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log.debug should die, I think. So it probably shouldn't be documented :)

I was also told this by radix on IRC.

I see no deprecation warnings. I documented it because I noticed a colleague of mine independently found and used it, and I'd never heard of it, so I corrected that, because it's clearly part of the public API at the moment. If someone who feels confident that they understand the intent of twisted.python.log well enough wants to stick their neck out and deprecate debug, please do. I'm not that person.

Also, a few words to the effect of *why* it should be deprecated would be useful. We use it quite a lot, and I'd appreciate a few comments. It wouldn't be a big problem should it go away, since we already monkeypatch t.p.logging a lot, but it is still bewildering to see such comments without any explanation. -- Nicola Larosa - nico@tekNico.net How much of what we are should we be proud of? When did we choose the things that made us smart, knowledgeable, or successful? Should we be proud? Should we feel superior? Maybe we should just be grateful. -- jgoldblog, May 2002

On Tue, 2005-10-04 at 10:00 -0700, Scott Lamb wrote:

In my day job, I develop a lot of Java code. We have the luxury of granular logging. I can switch, on a per-class basis, the output level to trace, debug, warn, error, or fatal. That's handy.

In Twisted, I see log.msg(), log.debug(), and log.err(). Why is one of these levels going away? Is it just not normal to use logging for debugging? What do you do instead?

twisted.python.log needs to be rewritten to support more modular logging; the new API would be "log.msg(something, interface=IFoo)" where IFoo might be IMessage, or IHTTPRequest for the webserver log, etc.. We don't have thay yet, unfortunately. log.debug() as it works now is just broken, it doesn't add anything to log.msg() in a reasonable way.

On Oct 4, 2005, at 1:00 PM, Scott Lamb wrote:

On Oct 4, 2005, at 12:20 AM, Nicola Larosa wrote:

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Also, a few words to the effect of *why* it should be deprecated would be useful. We use it quite a lot, and I'd appreciate a few comments.

Me, too, me too.

In my day job, I develop a lot of Java code. We have the luxury of granular logging. I can switch, on a per-class basis, the output level to trace, debug, warn, error, or fatal. That's handy.

In Twisted, I see log.msg(), log.debug(), and log.err(). Why is one of these levels going away? Is it just not normal to use logging for debugging? What do you do instead?

The "log levels", such as they are, are (and have been for ages) implemented as keyword args on msg: log.msg("error message", isError=1) log.msg("normal message") log.msg("debug message", debug=1). The log.debug function just added the debug=1 argument for you. The log.err func is poorly named, because you might be tempted to use it to emit error-level info, when really it is for emitting Exception/ Failure objects. All in all, the log level functionality in twisted.python.log is pretty silly, but substantially unchanged. James

On Oct 4, 2005, at 5:01 PM, glyph@divmod.com wrote:

On Tue, 4 Oct 2005 16:31:58 -0400, James Y Knight wrote:

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log.msg("error message", isError=1)

Please don't ever do this. Log observers which check the isError flag expect a stricter interface; a Failure object, for one thing, like log.err puts there.

Actually they don't. They expect that the failure keyword may or may not be present. The only use of "levels" we have (DefaultObserver only showing error messages) filters out any non-isError messages, so there are circumstances in which you want to make sure you're emitting an isError=1 message.

Really this should be using the interface keyword arg that itamar mentioned, set to something like log.IErrorReport. To ensure portability when that does become the convention, use log.err.

But sometimes you cannot use log.err because you want to emit an error-level _message_, rather than the repr of an object, an exception, or a failure. Notice how log.err("Foo!") doesn't actually do what you might hope. Contrast with log.msg("Foo!", isError=1) which does. James

On Tue, Oct 04, 2005 at 11:49:04PM -0400, Jp Calderone wrote:

On Tue, 4 Oct 2005 23:18:40 -0400, James Y Knight wrote: [...]

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Notice how log.err("Foo!") doesn't actually do what you might hope. Contrast with log.msg("Foo!", isError=1) which does.

Neither of these is supported behavior. They're implementation accidents and shouldn't be used. It's understandable that this is surprising, since I doubt it's ever been written down anywhere.

Would you mind reviewing logging.xhtml to make sure it's perfectly correct about these matters, then? I made the best educated guesses about the intentions of the code that I could, but I might have made some mistakes. -Andrew.