Google-cloud-python: Automagically convert dicts to datastore entities.

[remcohaszing]

I just ran into the following error for the X'th time:

    client.put(entity)
  File "lib/python3.6/site-packages/google/cloud/datastore/client.py", line 384, in put
    self.put_multi(entities=[entity])
  File "lib/python3.6/site-packages/google/cloud/datastore/client.py", line 408, in put_multi
    current.put(entity)
  File "lib/python3.6/site-packages/google/cloud/datastore/batch.py", line 199, in put
    _assign_entity_to_pb(entity_pb, entity)
  File "lib/python3.6/site-packages/google/cloud/datastore/batch.py", line 319, in _assign_entity_to_pb
    bare_entity_pb = helpers.entity_to_protobuf(entity)
  File "lib/python3.6/site-packages/google/cloud/datastore/helpers.py", line 219, in entity_to_protobuf
    _set_protobuf_value(value_pb, value)
  File "lib/python3.6/site-packages/google/cloud/datastore/helpers.py", line 420, in _set_protobuf_value
    _set_protobuf_value(i_pb, item)
  File "lib/python3.6/site-packages/google/cloud/datastore/helpers.py", line 408, in _set_protobuf_value
    attr, val = _pb_attr_value(val)
  File "lib/python3.6/site-packages/google/cloud/datastore/helpers.py", line 325, in _pb_attr_value
    raise ValueError("Unknown protobuf attr type %s" % type(val))
ValueError: Unknown protobuf attr type <class 'dict'>

The cause is pretty obvious, the following code snippet triggers this error:

entity = datastore.Entity(client.key('Resource'))
entity.update(foo={'bar': 'baz'})
client.put(entity)

The code crashes, because dict type properties are not supported. Instead they should be converted to an Entity.

I think it's cumbersome having to convert dict types to Entity types every time. I've written a function that does the conversion recursively for production code, but for simple scripts this is still an issue.

I think it would be nice if this library would just do the conversion from dict to Entity automagically.

[dhermes]

@remcohaszing It's definitely worth considering! Thanks for filing.

@lukesneeringer @jonparrott WDYT?

[lukesneeringer]

I am supportive.

[dhermes]

Working on it now. Hopefully it'll be quick.

[sd-omkar]

@dhermes thanks for the patch in https://github.com/GoogleCloudPlatform/google-cloud-python/pull/3927.

I was wondering how long would it take for this change to make it to https://pypi.org/project/google-cloud/. The latest there seems to be from Aug. 5, 2017

[dhermes]

@sd-omkar Thanks for noticing, we'll try to get a release out soon.

Also, worth noting that the google-cloud package is less relevant than the google-cloud-datastore package.