How to suppress web.py output?

Question

I am trying to suppress the web.py output from the console. I do not wish to suppress all output to stderr or redirect the output, but merely stop it from printing statements such as the following to the console.

127.0.0.1:57691 - - [06/Mar/2018 22:25:43] "HTTP/1.1 GET /api/getDimensionColumnConstraints" - 200 OK

I have tried adding the web.config.debug = False statement as the first line in my main() function and it still prints this for every API call.

Answer 1

The built-in server for web.py sends the HTTP info and other errors to stderr by default. I'm with you -- I want the errors, but don't want all the HTTP statements.

So, here's what you can do.

1. Create a custom Logger

2. Intercept calls within the logger, tossing out log records matching the pattern.

Not so hard, you'll create a basic wsgi application middleware to intercept:

import logging
class Log:
    def __init__(self, xapp, logname="wsgi"):
        class O:
            def __init__(self, xapp, logname="wsgi"):
                self.logger = logging.getLogger(logname)
            def write(self, s):
                if s[-1] == '\n':
                    s = s[:-1]
                if s == "":
                    return
                if self.ignore(s):
                    return
                self.logger.debug(s)
        self.app = xapp
        self.f = O(logname)
    def __call__(self, environ, start_response):
        environ['wsgi.errors'] = self.f
        return self.app(environ, start_response)

Add that middleware into your __main__ initialization of the application. You probably have something like:

if __name__ == '__main__':
    app = web.application(urls, globals())
    app.run()

Change the run() to add the middleware:

    app.run(Log)

Now the second part. See the self.ignore(s) within O.write() above? Use that to decide to process or ignore the logging statement, for example I do:

def ignore(self, s):
    if not all([web.config.get('debug_http', False),
               any(['"HTTP/1.1 GET ' in s,
                    '"HTTP/1.1 POST ' in s])]):
        return True
    return False

Which basically says if the string to print contains 'HTTP...' ignore it. I've added the check to a global flag 'debug_http', which allows me to set that (somewhere, anywhere, anyhow) to enable / disable this item.