cannot write mode P as JPEG

[ayleph]

A user tried to upload an image which produced the following error. A stackoverflow thread mentions converting to RGB space.

​https://stackoverflow.com/questions/21669657/getting-cannot-write-mode-p-as-jpeg-while-operating-on-jpg-image

(mediagoblin-0.8.0) ~/mediagoblin $ bin/gmg reprocess run 4028 initial
DEBUG:mediagoblin.processing.task:Processing <MediaEntry 4028: otters>
ERROR:mediagoblin.processing.task:An unhandled exception was raised while processing <MediaEntry 4028: otters>
WARNING:mediagoblin.processing:No idea what happened here, but it failed: IOError('cannot write mode P as JPEG',)
WARNING:mediagoblin.processing:No idea what happened here, but it failed: IOError('cannot write mode P as JPEG',)
Traceback (most recent call last):
  File "bin/gmg", line 9, in <module>
    load_entry_point('mediagoblin==0.8.1.dev0', 'console_scripts', 'gmg')()
  File "/path/to/mediagoblin/mediagoblin/gmg_commands/__init__.py", line 142, in main_cli
    args.func(args)
  File "/path/to/mediagoblin/mediagoblin/gmg_commands/reprocess.py", line 293, in reprocess
    run(args)
  File "/path/to/mediagoblin/mediagoblin/gmg_commands/reprocess.py", line 205, in run
    reprocess_info=reprocess_request)
  File "/path/to/mediagoblin/mediagoblin/submit/lib.py", line 257, in run_process_media
    task_id=entry.queued_task_id)
  File "/path/to/mediagoblin/lib/python2.7/site-packages/celery-3.1.17-py2.7.egg/celery/app/task.py", line 547, in apply_async
    link=link, link_error=link_error, **options)
  File "/path/to/mediagoblin/lib/python2.7/site-packages/celery-3.1.17-py2.7.egg/celery/app/task.py", line 739, in apply
    request=request, propagate=throw)
  File "/path/to/mediagoblin/lib/python2.7/site-packages/celery-3.1.17-py2.7.egg/celery/app/trace.py", line 355, in eager_trace_task
    uuid, args, kwargs, request)
  File "/path/to/mediagoblin/lib/python2.7/site-packages/celery-3.1.17-py2.7.egg/celery/app/trace.py", line 253, in trace_task
    I, R, state, retval = on_error(task_request, exc, uuid)
  File "/path/to/mediagoblin/lib/python2.7/site-packages/celery-3.1.17-py2.7.egg/celery/app/trace.py", line 240, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/path/to/mediagoblin/mediagoblin/processing/task.py", line 101, in run
    processor.process(**reprocess_info)
  File "/path/to/mediagoblin/mediagoblin/media_types/image/processing.py", line 318, in process
    self.generate_thumb(size=thumb_size, filter=filter, quality=quality)
  File "/path/to/mediagoblin/mediagoblin/media_types/image/processing.py", line 221, in generate_thumb
    filter, size)
  File "/path/to/mediagoblin/mediagoblin/media_types/image/processing.py", line 125, in resize_tool
    quality, filter)
  File "/path/to/mediagoblin/mediagoblin/media_types/image/processing.py", line 81, in resize_image
    resized.save(resized_file, quality=quality)
  File "/path/to/mediagoblin/lib/python2.7/site-packages/PIL/Image.py", line 1682, in save
    save_handler(self, fp, filename)
  File "/path/to/mediagoblin/lib/python2.7/site-packages/PIL/JpegImagePlugin.py", line 571, in _save
    raise IOError("cannot write mode %s as JPEG" % im.mode)
IOError: cannot write mode P as JPEG

[ayleph]

Changing priority as I only saw this issue once.

[Loic Dachary]

Unless steps to reproduce the problem are added to this issue, it should probably be closed.

[Ben Sturmfels]

I've spent some time trying to reproduce this issue, but no luck. I've tried various images including one with Adobe RGB colour space (as opposed to the more common sRGB).

I was able to make processing fail with a 1200x900 indexed PNG file (ie. one that needed resizing), but it didn't fail as above, so I'll create a separate ticket. Error was "OSError: cannot identify image file", re-raised as a BadMediaFail exception.

As Loic suggests, I'll close this as we can't reproduce it at this stage. Would love to hear if anyone comes up with an example that triggers this.

[ayleph]

Okay with me. If I run across this again, I'll grab the image that causes it and share that in the ticket.

[ayleph]

This just happened again. In this case it's a .gif that was named .gif.jpg prior to being uploaded. I'll attach it here.

[Ben Sturmfels]

This is related to #5444. I'm starting to wonder whether filename should be used at all and whether it would be more robust to rely completely on sniffing.