I have minimalistic Tornado application:
import tornado.ioloop
import tornado.web
class PingHandler(tornado.web.RequestHandler):
def get(self):
self.write("pong\n")
if __name__ == "__main__":
application = tornado.web.Application([ ("/ping", PingHandler), ])
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()
Tornado keeps reporting error requests to stderr:
WARNING:tornado.access:404 GET / (127.0.0.1) 0.79ms
Question: It want to prevent it from logging error messages. How?
Tornado version 3.1; Python 2.6
Its clear that "someone" is initializing logging subsystem when we start Tornado. Here is the code from ioloop.py that reveals the mystery:
def start(self):
if not logging.getLogger().handlers:
# The IOLoop catches and logs exceptions, so it's
# important that log output be visible. However, python's
# default behavior for non-root loggers (prior to python
# 3.2) is to print an unhelpful "no handlers could be
# found" message rather than the actual log entry, so we
# must explicitly configure logging if we've made it this
# far without anything.
logging.basicConfig()
basicConfig is called and configures default stderr handler.
So to setup proper logging for tonado access, you need to:
Add a handler to tornado.access logger: logging.getLogger("tornado.access").addHandler(...)
Disable propagation for the above logger: logging.getLogger("tornado.access").propagate = False. Otherwise messages will arrive BOTH to your handler AND to stderr
The previous answer was correct, but a little incomplete. This will send everything to the NullHandler:
hn = logging.NullHandler()
hn.setLevel(logging.DEBUG)
logging.getLogger("tornado.access").addHandler(hn)
logging.getLogger("tornado.access").propagate = False
You could also quite simply (in one line) do:
logging.getLogger('tornado.access').disabled = True
Related
When I run my Python script, my print statements do not get written to the output/screen (see output below). However, in a normal Windows console/prompt (and macOs) it works: both log and print messages are written to stdout (mixed).
DEBUG:session_storage:session:getter: MainThread
DEBUG:urllib3.connectionpool:Resetting dropped connection: example.com
DEBUG:urllib3.connectionpool:https://example.com:443 "GET /QW/7720d5b252de HTTP/1.1" 200 1073
before api init
!!setting session
b
after api init
after request init
Process X-1 is running.
Got a valid value from queue
When I it CRTL-C the the text from 'before api init' onwards get printed (so after program execution).
Code:
# SETUP LOGGING
logging.basicConfig(level=logging.DEBUG)
def main():
#another process is created via multiprocessing (process duplicated?)
...
logger = logging.getLogger(__name__)
if __name__ == '__main__':
main()
Maybe it has to do with the multiprocessing part?
It's more than likely that buffering of output is to blame. Try flushing and messages should show up
# for stdout
sys.stdout.flush()
# for stderr
sys.stderr.flush()
I am using wsgi server to spawn the servers for my web application. I am having problem with information logging.
This is how I am running the app
from gevent import monkey; monkey.patch_all()
from logging.handlers import RotatingFileHandler
import logging
from app import app # this imports app
# create a file to store weblogs
log = open(ERROR_LOG_FILE, 'w'); log.seek(0); log.truncate();
log.write("Web Application Log\n"); log.close();
log_handler = RotatingFileHandler(ERROR_LOG_FILE, maxBytes =1000000, backupCount=1)
formatter = logging.Formatter(
"[%(asctime)s] {%(pathname)s:%(lineno)d} %(levelname)s - %(message)s"
)
log_handler.setFormatter(formatter)
app.logger.setLevel(logging.DEBUG)
app.logger.addHandler(log_handler)
# run the application
server= wsgi.WSGIServer(('0.0.0.0', 8080), app)
server.serve_forever()
However, on running the application it is not logging anything. I guess it must be because of WSGI server because app.logger works in the absence of WSGI. How can I log information when using WSGI?
According to the gevent uwsgi documentation you need to pass your log handler object to the WSGIServer object at creation:
log – If given, an object with a write method to which request (access) logs will be written. If not given, defaults to sys.stderr. You may pass None to disable request logging. You may use a wrapper, around e.g., logging, to support objects that don’t implement a write method. (If you pass a Logger instance, or in general something that provides a log method but not a write method, such a wrapper will automatically be created and it will be logged to at the INFO level.)
error_log – If given, a file-like object with write, writelines and flush methods to which error logs will be written. If not given, defaults to sys.stderr. You may pass None to disable error logging (not recommended). You may use a wrapper, around e.g., logging, to support objects that don’t implement the proper methods. This parameter will become the value for wsgi.errors in the WSGI environment (if not already set). (As with log, wrappers for Logger instances and the like will be created automatically and logged to at the ERROR level.)
so you should be able to do wsgi.WSGIServer(('0.0.0.0', 8080), app, log=app.logger)
You can log like this -
import logging
import logging.handlers as handlers
.
.
.
logger = logging.getLogger('MainProgram')
logger.setLevel(10)
logHandler = handlers.RotatingFileHandler(filename.log,maxBytes =1000000, backupCount=1)
logger.addHandler(logHandler)
logger.info("Logging configuration done")
.
.
.
