setup.py: devtarget command to symlink src into target

[manics]

Recreate "target" with symlinks to files in "src" to ease development
For example, pip install -e . will work

Currently if you edit a file under src you must reinstall the python module. If isntead you fisrt run python setup.py devtarget this will symlink files from src into target instead of the default copy, which means you can use pip install -e . to install the module as an editable module as long as you only edit existing files. If you add/remove files under src you will need to rerun these commands. Default beahaviour should be unchanged.

[joshmoore]

Traceback (most recent call last):
  File "setup.py", line 213, in <module>
    'devtarget': DevTargetCommand,
  File "/opt/anaconda/lib/python2.7/site-packages/setuptools/__init__.py", line 143, in setup
    return distutils.core.setup(**attrs)
  File "/opt/anaconda/lib/python2.7/distutils/core.py", line 151, in setup
    dist.run_commands()
  File "/opt/anaconda/lib/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/opt/anaconda/lib/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "setup.py", line 151, in run
    copy_src_to_target(symlink=True)
  File "setup.py", line 118, in copy_src_to_target
    _relative_symlink_file(fromfile, tofile)
  File "setup.py", line 104, in _relative_symlink_file
    except FileExistsError:
NameError: global name 'FileExistsError' is not defined

[manics]

Should be fixed for Python 2.7 and 3.6 now

[joshmoore]

with devtarget ✅

/opt/omero-py/target $ls -ltra
lrwxr-xr-x    1 jamoore  wheel      34 Oct 21 14:44 omero_model_TemperatureI.py -> ../src/omero_model_TemperatureI.py
lrwxr-xr-x    1 jamoore  wheel      40 Oct 21 14:44 omero_model_ElectricPotentialI.py -> ../src/omero_model_ElectricPotentialI.py
lrwxr-xr-x    1 jamoore  wheel      30 Oct 21 14:44 omero_model_DetailsI.py -> ../src/omero_model_DetailsI.py
lrwxr-xr-x    1 jamoore  wheel      34 Oct 21 14:44 omero_model_PermissionsI.py -> ../src/omero_model_PermissionsI.py
lrwxr-xr-x    1 jamoore  wheel      19 Oct 21 14:44 runTables.py -> ../src/runTables.py
lrwxr-xr-x    1 jamoore  wheel      30 Oct 21 14:44 omero_model_UnitBase.py -> ../src/omero_model_UnitBase.py
lrwxr-xr-x    1 jamoore  wheel      21 Oct 21 14:44 shellserver.py -> ../src/shellserver.py
lrwxr-xr-x    1 jamoore  wheel      15 Oct 21 14:44 path.pyc -> ../src/path.pyc
lrwxr-xr-x    1 jamoore  wheel      22 Oct 21 14:44 runProcessor.py -> ../src/runProcessor.py
lrwxr-xr-x    1 jamoore  wheel      19 Oct 21 14:44 IceImport.py -> ../src/IceImport.py
lrwxr-xr-x    1 jamoore  wheel      23 Oct 21 14:44 omero_version.py -> ../src/omero_version.py
lrwxr-xr-x    1 jamoore  wheel      28 Oct 21 14:44 omero_model_PowerI.py -> ../src/omero_model_PowerI.py
lrwxr-xr-x    1 jamoore  wheel      31 Oct 21 14:44 omero_model_PressureI.py -> ../src/omero_model_PressureI.py
lrwxr-xr-x    1 jamoore  wheel      24 Oct 21 14:44 omero_version.pyc -> ../src/omero_version.pyc
lrwxr-xr-x    1 jamoore  wheel      31 Oct 21 14:44 omero_sys_ParametersI.py -> ../src/omero_sys_ParametersI.py
lrwxr-xr-x    1 jamoore  wheel      21 Oct 21 14:44 omero_setup.py -> ../src/omero_setup.py
lrwxr-xr-x    1 jamoore  wheel      29 Oct 21 14:44 omero_model_LengthI.py -> ../src/omero_model_LengthI.py
lrwxr-xr-x    1 jamoore  wheel      28 Oct 21 14:44 .omero_version.py.un~ -> ../src/.omero_version.py.un~
lrwxr-xr-x    1 jamoore  wheel      14 Oct 21 14:44 path.py -> ../src/path.py
lrwxr-xr-x    1 jamoore  wheel      32 Oct 21 14:44 omero_model_FrequencyI.py -> ../src/omero_model_FrequencyI.py
lrwxr-xr-x    1 jamoore  wheel      27 Oct 21 14:44 omero_model_TimeI.py -> ../src/omero_model_TimeI.py
drwxr-xr-x  428 jamoore  wheel   13696 Oct 21 14:44 .
drwxr-xr-x   16 jamoore  wheel     512 Oct 21 14:44 omero_ext
drwxr-xr-x   40 jamoore  wheel    1280 Oct 21 14:44 omero

and without ✅

-rw-r--r--    1 jamoore  wheel    7637 Oct 21 14:46 omero_model_PermissionsI.py
-rw-r--r--    1 jamoore  wheel    1264 Oct 21 14:46 runTables.py
-rw-r--r--    1 jamoore  wheel    1169 Oct 21 14:46 omero_model_UnitBase.py
-rwxr-xr-x    1 jamoore  wheel    3336 Oct 21 14:46 shellserver.py
-rw-r--r--    1 jamoore  wheel   50551 Oct 21 14:46 path.pyc
-rw-r--r--    1 jamoore  wheel     432 Oct 21 14:46 runProcessor.py
-rw-r--r--    1 jamoore  wheel     441 Oct 21 14:46 IceImport.py
-rw-r--r--    1 jamoore  wheel      75 Oct 21 14:46 omero_version.py
-rw-r--r--    1 jamoore  wheel   53603 Oct 21 14:46 omero_model_PowerI.py
-rw-r--r--    1 jamoore  wheel  135289 Oct 21 14:46 omero_model_PressureI.py
-rw-r--r--    1 jamoore  wheel   10251 Oct 21 14:46 omero_sys_ParametersI.py
-rwxr-xr-x    1 jamoore  wheel    3260 Oct 21 14:46 omero_setup.py
-rw-r--r--    1 jamoore  wheel  131835 Oct 21 14:46 omero_model_LengthI.py
-rw-r--r--    1 jamoore  wheel    4589 Oct 21 14:46 .omero_version.py.un~
-rw-r--r--    1 jamoore  wheel   51114 Oct 21 14:46 path.py
-rw-r--r--    1 jamoore  wheel   58317 Oct 21 14:46 omero_model_FrequencyI.py
-rw-r--r--    1 jamoore  wheel   70734 Oct 21 14:46 omero_model_TimeI.py

(Tested on Python 2.7.13)

Waiting on travis, but then I'd say let's get this in. Might be time to start collecting the dev workflow directly in the README.