, task_id: str) -> Task | None: |
| 104 | + """Retrieves a task from the database by ID.""" |
| 105 | + await self._ensure_initialized() |
| 106 | + |
| 107 | + async with self.async_session_maker() as session: |
| 108 | + stmt = select(TaskModel).where(TaskModel.id == task_id) |
| 109 | + result = await session.execute(stmt) |
| 110 | + task_model = result.scalar_one_or_none() |
| 111 | + |
| 112 | + if task_model: |
| 113 | + task_data_from_db = { |
| 114 | + column.name: getattr(task_model, column.name) |
| 115 | + for column in task_model.__table__.columns |
| 116 | + } |
| 117 | + # Pydantic's model_validate will parse the nested dicts/lists from JSON |
| 118 | + task = Task.model_validate(task_data_from_db) |
| 119 | + logger.debug(f"Task {task_id} retrieved successfully.") |
| 120 | + return task |
| 121 | + |
| 122 | + logger.debug(f"Task {task_id} not found in store.") |
| 123 | + return None |
| 124 | + |
| 125 | + async def delete(self, task_id: str) -> None: |
| 126 | + """Deletes a task from the database by ID.""" |
| 127 | + await self._ensure_initialized() |
| 128 | + |
| 129 | + async with self.async_session_maker() as session: |
| 130 | + async with session.begin(): |
| 131 | + stmt = delete(TaskModel).where(TaskModel.id == task_id) |
| 132 | + result = await session.execute(stmt) |
| 133 | + await session.commit() |
| 134 | + |
| 135 | + if result.rowcount > 0: |
| 136 | + logger.info(f"Task {task_id} deleted successfully.") |
| 137 | + else: |
| 138 | + logger.warning( |
| 139 | + f"Attempted to delete nonexistent task with id: {task_id}" |
| 140 | + ) |
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