Logging to different addressees

[McA]

Hi all,

I need a recommendation. I would to like to use the logging module to
create log messages the following way:
a) Every log message does go to a admin sink.
b) The logging of special messages should go to the admin sink AND to
a sink specifically for
a certain addressee.
c) I don't want to write the log message to two different loggers for
that purpose. I would like to do it this way:
common_logger.log('bla') -> message to admin sink
certain_logger.log('something' -> message to admin sink and addressee-
sink
d) Filtering and debug level should work as expected.

I could I achieve this in a elegant way?

Best regards
Andreas Mock

 

[Vinay Sajip]

Hi all,

I need a recommendation. I would to like to use theloggingmodule to
create log messages the following way:
a) Every log message does go to a admin sink.
b) Theloggingof special messages should go to the admin sink AND to
a sink specifically for
a certain addressee.
c) I don't want to write the log message to two different loggers for
that purpose. I would like to do it this way:
common_logger.log('bla') -> message to admin sink
certain_logger.log('something' -> message to admin sink and addressee-
sink
d) Filtering and debug level should work as expected.

I could I achieve this in a elegant way?

Best regards
Andreas Mock

Add a handler to the root logger (or common_logger) to send to the
admin sink.
Add a handler to certain_logger to send to the addressee sink.
If you added the admin sink handler to the root logger, you're done.
Otherwise, you need to ensure that certain_logger is a child of
common_logger.

Regards,

Vinay Sajip

 

[McA]

Hi Vinary,

thank you for answering. I start be proud that the author of
the logging package himself is answering.

Add a handler to the root logger (or common_logger) to send to the
admin sink.

That's clear.

Add a handler to certain_logger to send to the addressee sink.

That's also clear.

If you added the admin sink handler to the root logger, you're done.

Isn't that the first thing above? What do you mean?

Otherwise, you need to ensure that certain_logger is a child of
common_logger.

What I want to code is something like that.
a) I know thet this is a message for the admin only:
admin_logger.log('blabla') (admin_logger = root_logger =
logging.get_logger(""))

b) certain_logger.log('something' => log to the root/admin/-sink as
well as to the
certain-sink.

Do I have to create a logger subclass where I do the multiplexing of
the logging messages?
I'm pretty sure I miss something. ;-)

Regards,

Vinay Sajip

Regards
Andreas Mock

 

[Vinay Sajip]

Isn't that the first thing above? What do you mean?

I gave you a choice - to add the handler to the admin_logger OR the
root logger. So I am saying here that if you added to the root logger
(and not common_logger, assuming they're different), then there's
nothing more to do...

What I want to code is something like that.
a) I know thet this is a message for the admin only:
admin_logger.log('blabla') (admin_logger = root_logger =logging.get_logger(""))

b) certain_logger.log('something' => log to the root/admin/-sink as
well as to the
certain-sink.

Do I have to create a logger subclass where I do the multiplexing of
theloggingmessages?
I'm pretty sure I miss something. ;-)

No, the logging package is designed to allow flexibility of different
events being logged to different destinations. There's no need to
subclass Logger to achieve what you're asking for. The following
script:

# simple.py
import logging

admin_logger = logging.getLogger("") # The root logger
addressee_logger = logging.getLogger("addressee")

admin_sink = logging.FileHandler("admin.log", "w")
addressee_sink = logging.FileHandler("addressee.log", "w")

admin_logger.addHandler(admin_sink)
addressee_logger.addHandler(addressee_sink)

admin_logger.setLevel(logging.DEBUG)

admin_logger.debug("This message appears in admin sink only.")
addressee_logger.debug("This message appears in both admin sink and
addressee sink."

# - end of simple.py

Generates the following results:

----------------------------------------------------------
admin.log
----------------------------------------------------------
This message appears in admin sink only.
This message appears in both admin sink and addressee sink.

----------------------------------------------------------
addressee.log
----------------------------------------------------------
This message appears in both admin sink and addressee sink.

Regards,

Vinay Sajip

 

[McA]

Hi Vinay,

thank you for being so patient.

I gave you a choice - to add the handler to the admin_logger OR the
root logger. So I am saying here that if you added to the root logger
(and not common_logger, assuming they're different), then there's
nothing more to do...

Reading the rest of your mail let me understand what you meant.

# simple.py
import logging

admin_logger = logging.getLogger("") # The root logger
addressee_logger = logging.getLogger("addressee")

admin_sink = logging.FileHandler("admin.log", "w")
addressee_sink = logging.FileHandler("addressee.log", "w")

admin_logger.addHandler(admin_sink)
addressee_logger.addHandler(addressee_sink)

admin_logger.setLevel(logging.DEBUG)

admin_logger.debug("This message appears in admin sink only.")
addressee_logger.debug("This message appears in both admin sink and
addressee sink."

Thank you for that snippet. That means, that the root-logger does
inherit
EVERY message (if it fits to the level and isn't filtered) and the
inheritage chain is build by the chosen logger names, e.g.
messages to logging.getLogger('tree.leave') would also show up in
logging.getLogger('tree') automatically?

If this is true, how can I avoid this "bubbling up" if I would like
to?
(You see, that's a new question, but I want to take the chance to get
the answers from you personally ;-)

Hope not to bother.

Best regards
Andreas Mock

 

[Vinay Sajip]

Thank you for that snippet. That means, that the root-logger does
inherit
EVERY message (if it fits to the level and isn't filtered) and the
inheritage chain is build by the chosen logger names, e.g.
messages tologging.getLogger('tree.leave') would also show up inlogging.getLogger('tree') automatically?
Yes.

If this is true, how can I avoid this "bubbling up" if I would like
to?
(You see, that's a new question, but I want to take the chance to get
the answers from you personally ;-)

Hope not to bother.

Use the propagate flag, which is mentioned in the documentation. In
fact, please make sure you've reviewed all the documentation before
posting, as the documentation is intended to answer the more
straightforward and common questions which come up.

Best regards,

Vinay Sajip

 

[McA]

Ok.


Use the propagate flag, which is mentioned in the documentation.

That's the right hint.

In fact, please make sure you've reviewed all the documentation before
posting, as the documentation is intended to answer the more
straightforward and common questions which come up.

I did it and I'll do it again.
You know, sometimes a piece of text/documentation starts to
become information for the reader when he exactly hits the
problem.

Anyway, thank you for your help and for that module.

Best regards,

Vinay Sajip

Best regards
Andreas Mock