Concept of longslit workflow as an example of specreduce block structure

notebook_sandbox/longslit_blocks.py

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+"""
+This is a conceptual set of classes meant to encode the basics of a longslit
+workflow as swappable blocks.  Adapted from a whiteboard diagram from
+the 2019 Astropy Coordination Meeting (included in the PR adding this file).
+
+Two things that this file is *not* meant to imply:
+
+* The specific use or not of classes as opposed to other approaches
+  for defining interfaces.
+* Details of how the various blocks connect together.  There are a variety of
+  "pipeline" packages in the wider community, and we shouldn't be in the
+  business of duplicating that if we can reuse it.  So these blocks just assume
+  the simplistic idiom of "call the block, then manually pass it's result to the
+  next one", without anything about how you compose blocks together
+
+"""
+from dataclasses import dataclass
+from typing import Union
+from pathlib import Path
+
+
+@dataclass
+class CCDProc:
+    """
+    Note this class may not need to exist - we could just tell the users "do
+    whatever you need to do with ccdproc to get something that's been
+    overscan, bias, dark, and pixel-flat subtracted, but that results in a
+    """
+    ccdproc_subtract_background : bool
+    #... other ccdproc options ...
+
+
+    def __call__(self, rawin: Union([CCDImage,NDData])) -> CCDImage:
+        raise NotImplementedError()
+        return ccdproc_corrected_image
+
+
+@dataclass
+class CCDProc:
+    """
+    Note this class may not need to exist - we could just tell the users "do
+    whatever you need to do with ccdproc to get something that's been
+    overscan, bias, dark, and pixel-flat subtracted, but that results in a
+    """
+    ccdproc_subtract_background : bool
+    #... other ccdproc options ...
+
+
+    def __call__(self, rawin: Union([CCDImage,NDData])) -> CCDImage:
+        raise NotImplementedError()
+        return ccdproc_corrected_image
+
+@dataclass
+class AutoIdentify2D:
+    line_list : dict  # maps a name of a line to a *spectral axis unit* astropy quantity
+
+
+    def __call__(self, arcimage: CCDImage) -> WavelengthSolution:
+        raise NotImplementedError()
+        return solution
+
+@dataclass
+class AutoIdentify1D:
+    template_spectrum : Union([Path, str])  # should be a path to whatever is used as the template,
+    #,,, other autoidentify parameters
+
+    def __call__(self, arcimage: CCDImage) -> WavelengthSolution:
+        raise NotImplementedError()
+        return solution
+
+@dataclass
+class InteractiveIdentify1D:
+    """
+    This is left generally undefined in detail since it requires some form of
+    GUI interaction.  In principle it may not even best be thought of as a "call
+    and get result"  But the key point is that the user starts with the arc as a
+    CCDImage and ends with a wavelength solution.
+    """
+    def __call__(self, arcimage: CCDImage) -> WavelengthSolution:
+        raise NotImplementedError()
+        return solution
+
+class WavelengthSolution:
+    def __init__(self, tbd):
+        raise NotImplementedError()
+
+    def get_wcs(self):
+        raise NotImplementedError()
+
+    def apply_wcs(self, spectrum : Union([Spectrum1D, SpectrumCollection])):
+        spectrum.wcs = self.get_wcs()
+
+
+@dataclass
+class BoxcarExtract:
+    width : float  # pixels
+    trace : Union([astropy.modeling.models.Model1D, float])  # model maps x to y, float is syntactic sugar for a constant model
+    background_width: Union([float, None]) # None for no background subtraction
+    background_fit: astropy.modeling.models.Model1D = astropy.modeling.models.Linear1D # the line-by-line background to subtract
+
+    def __call__(self, spec2d: SpectrumCollection) -> Spectrum1D # note spec2d should already have the wavelength solution in it (see the workflow for how this could be acheived)
+        raise NotImplementedError()
+        return extracted_spectrum
+
+
+def basic_workflow():
+    rawframe = CCDImage.open(fn)
+
+    ccdproc = CCDProc() # whatever needs to happen here
+    processed_sci = ccdproc(rawframe)
+
+    ccdproc = CCDProc() # whatever needs to happen here
+    processed_arc = ccdproc(rawdata[idx_arc]
+
+    id2d = AutoIdentify2D(my_line_list_that_i_like)
+    wlsoln = id2d(processed_arc)
+
+    wlcal_spec = wlsoln.apply(SpectrumCollection([for row in processed_sci]))
+
+    bex = BoxcarExtract(width=10, trace=123*u.pixel, background_width=5)
+
+    spec1d = bex(wlcal_spec)  # 1d spectrum!