Configuration

Basics#

app = Sanic("myapp")
app.config.DB_NAME = "appdb"
app.config["DB_USER"] = "appuser"

db_settings = {
    'DB_HOST': 'localhost',
    'DB_NAME': 'appdb',
    'DB_USER': 'appuser'
}
app.config.update(db_settings)

Loading#

Environment variables#

$ export SANIC_REQUEST_TIMEOUT=10

>>> print(app.config.REQUEST_TIMEOUT)
10

$ export MYAPP_REQUEST_TIMEOUT=10

>>> app = Sanic(__name__, env_prefix='MYAPP_')
>>> print(app.config.REQUEST_TIMEOUT)
10

app = Sanic(__name__, load_env=False)

Using Sanic.update_config#

The Sanic instance has a very versatile method for loading config: app.update_config. You can feed it a path to a file, a dictionary, a class, or just about any other sort of object.

From a file#

# my_config.py
A = 1
B = 2

>>> app.update_config("/path/to/my_config.py")
>>> print(app.config.A)
1

$ export my_path="/path/to"

app.update_config("${my_path}/my_config.py")

From a dict#

app.update_config({"A": 1, "B": 2})

From a class or object#

class MyConfig:
    A = 1
    B = 2

app.update_config(MyConfig)

app.update_config(MyConfig())

Type casting#

When loading from environment variables, Sanic will attempt to cast the values to expected Python types. This particularly applies to:

• int
• float
• bool

In regards to bool, the following case insensitive values are allowed:

• True: y, yes, yep, yup, t, true, on, enable, enabled, 1
• False: n, no, f, false, off, disable, disabled, 0

If a value cannot be cast, it will default to a str.

app = Sanic(..., config=Config(converters=[UUID]))

Builtin values#

Timeouts#

REQUEST_TIMEOUT#

A request timeout measures the duration of time between the instant when a new open TCP connection is passed to the Sanic backend server, and the instant when the whole HTTP request is received. If the time taken exceeds the REQUEST_TIMEOUT value (in seconds), this is considered a Client Error so Sanic generates an HTTP 408 response and sends that to the client. Set this parameter's value higher if your clients routinely pass very large request payloads or upload requests very slowly.

RESPONSE_TIMEOUT#

A response timeout measures the duration of time between the instant the Sanic server passes the HTTP request to the Sanic App, and the instant a HTTP response is sent to the client. If the time taken exceeds the RESPONSE_TIMEOUT value (in seconds), this is considered a Server Error so Sanic generates an HTTP 503 response and sends that to the client. Set this parameter's value higher if your application is likely to have long-running process that delay the generation of a response.

KEEP_ALIVE_TIMEOUT#

What is Keep Alive? And what does the Keep Alive Timeout value do?#

Keep-Alive is a HTTP feature introduced in HTTP 1.1. When sending a HTTP request, the client (usually a web browser application) can set a Keep-Alive header to indicate the http server (Sanic) to not close the TCP connection after it has send the response. This allows the client to reuse the existing TCP connection to send subsequent HTTP requests, and ensures more efficient network traffic for both the client and the server.

The KEEP_ALIVE config variable is set to True in Sanic by default. If you don't need this feature in your application, set it to False to cause all client connections to close immediately after a response is sent, regardless of the Keep-Alive header on the request.

The amount of time the server holds the TCP connection open is decided by the server itself. In Sanic, that value is configured using the KEEP_ALIVE_TIMEOUT value. By default, it is set to 120 seconds. This means that if the client sends a Keep-Alive header, the server will hold the TCP connection open for 120 seconds after sending the response, and the client can reuse the connection to send another HTTP request within that time.

For reference:

• Apache httpd server default keepalive timeout = 5 seconds
• Nginx server default keepalive timeout = 75 seconds
• Nginx performance tuning guidelines uses keepalive = 15 seconds
• Caddy server default keepalive timeout = 120 seconds
• IE (5-9) client hard keepalive limit = 60 seconds
• Firefox client hard keepalive limit = 115 seconds
• Opera 11 client hard keepalive limit = 120 seconds
• Chrome 13+ client keepalive limit > 300+ seconds

Proxy configuration#

See proxy configuration section