# run the application
server= wsgi.WSGIServer(('0.0.0.0', 8080), app, log=logger)
server.serve_forever()
I'm trying to use standard Python logging module alongside with gevent. I have monkey patched threading and I expect logging to work with my app:
import gevent.monkey
gevent.monkey.patch_all()
import logging
logger = logging.getLogger()
fh = logging.FileHandler('E:\\spam.log')
fh.setLevel(logging.DEBUG)
logger.addHandler(fh)
def foo():
logger.debug('Running in foo')
gevent.sleep(0)
logger.debug('Explicit context switch to foo again')
def bar():
logger.debug('Explicit context to bar')
gevent.sleep(0)
logger.debug('Implicit context switch back to bar')
gevent.joinall([
gevent.spawn(foo),
gevent.spawn(bar),
])
Unfortunately E:\spam.log is empty and I can see no output to the console. It seems that either I haven't configured logging properly or gevent does not support it at all (which I don't believe, because gevent documentation says that it does). So, how can I log at gevent app?
You haven't configured it correctly. You need to set the DEBUG level on the logger rather than the handler, otherwise the logger's default level (WARNING) causes your debug messages to be dropped. Try doing a
logger.setLevel(logging.DEBUG)
and it should work.
How does one turn on celery logging programmatically?
From the terminal, this works fine:
celery worker -l DEBUG
When I call get_task_logger(__name__).debug('hello'), I can see the message come up in the terminal. (stdout and stderr are being displayed) I can even import logging and call logger.info('hi') and see that too. (both work)
However, while developing a task, I prefer to use a test module and call the task function directly rather than firing up a whole worker. But I can't see the log messages. I understand that Celery is redirecting everything to its internal apparatus, but I want to see the log messages on the stdout too.
How do I tell Celery to send a copy of the log messages back to stdout?
I've read a bunch of online articles about logging but it seems that a number of logging-related configuration vars from celery have been deprecated and it's unclear to me from the docs what is the supported path today.
Here is an example module that creates a celery object and attempts to log output. Nothing shows in the terminal.
example mymodule.py
from celery import Celery
import logging
from celery.utils.log import get_task_logger
app = Celery('test')
app.config_from_object('myfile', True)
get_task_logger(__name__).warn('hello world')
logging.getLogger(__name__).warn('hello world 2')
EDIT
I know that I can add a handler to redirect some of the output back to the terminal by adding a handler
log = get_task_logger(__name__)
h = logging.StreamHandler(sys.stdout)
log.addHandler(h)
But is there a "Celery way" to do this? Maybe one that lets me also have the Celery formatted lines of text.
[2014-03-02 15:51:32,949: WARNING] hello world
I have been looking at the same issue...
What seems to work best is to use the signal handler, according to http://docs.celeryproject.org/en/latest/userguide/signals.html#after-setup-logger
In your celery.py file use:
from celery.signals import after_setup_logger
import logging
#after_setup_logger.connect()
def logger_setup_handler(logger, **kwargs ):
my_handler = MyLogHandler()
my_handler.setLevel(logging.DEBUG)
my_formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') #custom formatter
my_handler.setFormatter(my_formatter)
logger.addHandler(my_handler)
logging.info("My log handler connected -> Global Logging")
if __name__ == '__main__':
app.start()
then you can define MyLogHandler() as you wish.
To send the logs to STDOUT you should also be able to use (I have not tested it):
my_handler = logging.StreamHandler(sys.stdout)
Why is it that calls to logging framework within a python service do not produce output to the log (file, stdout,...)?
My python service has the general form:
import logging
logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
fh = logging.FileHandler('out.log')
logger.addHandler(fh)
logger.error("OUTSIDE")
class Service (win32serviceutil.ServiceFramework):
_svc_name_ = "example"
_svc_display_name_ = "example"
_svc_description_ = "example"
def __init__(self,args):
logger.error("NOT LOGGED")
win32serviceutil.ServiceFramework.__init__(self,args)
self.hWaitStop = win32event.CreateEvent(None,0,0,None)
servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE,
servicemanager.PYS_SERVICE_STARTED,
(self._svc_name_,''))
def SvcStop(self):
self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
win32event.SetEvent(self.hWaitStop)
self.stop = True
def SvcDoRun(self):
self.ReportServiceStatus(win32service.SERVICE_RUNNING)
self.main()
def main(self):
# Service Logic
logger.error("NOT LOGGED EITHER")
pass
The first call to logger.error produces output, but not the two inside the service class (even after installing the service and making sure it is running).
I've found that only logging within the actual service loop works with the logging module and the log file ends up in something like C:\python27\Lib\site-packages\win32.
I abandoned logging with the logging module for Windows as it didn't seem very effective. Instead I started to use the Windows logging service, e.g. servicemanager.LogInfoMsg() and related functions. This logs events to the Windows Application log, which you can find in the Event Viewer (start->run->Event Viewer, Windows Logs folder, Application log).
You have to write the full path of the log file.
e.g.
fh = logging.FileHandler('C:\\out.log')
actually outside logger initialized twice.
these 2 outside loggers are in different processes. one is the python process and another one is windows-service process.
for some reason, the 2nd one didn't configured success, and inside loggers in this process too. that's why u cant find the inside logs.