Splitsteps

[araichoor]

This PR puts as arguments the steps to be run in fba_launch (dotile, dosky, dogfa, domtl, doscnd, dotoo, dofa, dozip, doqa, domove).
Previously, those steps (initially introduced to allow debugging) were hard-coded.
Now, those are controlled by two arguments, as suggested by @schlafly:
--steps : defaulting to all steps
--nosteps : defaulting to None
Only one can be set a time.

This does not change at all the fiber assignment, but offers more flexibility.
Noticely, in prevision of running fiberassign on-the-fly, this would allow to execute a first call generating fiberassign-TILEID.fits.gz; and a second call to make the QA png file would be done just after, but wouldn t delay the operations.
It would look like:

fba_launch --nosteps qa [...] # call to generate fiberassign-TILEID.fits.gz
fba_launch --steps qa --log-stdout [...] # call to generate the QA png file, redirecting to stdout to not overwrite the log file from the first call

To achieve that we moved the fiber assignment statistics report from the make_qa() function to the launch_onetile_fa() function, and disabled all log printing in make_qa().
We also allow to run e.g. with no gfa or no sky, which could be useful for testing.

[araichoor]

@sbailey : in the perspective of fiberassign on-the-fly, we discussed with @schlafly some subtleties to move files around, required by this two-step approach.
This is because of the way the code is designed, as we prefer that the code does not work directly in the svn folder (i.e. we d prefer that args.outdir is not the svn folder).

A suggestion was to add an argument, e.g. --archivedir $FIBER_ASSIGN_DIR, which would copy the fiberassign-TILEID* files to the svn folder when those files are created.
Please let me know if you think I should implement this tomorrow, thanks!

[schlafly]

A suggestion was to add an argument, e.g. --archivedir $FIBER_ASSIGN_DIR, which would copy the fiberassign-TILEID* files to the svn folder when those files are created. Please let me know if you think I should implement this tomorrow, thanks!

I don't think we need this for tomorrow.

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[araichoor]

ok, noted for --archivedir.
I ve pushed two more small commit (one cosmetic, and one with safety checks on the --steps and --nosteps arguments).

[araichoor]

@schlafly : this optional splitting of the steps raises few potential issues, for not-regular use.
e.g. if one sets --steps tile only, the code would crash at the "move" step, as I ve hard-coded the presence of the fiberassign-TILEID.fits.gz file.
the 3 commits above fix that; though the code will still crash if some files expected by a requested step is not present, but that is what we want, I think.

[schlafly]

I agree that it's fine for something to crash if you ask for a step when the expected outputs for that step aren't available.

[sbailey]

I tested that the code produces the same answer as before if not using the --steps / --nosteps options, and that it works as expected with the primary use case of --nosteps qa (i.e. produces other outputs the same, just not the qa png file).

I'll merge now, and other refinements can come in additional PRs later.