rayhpeng
4810898cfa
Python's sqlite3 driver defaults to a 5-second busy timeout via the ``timeout`` kwarg of ``sqlite3.connect``, and aiosqlite + SQLAlchemy's aiosqlite dialect inherit that default. Setting ``PRAGMA busy_timeout=5000`` explicitly was a no-op — verified by reading back the PRAGMA on a fresh connection (it already reports 5000ms without our PRAGMA). Concurrent stress test (50 checkpoint writes + 20 event batches + 50 thread_meta updates on the same deerflow.db) still completes with zero errors and 200/200 rows after removing the explicit PRAGMA. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
103 lines
3.8 KiB
Python
103 lines
3.8 KiB
Python
"""Unified database backend configuration.
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Controls BOTH the LangGraph checkpointer and the DeerFlow application
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persistence layer (runs, threads metadata, users, etc.). The user
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configures one backend; the system handles physical separation details.
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SQLite mode: checkpointer and app share a single .db file
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({sqlite_dir}/deerflow.db) with WAL journal mode enabled on every
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connection. WAL allows concurrent readers and a single writer without
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blocking, making a unified file safe for both workloads. Writers
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that contend for the lock wait via the default 5-second sqlite3
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busy timeout rather than failing immediately.
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Postgres mode: both use the same database URL but maintain independent
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connection pools with different lifecycles.
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Memory mode: checkpointer uses MemorySaver, app uses in-memory stores.
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No database is initialized.
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Sensitive values (postgres_url) should use $VAR syntax in config.yaml
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to reference environment variables from .env:
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database:
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backend: postgres
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postgres_url: $DATABASE_URL
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The $VAR resolution is handled by AppConfig.resolve_env_variables()
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before this config is instantiated -- DatabaseConfig itself does not
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need to do any environment variable processing.
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"""
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from __future__ import annotations
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import os
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from typing import Literal
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from pydantic import BaseModel, Field
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class DatabaseConfig(BaseModel):
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backend: Literal["memory", "sqlite", "postgres"] = Field(
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default="memory",
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description=("Storage backend for both checkpointer and application data. 'memory' for development (no persistence across restarts), 'sqlite' for single-node deployment, 'postgres' for production multi-node deployment."),
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)
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sqlite_dir: str = Field(
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default=".deer-flow/data",
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description=("Directory for the SQLite database file. Both checkpointer and application data share {sqlite_dir}/deerflow.db."),
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)
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postgres_url: str = Field(
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default="",
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description=(
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"PostgreSQL connection URL, shared by checkpointer and app. "
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"Use $DATABASE_URL in config.yaml to reference .env. "
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"Example: postgresql://user:pass@host:5432/deerflow "
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"(the +asyncpg driver suffix is added automatically where needed)."
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),
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)
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echo_sql: bool = Field(
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default=False,
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description="Echo all SQL statements to log (debug only).",
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)
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pool_size: int = Field(
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default=5,
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description="Connection pool size for the app ORM engine (postgres only).",
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)
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# -- Derived helpers (not user-configured) --
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@property
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def _resolved_sqlite_dir(self) -> str:
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"""Resolve sqlite_dir to an absolute path (relative to CWD)."""
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from pathlib import Path
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return str(Path(self.sqlite_dir).resolve())
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@property
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def sqlite_path(self) -> str:
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"""Unified SQLite file path shared by checkpointer and app."""
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return os.path.join(self._resolved_sqlite_dir, "deerflow.db")
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# Backward-compatible aliases
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@property
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def checkpointer_sqlite_path(self) -> str:
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"""SQLite file path for the LangGraph checkpointer (alias for sqlite_path)."""
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return self.sqlite_path
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@property
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def app_sqlite_path(self) -> str:
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"""SQLite file path for application ORM data (alias for sqlite_path)."""
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return self.sqlite_path
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@property
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def app_sqlalchemy_url(self) -> str:
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"""SQLAlchemy async URL for the application ORM engine."""
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if self.backend == "sqlite":
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return f"sqlite+aiosqlite:///{self.sqlite_path}"
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if self.backend == "postgres":
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url = self.postgres_url
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if url.startswith("postgresql://"):
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url = url.replace("postgresql://", "postgresql+asyncpg://", 1)
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return url
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raise ValueError(f"No SQLAlchemy URL for backend={self.backend!r}")
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