client.compute() not properly working with "workers" and dask.array

Hi there,

client.compute() properly works with a delayed object and “workers” specified, but not with a dask array.

For an existing (distributed) client

from dask import delayed
from operator import add
x = delayed(add)(1, 2)
xx = client.compute([x],workers=['tcp://130.183.183.160:34655'])

is fine, but

import dask.array as da
y = da.random.random(10)
y = client.compute([y],workers=['tcp://130.183.183.160:34655'])

fails with:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/freya/u/cbyrohl/repos/voroILTIS/production_LAE_SBr/haloprofiles.py in <module>
      1 from dask import delayed
      2 y = da.random.random(10)
----> 3 y = client.compute([y],workers=['tcp://130.183.183.160:34655'])

~/anaconda3/envs/lya/lib/python3.7/site-packages/distributed/client.py in compute(self, collections, sync, optimize_graph, workers, allow_other_workers, resources, retries, priority, fifo_timeout, actors, traverse, **kwargs)
   2767 
   2768         restrictions, loose_restrictions = self.get_restrictions(
-> 2769             collections, workers, allow_other_workers
   2770         )
   2771 

~/anaconda3/envs/lya/lib/python3.7/site-packages/distributed/client.py in get_restrictions(cls, collections, workers, allow_other_workers)
   3814         """ Get restrictions from inputs to compute/persist """
   3815         if isinstance(workers, (str, tuple, list)):
-> 3816             workers = {tuple(collections): workers}
   3817         if isinstance(workers, dict):
   3818             restrictions = {}

TypeError: unhashable type: 'Array'

Easy workaround is to create a delayed object from the array, but I think client.compute() is supposed to work with all dask collections?

Thanks, Chris

[mrocklin]

Great. Thanks for checking @andrewfulton9 . Closing.

[jrbourbeau]

Closing as today one can specify which workers to compute a collection on using Dask’s annotation macheinery

xref https://github.com/dask/distributed/pull/4406