Allow defining db pool size and max overflow in the settings

.env.example

@@ -1,2 +1,4 @@
 ARGOS_YAML_FILE = "my-config.yaml"
 ARGOS_DATABASE_URL = "postgresql://argos:argos@localhost/argos"
+DB_POOL_SIZE = 10
+DB_MAX_OVERFLOW = 20

argos/server/main.py

@@ -76,7 +76,19 @@ def setup_database(app):
     logger.debug(f"Using database URL {settings.database_url}")
     if settings.database_url.startswith("sqlite:////tmp"):
         logger.warning("Using sqlite in /tmp is not recommended for production")
-    engine = create_engine(settings.database_url, pool_size=10, max_overflow=20)
+    
+    extra_settings = {}
+    if settings.db_pool_size:
+        extra_settings.set("pool_size", settings.db_pool_size)
+
+    if settings.db_max_overflow:
+        extra_settings.set("max_overflow", settings.db_max_overflow)
+        
+    max_overflow=settings.db_max_overflow,
+    engine = create_engine(
+        settings.database_url,
+        **extra_settings
+    )
     app.state.SessionLocal = sessionmaker(
         autocommit=False, autoflush=False, bind=engine
     )

argos/server/settings.py

@@ -1,6 +1,7 @@
 import os
 from functools import lru_cache
 from os import environ
+from typing import Optional
 
 import yaml
 from pydantic_settings import BaseSettings, SettingsConfigDict
@@ -14,23 +15,30 @@ class Settings(BaseSettings):
     app_env: str
     database_url: str
     yaml_file: str
+    db_pool_size: Optional[int]
+    db_max_overflow: Optional[int]
 
 
 class DevSettings(Settings):
     app_env: str = "dev"
     database_url: str = "sqlite:////tmp/argos.db"
     yaml_file: str = "config.yaml"
+    db_pool_size: Optional[int] = None
+    db_max_overflow: Optional[int] = None
 
 
 class TestSettings(Settings):
     app_env: str = "test"
     yaml_file: str = "tests/config.yaml"
     database_url: str = "sqlite:////tmp/test-argos.db"
+    db_pool_size: Optional[int] = None
+    db_max_overflow: Optional[int] = None
 
 
 class ProdSettings(Settings):
     app_env: str = "prod"
-    pass
+    db_pool_size: Optional[int] = 10
+    db_max_overflow: Optional[int] = 20
 
 
 environments = {

docs/conf.py

@@ -19,7 +19,7 @@ myst_enable_extensions = ["colon_fence"]
 
 templates_path = ["_templates"]
 exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
-mermaid_params = ['--theme', 'forest']
+mermaid_params = ["--theme", "forest"]
 
 html_sidebars = {
     "**": [

pyproject.toml

@@ -41,6 +41,7 @@ dev = [
   "ipython>=8.16,<9",
   "ipdb>=0.13,<0.14",
   "sphinx-autobuild",
+  "ruff==0.1.5,<1"
 ]
 postgres = [
   "psycopg2-binary>=2.9,<3",