Logging stdout to gunicorn access log?

问题

When I wrap my Flask application in gunicorn writing to stdout no longer seems to go anywhere (simple print statements don't appear). Is there someway to either capture the stdout into the gunicorn access log, or get a handle to the access log and write to it directly?

回答1:

Use the logging: set the stream to stdout

import logging

app.logger.addHandler(logging.StreamHandler(sys.stdout))
app.logger.setLevel(logging.DEBUG)

app.logger.debug("Hello World")

回答2:

The solution from John mee works, but it duplicates log entries in the stdout from gunicorn.

I used this:

import logging
from flask import Flask

app = Flask(__name__)

if __name__ != '__main__':
    gunicorn_logger = logging.getLogger('gunicorn.error')
    app.logger.handlers = gunicorn_logger.handlers
    app.logger.setLevel(gunicorn_logger.level)

and got I this from: https://medium.com/@trstringer/logging-flask-and-gunicorn-the-manageable-way-2e6f0b8beb2f

回答3:

You can redirect standard output to a errorlog file, which is enough for me.

Note that:

capture_output

--capture-output
False
Redirect stdout/stderr to specified file in errorlog

My config file gunicorn.config.py setting

accesslog = 'gunicorn.log'
errorlog = 'gunicorn.error.log'
capture_output = True

Then run with gunicorn app_py:myapp -c gunicorn.config.py

The equivaluent command line would be

gunicorn app_py:myapp --error-logfile gunicorn.error.log --access-logfile gunicorn.log --capture-output

回答4:

The official Flask documentation on logging works for gunicorn. https://flask.palletsprojects.com/en/1.1.x/logging/#basic-configuration

some example code to try out:

from logging.config import dictConfig

from flask import Flask

dictConfig(
    {
        "version": 1,
        "formatters": {
            "default": {
                "format": "[%(asctime)s] %(levelname)s in %(module)s: %(message)s",
            }
        },
        "handlers": {
            "wsgi": {
                "class": "logging.StreamHandler",
                "stream": "ext://flask.logging.wsgi_errors_stream",
                "formatter": "default",
            }
        },
        "root": {"level": "DEBUG", "handlers": ["wsgi"]},
    }
)
app = Flask(__name__)


@app.route("/")
def hello():
    app.logger.debug("this is a DEBUG message")
    app.logger.info("this is an INFO message")
    app.logger.warning("this is a WARNING message")
    app.logger.error("this is an ERROR message")
    app.logger.critical("this is a CRITICAL message")
    return "hello world"

run with gunicorn

gunicorn -w 2 -b 127.0.0.1:5000 app:app

request it using curl

curl http://127.0.0.1:5000

this would generate the following logs

 gunicorn -w 2 -b 127.0.0.1:5000 app:app
[2020-08-20 16:52:49 +0100] [91515] [INFO] Starting gunicorn 20.0.4
[2020-08-20 16:52:49 +0100] [91515] [INFO] Listening at: http://127.0.0.1:5000 (91515)
[2020-08-20 16:52:49 +0100] [91515] [INFO] Using worker: sync
[2020-08-20 16:52:49 +0100] [91518] [INFO] Booting worker with pid: 91518
[2020-08-20 16:52:49 +0100] [91527] [INFO] Booting worker with pid: 91527
[2020-08-20 16:52:51,172] DEBUG in app: this is a DEBUG message
[2020-08-20 16:52:51,172] INFO in app: this is an INFO message
[2020-08-20 16:52:51,173] WARNING in app: this is a WARNING message
[2020-08-20 16:52:51,173] ERROR in app: this is an ERROR message
[2020-08-20 16:52:51,173] CRITICAL in app: this is a CRITICAL message

来源：https://stackoverflow.com/questions/21399680/logging-stdout-to-gunicorn-access-log

标签

Flask

gunicorn