sanic

sanic Best Practices

Sanic is built for speed and scalability. To harness its full power and maintain a robust codebase, adhere strictly to these guidelines.

1. Code Organization and Structure

Always structure your Sanic application using the factory pattern and Blueprints for modularity. Keep configuration separate.

❌ BAD: Global app instance, monolithic file

# app.py
from sanic import Sanic, response

app = Sanic("my_app") # Global instance is hard to test and configure

@app.route("/")
async def hello_world(request):
    return response.json({"message": "Hello!"})

# Configuration directly in code
app.config.DB_URL = "sqlite:///db.sqlite"

✅ GOOD: Factory pattern, Blueprints, external config

# config.py
import os

class Config:
    DB_URL = os.getenv("DB_URL", "sqlite:///db.sqlite")
    SECRET_KEY = os.getenv("SECRET_KEY", "super-secret-key")

# app.py
from sanic import Sanic
from .config import Config
from .blueprints.users import bp as users_bp
from .blueprints.auth import bp as auth_bp

def create_app() -> Sanic:
    app = Sanic("my_app")
    app.config.update(Config.__dict__) # Load config from a dedicated object

    app.blueprint(users_bp)
    app.blueprint(auth_bp)

    # Add listeners, middleware, etc. here
    @app.listener("before_server_start")
    async def setup_db(app, loop):
        # Example: Initialize a database connection pool
        app.ctx.db = "AsyncDatabaseConnection" # Placeholder for actual DB setup
        print(f"Connecting to DB: {app.config.DB_URL}")

    return app

# blueprints/users.py
from sanic import Blueprint, Request, response
from typing import Dict, Any

bp = Blueprint("users", url_prefix="/users")

@bp.route("/", methods=["GET"])
async def get_all_users(request: Request) -> response.HTTPResponse:
    # Simulate async DB call using app.ctx.db
    # await request.app.ctx.db.fetch_all("SELECT * FROM users")
    return response.json([{"id": 1, "name": "Alice"}])

@bp.route("/<user_id:int>", methods=["GET"])
async def get_user(request: Request, user_id: int) -> response.HTTPResponse:
    # Simulate async DB call
    # user = await request.app.ctx.db.fetch_one(f"SELECT * FROM users WHERE id={user_id}")
    user = {"id": user_id, "name": "Alice"} # Placeholder
    if user:
        return response.json(user)
    return response.json({"message": "User not found"}, status=404)