logging.logger
import logging
logging.basicConfig(level=logging.WARNING)
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
logger.debug("some debugging...")
logger.error("some error...")
python logging example
# logging_example.py
import logging
# Create a custom logger
logger = logging.getLogger(__name__)
# Create handlers
c_handler = logging.StreamHandler()
f_handler = logging.FileHandler('file.log')
c_handler.setLevel(logging.WARNING)
f_handler.setLevel(logging.ERROR)
# Create formatters and add it to handlers
c_format = logging.Formatter('%(name)s - %(levelname)s - %(message)s')
f_format = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
c_handler.setFormatter(c_format)
f_handler.setFormatter(f_format)
# Add handlers to the logger
logger.addHandler(c_handler)
logger.addHandler(f_handler)
logger.warning('This is a warning')
logger.error('This is an error')
python logging basiclogging rotatingfilehandler
import logging
rfh = logging.handlers.RotatingFileHandler(
filename='foo.log',
mode='a',
maxBytes=20*1024*1024,
backupCount=2,
encoding=None,
delay=0
)
logging.basicConfig(
level=logging.DEBUG,
format="%(asctime)s %(name)-25s %(levelname)-8s %(message)s",
datefmt="%y-%m-%d %H:%M:%S",
handlers=[
rfh
]
)
logger = logging.getLogger('main')
logger.debug("test")
pythong logging logger to string
import logging
try:
from cStringIO import StringIO # Python 2
except ImportError:
from io import StringIO
class LevelFilter(logging.Filter):
def __init__(self, levels):
self.levels = levels
def filter(self, record):
return record.levelno in self.levels
log_stream = StringIO()
logging.basicConfig(stream=log_stream, level=logging.NOTSET)
logging.getLogger().addFilter(LevelFilter((logging.INFO, logging.WARNING, logging.ERROR)))
logging.info('hello world')
logging.warning('be careful!')
logging.debug("you won't see this")
logging.error('you will see this')
logging.critical('critical is no longer logged!')
print(log_stream.getvalue())
logging.debug vs logger
// get a logger instance named "com.foo"
Logger logger = Logger.getLogger("com.foo");
// Now set its level. Normally you do not need to set the
// level of a logger programmatically. This is usually done
// in configuration files.
logger.setLevel(Level.INFO);
Logger barlogger = Logger.getLogger("com.foo.Bar");
// This request is enabled, because WARN >= INFO.
logger.warn("Low fuel level.");
// This request is disabled, because DEBUG < INFO.
logger.debug("Starting search for nearest gas station.");
// The logger instance barlogger, named "com.foo.Bar",
// will inherit its level from the logger named
// "com.foo" Thus, the following request is enabled
// because INFO >= INFO.
barlogger.info("Located nearest gas station.");
// This request is disabled, because DEBUG < INFO.
barlogger.debug("Exiting gas station search");