Matt Van Horn 3949340610
fix: harden Postgres async engine with pool_recycle and command_timeout to stop stale-connection 504s (#4230)
* fix: harden Postgres async engine with pool_recycle and command_timeout to stop stale-connection 504s

* fix(persistence): make postgres command timeout a configurable database setting

Default the app-ORM command timeout to 30s (below nginx's 60s proxy deadline), expose it as database.command_timeout with null to disable, and add regression coverage. Addresses P1 review feedback.

Signed-off-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>

* fix(persistence): decouple DB command timeout from nonexistent proxy deadline

The command timeout bounds stalled ORM queries independently; drop the incorrect
coupling to a 60s nginx deadline (actual proxy timeout is 600s).

* feat(config): make pool_recycle configurable

Expose pool_recycle alongside command_timeout and pool_size in config,
example config, and the helm chart, keeping the 300s default, per
review.

---------

Signed-off-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
2026-07-21 08:52:31 +08:00

116 lines
4.4 KiB
Python

"""Unified database backend configuration.
Controls BOTH the LangGraph checkpointer and the DeerFlow application
persistence layer (runs, threads metadata, users, etc.). The user
configures one backend; the system handles physical separation details.
SQLite mode: checkpointer and app share a single .db file
({sqlite_dir}/deerflow.db) with WAL journal mode enabled on every
connection. WAL allows concurrent readers and a single writer without
blocking, making a unified file safe for both workloads. Writers
that contend for the lock wait via the default 5-second sqlite3
busy timeout rather than failing immediately.
Postgres mode: both use the same database URL but maintain independent
connection pools with different lifecycles.
Memory mode: checkpointer uses MemorySaver, app uses in-memory stores.
No database is initialized.
Sensitive values (postgres_url) should use $VAR syntax in config.yaml
to reference environment variables from .env:
database:
backend: postgres
postgres_url: $DATABASE_URL
The $VAR resolution is handled by AppConfig.resolve_env_variables()
before this config is instantiated -- DatabaseConfig itself does not
need to do any environment variable processing.
"""
from __future__ import annotations
import os
from typing import Literal
from pydantic import BaseModel, Field
class DatabaseConfig(BaseModel):
backend: Literal["memory", "sqlite", "postgres"] = Field(
default="memory",
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."),
)
sqlite_dir: str = Field(
default=".deer-flow/data",
description=("Directory for the SQLite database file. Both checkpointer and application data share {sqlite_dir}/deerflow.db."),
)
postgres_url: str = Field(
default="",
description=(
"PostgreSQL connection URL, shared by checkpointer and app. "
"Use $DATABASE_URL in config.yaml to reference .env. "
"Example: postgresql://user:pass@host:5432/deerflow "
"(the +asyncpg driver suffix is added automatically where needed)."
),
)
echo_sql: bool = Field(
default=False,
description="Echo all SQL statements to log (debug only).",
)
pool_size: int = Field(
default=5,
description="Connection pool size for the app ORM engine (postgres only).",
)
pool_recycle: int = Field(
default=300,
gt=0,
description="Seconds before app ORM PostgreSQL connections are recycled.",
)
command_timeout: float | None = Field(
default=30,
gt=0,
description="Timeout in seconds for app ORM PostgreSQL commands. Set to null to disable the command timeout.",
)
# -- Derived helpers (not user-configured) --
@property
def _resolved_sqlite_dir(self) -> str:
"""Resolve sqlite_dir to an absolute path (relative to CWD)."""
from pathlib import Path
return str(Path(self.sqlite_dir).resolve())
@property
def sqlite_path(self) -> str:
"""Unified SQLite file path shared by checkpointer and app."""
return os.path.join(self._resolved_sqlite_dir, "deerflow.db")
# Backward-compatible aliases
@property
def checkpointer_sqlite_path(self) -> str:
"""SQLite file path for the LangGraph checkpointer (alias for sqlite_path)."""
return self.sqlite_path
@property
def app_sqlite_path(self) -> str:
"""SQLite file path for application ORM data (alias for sqlite_path)."""
return self.sqlite_path
@property
def app_sqlalchemy_url(self) -> str:
"""SQLAlchemy async URL for the application ORM engine."""
if self.backend == "sqlite":
return f"sqlite+aiosqlite:///{self.sqlite_path}"
if self.backend == "postgres":
url = self.postgres_url
if url.startswith("postgresql://"):
url = url.replace("postgresql://", "postgresql+asyncpg://", 1)
elif url.startswith("postgres://"):
# libpq's short alias: accepted by the psycopg checkpointer, but not a SQLAlchemy dialect.
url = url.replace("postgres://", "postgresql+asyncpg://", 1)
return url
raise ValueError(f"No SQLAlchemy URL for backend={self.backend!r}")