✨ feat(db): read SQLAlchemy engine pool configuration from config file (#73) (#74)

Move hardcoded engine pool parameters (pool_size, pool_timeout,
pool_recycle, max_overflow) from factory function defaults into
PostgresConfig, allowing per-environment tuning via YAML config.
Also add pool_pre_ping (default: true) and echo_pool (default: false).

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: itisnotyourenv

config-example.yaml

@@ -9,6 +9,12 @@ postgres:
   user: "tma_user"
   password: "tma_password"
   db: "tma_db"
+  # pool_size: 30
+  # pool_timeout: 30
+  # pool_recycle: 3600
+  # max_overflow: 20
+  # pool_pre_ping: true
+  # echo_pool: false
 
 auth:
   secret_key: "secret"

src/infrastructure/config.py

@@ -11,6 +11,12 @@ class PostgresConfig(BaseModel):
     password: str
     db: str
     echo: bool = False
+    pool_size: int = 30
+    pool_timeout: int = 30
+    pool_recycle: int = 3600
+    max_overflow: int = 20
+    pool_pre_ping: bool = True
+    echo_pool: bool = False
 
     @property
     def url(self) -> str:

src/infrastructure/db/factory.py

@@ -14,20 +14,16 @@ def create_pool(db_config: PostgresConfig) -> async_sessionmaker[AsyncSession]:
     return create_session_maker(engine)
 
 
-def create_engine(
-    db_config: PostgresConfig,
-    pool_size: int = 30,
-    pool_timeout: int = 30,
-    pool_recycle: int = 3600,
-    max_overflow: int = 20,
-) -> AsyncEngine:
+def create_engine(db_config: PostgresConfig) -> AsyncEngine:
     return create_async_engine(
         url=make_url(db_config.url),
         echo=db_config.echo,
-        pool_size=pool_size,
-        pool_timeout=pool_timeout,
-        pool_recycle=pool_recycle,
-        max_overflow=max_overflow,
+        pool_size=db_config.pool_size,
+        pool_timeout=db_config.pool_timeout,
+        pool_recycle=db_config.pool_recycle,
+        max_overflow=db_config.max_overflow,
+        pool_pre_ping=db_config.pool_pre_ping,
+        echo_pool=db_config.echo_pool,
     )
 
 

tests/unit/infrastructure/test_config.py

@@ -104,6 +104,40 @@ def test_missing_required_fields(self):
         with pytest.raises(ValidationError):
             PostgresConfig()
 
+    def test_pool_defaults(self):
+        config = PostgresConfig(
+            host="localhost", port=5432, user="user", password="pass", db="db"
+        )
+
+        assert config.pool_size == 30
+        assert config.pool_timeout == 30
+        assert config.pool_recycle == 3600
+        assert config.max_overflow == 20
+        assert config.pool_pre_ping is True
+        assert config.echo_pool is False
+
+    def test_pool_custom_values(self):
+        config = PostgresConfig(
+            host="localhost",
+            port=5432,
+            user="user",
+            password="pass",
+            db="db",
+            pool_size=10,
+            pool_timeout=15,
+            pool_recycle=1800,
+            max_overflow=5,
+            pool_pre_ping=False,
+            echo_pool=True,
+        )
+
+        assert config.pool_size == 10
+        assert config.pool_timeout == 15
+        assert config.pool_recycle == 1800
+        assert config.max_overflow == 5
+        assert config.pool_pre_ping is False
+        assert config.echo_pool is True
+
     @pytest.mark.parametrize(
         "port,echo,should_raise",
         [