Logging

Hypercorn has two loggers, an access logger and an error logger. By default neither will actively log. The special value of - can be used as the logging target in order to log to stdout and stderr respectively. Any other value is considered a filepath to target.

Configuring the Python logger

The Python logger can be configured using the logconfig or logconfig_dict configuration attributes. The latter, logconfig_dict will be passed to dictConfig after the loggers have been created.

The logconfig variable should point at a file to be used by the fileConfig function. Alternatively it can point to a JSON or TOML formatted file which will be loaded and passed to the dictConfig function. To use a JSON formatted file prefix the filepath with json: and for TOML use toml:.

Configuring access logs

The access log format can be configured by specifying the atoms (see below) to include in a specific format. By default hypercorn will choose %(h)s %(l)s %(l)s %(t)s "%(r)s" %(s)s %(b)s "%(f)s" "%(a)s" as the format. The configuration variable access_log_format specifies the format used.

Access log atoms

The following atoms, a superset of those in Gunicorn, are available for use.

Identifier	Description
h	remote address
l	'-'
u	user name
t	date of the request
r	status line without query string (e.g. GET / h11)
R	status line with query string (e.g. GET /?a=b h11)
m	request method
U	URL path without query string
Uq	URL path with query string
q	query string
H	protocol
s	status
st	status phrase (e.g. OK, Forbidden, Not Found)
S	scheme {http, https, ws, wss}
B	response length
b	response length or '-' (CLF format)
f	referer
a	user agent
T	request time in seconds
D	request time in microseconds
L	request time in decimal seconds
p	process ID
{Header}i	request header
{Header}o	response header
{Variable}e	environment variable

Customising the access logger

The acces logger class can be customised by changing the access_logger_class attribute of the Config class. This is only possible when using the python based configuration file. The hypercorn.logging.AccessLogger class is used by default.