The IsrTask is called as a subtask to ProcessCcdTask everywhere it is invoked.  This allows it to be retargeted to the particular camera as needed.  This is not the case when called from a dedicated runIsr.py script.  IsrTask is then the main task, and cannot be retargeted.

I am looking for suggestions, as my initial idea of creating a dummy task that does nothing but setup and retarget IsrTask as a subtask does not feel like an elegant solution.

I think you need a wrapper class. It may not be completely elegant, but it's the way it needs to be done.

class IsrWrapperConfig(Config):

    isr = ConfigurableField(target=IsrTask, doc="Instrument signature removal")

class IsrWrapperTask(CmdLineTask):

    ConfigClass = IsrWrapperConfig

    def __init__(self, *args, **kwargs):

        super().__init__(*args, **kwargs)

        self.makeSubtask("isr")

    def runDataRef(self, dataRef):

        return self.isr.runDataRef(dataRef)

If you don't like that, you could stick it in pipe_drivers and have it mirror singleFrameDriver.py (isrDriver.py?), which would not just make it retargetable, but also allow you to spread it over multiple nodes.

I've written the wrapper script, and done tests with HSC data to confirm that it does something reasonable.  I've also added configuration files for the other obs_* packages.  Are there datasets and calib data already defined for these other cameras to allow them to be tested as well?

The addition of a CmdLineTask for ISR has prompted a number of configuration changes in each obs_ package to enable both `runIsr.py` and `processCcd.py` to read the same information.

This wasn't set as "In review" due to mistakes on my part.

I've tried to split up the reviewing of the obs_* packages to people with some familiarity with the data (even if it was me taking github's advice).  The ip_isr package has the most changes that are not simply splitting configuration files, and is probably helpful to understand the reason for those splits, and so I welcome comments on that package from everyone.

If anyone wants to look over any of the other packages, I'd be happy to read those comments.  I simply didn't want any one person to be surprised with a dozen sets of changes to review.

A list of package/github reviewers:

ip_isr: Jim Bosch, Paul Price, Yusra AlSayyad, Meredith Rawls, Merlin Fisher-Levine, Merlin Fisher-Levine, Dominique Boutigny
obs_base: John Parejko
obs_cfht: Dominique Boutigny
obs_ctio0m9: Merlin Fisher-Levine
obs_decam: Meredith Rawls
obs_lsstCam: Merlin Fisher-Levine
obs_lsstSim: John Parejko
obs_monocam: Paul Price
obs_sdss: Yusra AlSayyad
obs_subaru: Paul Price
obs_test: Jim Bosch

Sorry for any confusion.  The logistics on this ticket review are more complicated than I've worked with before.