Add example of logging config file

[matrixise]

In the doc, there is the description of --log-config <path> for the configuration of a config file. I think an example of config file could be really awesome for the new comers.

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[tomchristie]

Agreed yup. As a starting point we could just link to this: https://docs.python.org/3/library/logging.config.html#logging-config-fileformat

Tho ideally a proper example that's relevant to uvicorn would be ace.

Any pull requests here would be most welcome (even if it's just linkig to the Python docs to start with.)

[ex-nerd]

It would also be worth mentioning that by enabling the custom log, other uvicorn loggers are likely to become disabled. See #511

[NightMachinery]

I found this helpful:

import sys
import uvicorn
from uvicorn.config import LOGGING_CONFIG

def main():
    root_path = ''
    if len(sys.argv) >= 2:
        root_path = sys.argv[1]
    ##
    # %(name)s : uvicorn, uvicorn.error, ... . Not insightful at all.
    LOGGING_CONFIG["formatters"]["access"]["fmt"] = '%(asctime)s %(levelprefix)s %(client_addr)s - "%(request_line)s" %(status_code)s'
    LOGGING_CONFIG["formatters"]["default"]["fmt"] = "%(asctime)s %(levelprefix)s %(message)s"

    date_fmt = "%Y-%m-%d %H:%M:%S"
    LOGGING_CONFIG["formatters"]["default"]["datefmt"] = date_fmt
    LOGGING_CONFIG["formatters"]["access"]["datefmt"] = date_fmt
    ##
    uvicorn.run("brishgarden.garden:app", host="127.0.0.1", port=7230, log_level="info", proxy_headers=True, root_path=root_path)

[ievgennaida]

I will appreciate good example for the uvicorn logging with other libs.
Currently I am configuring root logger and setting formatter to all the available

   for logger_name in logging.root.manager.loggerDict.keys():
        override_logger = logging.getLogger(logger_name)
        for handler in override_logger.handlers:
            handler.setFormatter(formatter)

[ievgennaida]

Do you use any config file by default when nothing is passed to the --log-config?

[mattiacampana]

I would like to specify the log configuration in a separate file and use it with the option --log-config.
In particular, I would like to add the timestamp to the logs. I've found this

LOGGING_CONFIG["formatters"]["default"]["fmt"] = "%(asctime)s [%(name)s] %(levelprefix)s %(message)s"

but I don't know how to specify it in a config file.

[euri10]

I would like to specify the log configuration in a separate file and use it with the option --log-config.
In particular, I would like to add the timestamp to the logs. I've found this

LOGGING_CONFIG["formatters"]["default"]["fmt"] = "%(asctime)s [%(name)s] %(levelprefix)s %(message)s"

but I don't know how to specify it in a config file.

assuming you're passing a yaml file, something like the below should print the timestamp, this is well explained in python docs here

version: 1
formatters:
  simple:
    format: '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
handlers:
  console:
    class: logging.StreamHandler
    level: DEBUG
    formatter: simple
    stream: ext://sys.stdout
loggers:
  simpleExample:
    level: DEBUG
    handlers: [console]
    propagate: no
root:
  level: DEBUG
  handlers: [console]

[mattiacampana]

Thank you @euri10. However, I got the following error when I try to run uvicorn with --log-config option:
configparser.MissingSectionHeaderError: File contains no section headers.
What kind of header should I use? Should I specify an additional option to use the .yaml config file?

Sorry, but this is my very first time with this problem and I'm a bit confused...

[euri10]

dunno what you're doing, seems like you're using a ini logging format ?

you can use --log-config with :

1. yaml or json, it will be detected according to the file extension (.yaml or .yml and .json) see here :

uvicorn/uvicorn/config.py

Lines 240 to 247 in bdab488

	elif self.log_config.endswith(".json"):
	with open(self.log_config) as file:
	loaded_config = json.load(file)
	logging.config.dictConfig(loaded_config)
	elif self.log_config.endswith((".yaml", ".yml")):
	with open(self.log_config) as file:
	loaded_config = yaml.safe_load(file)
	logging.config.dictConfig(loaded_config)

2. a old ini file format, with any other file extentions, I think you ended up here, in that case it means your ini format is incorrect and I can just point you at the docs I already linked above for writing the correct format

3. a dictionary, more to be use when running programmatically

for reference with the above simplest log.yaml and running ❯ uvicorn app:app --log-config=log.yaml you get the timestamp as asked:

2020-11-18 13:54:22,907 - uvicorn.access - INFO - 127.0.0.1:53346 - "GET / HTTP/1.1" 200
2020-11-18 13:54:23,238 - uvicorn.access - INFO - 127.0.0.1:53346 - "GET / HTTP/1.1" 200
2020-11-18 13:54:23,804 - uvicorn.access - INFO - 127.0.0.1:53346 - "GET / HTTP/1.1" 200

[nicoinn]

I also had @mattiacampana 's issue --- fixed by updating to the latest uvicorn with pip install -U uvicorn