This page in the Developer Guide may be useful: https://developer.lsst.io/coding/logging.html

I substituted the lsst.log.Log.getDefaultLogger() for the lsst.pex.logging.getDefaultLog(). That appeared to be the only change required.

The two loggers are not identical in behavio r(some of the methods, such as log.debug differ). But by default they log only to the screen and are unnamed.

I do not see any calls in this package which differ between the two packages.

Change is in tickets/DM-8358

This is the same change as the ci_hsc one. I would have preferred that lauren run it, since she can actually run meas_mosaic. But you can choose to review it without executing it, I believe.

Going to steal this review for myself, since I'd like to learn about the new logger. Sorry Merlin Fisher-Levine!

Lauren MacArthur has already pointed out that the import statements need fixing in mosaicTask.py. Other than that, this looks ok.

I'm not sure why "from log.lsst import Log" is preferred to "import log.lsst". Can someone help me here?

Is this a matter of style, or is it desirable not to import the entire module and then refer to log as log.lsst.Log? I imported lsst.log in other tickets, probably because I thought that some of the globals in log.lsst (such as the log level constants) were potentially useful.

Hsin-Fang Chiang, can you comment on whether there is a preferred usage?

I don't see any compelling reason to prefer one version over the other. Either is preferred to from lsst.pex.logging import getDefaultLog, which is what you have now!

Yes, I agree that this import would be bad.

That's strange. This line was not in the version Lauren reviewed. Her comment was about from ... import ... vs import ..., and my question was about that.

I think her fundamental point was simply that your imports are wrong, because you are still importing pex_logging rather that lsst.log. She then suggested one particular change, which was based on established practice elsewhere, but isn't (as far as I know) a requirement.

Indeed...my main point was that the pex_logging import needed changing. I just pointed to what seems to be the "norm", not the "enforced" (or necessarily "recommended"!) style as far as the logging updates have gone in other packages.

I made the change Lauren ask for, though I used import lsst.log in the other tickets in this sequence.

John Swinbank I think that what was in the pull request was inconsistent with what was in the ticket branch. I have a theory that I am using git incorrectly, and I will send you email to get your opinion. I think this is what is causing me to get so much trouble just before I merge to master, so that I sometimes have to end up recreating the commits on a second branch.