Logging adapter/filter example

logging_filter_example.py

from logging import getLogger, Filter, LoggerAdapter, StreamHandler, Formatter, INFO, ERROR, DEBUG

logger = getLogger("test")

class IdaesModFilter(Filter):
    """Filter that keeps a list of allowed 'modules' in an attribute.
    """
    def __init__(self, modules):
        self.modules = modules  # list of modules to allow
    def filter(self, record):
        try:
            if record.idaesmod in self.modules:
                return 1
        except AttributeError:
            return 0
        return 0
        
idaes_filter = IdaesModFilter(["flowsheet"])


h = StreamHandler()
f = Formatter("%(asctime)s [%(levelname)s] %(idaesmod)s :: %(msg)s") # note "idaesmod"
h.setFormatter(f)
h.addFilter(idaes_filter) # add the filter to the handler
logger.addHandler(h)   # add handler to logger


# Create logger for flowsheets

fslogbase = getLogger("test.flowsheet")
fslog = LoggerAdapter(fslogbase, {"idaesmod": "flowsheet"}) # puts "idaesmod" attr in log record
fslog.setLevel(ERROR)


fslog.info("hello")  # does not pass due to level


fslog.error("hello") # passes


ulogbase = getLogger("test.unit")
ulog = LoggerAdapter(ulogbase, {"idaesmod": "unit"})  # logger for 'unit'


ulog.error("hello") # does not pass due to module unit not in filter modules


# Change filter to only pass "unit" modules

idaes_filter.modules = ["unit"]


fslog.error("hello")  # does not pass due to module flowsheet not in filter modules


ulog.error("hello") # passes


ulog.info("hello")  # does not pass due to level (still)


ulog.setLevel(INFO)


ulog.info("hello") # now it passes