Python/Django: log to console under runserver, log to file under Apache

Here's a Django logging-based solution. It uses the DEBUG setting rather than actually checking whether or not you're running the development server, but if you find a better way to check for that it should be easy to adapt.

LOGGING = {
    'version': 1,
    'formatters': {
        'verbose': {
            'format': '%(levelname)s %(asctime)s %(module)s %(process)d %(thread)d %(message)s'
        },
        'simple': {
            'format': '%(levelname)s %(message)s'
        },
    },
    'handlers': {
        'console': {
            'level': 'DEBUG',
            'class': 'logging.StreamHandler',
            'formatter': 'simple'
        },
        'file': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': '/path/to/your/file.log',
            'formatter': 'simple'
        },
    },
    'loggers': {
        'django': {
            'handlers': ['file'],
            'level': 'DEBUG',
            'propagate': True,
        },
    }
}

if DEBUG:
    # make all loggers use the console.
    for logger in LOGGING['loggers']:
        LOGGING['loggers'][logger]['handlers'] = ['console']

see https://docs.djangoproject.com/en/dev/topics/logging/ for details.

Text printed to stderr will show up in httpd's error log when running under mod_wsgi. You can either use print directly, or use logging instead.

print >>sys.stderr, 'Goodbye, cruel world!'