Add BigQuery UDF support

[takbab]

Add a field to support BigQuery UDF.
https://cloud.google.com/bigquery/docs/reference/v2/jobs

• configuration.query.userDefinedFunctionResources[]
• configuration.query.userDefinedFunctionResources[].inlineCode
• configuration.query.userDefinedFunctionResources[].resourceUri

(migrated from #1988)

[tseaver]

@takbab I think @dhermes was talking about dropping the use of _TypedProperty in favor of a property implementation which enforces that items in the list are suitable. If we use your class for the items in the list, then the property implementation would look something like:

@propertydefudf_resources(self):
"""List of user-defined resources. :rtype: list of :class:`UdfResource` :returns: the list, if set, or None """returnlist(self._udf_resources) ifself._udf_resourceselseNone@udf_resources.setterdefudf_resources(self, value):
"""Update list of user-defined resources :type value: list of :class:`UdfResource` :param value: the new list :raises: ValueError, ir the items in the list are not all instances of :class:`UdfResource` """ifnotall((isinstance(item, UdfResource) foriteminvalue)):
raiseValueError("pass a list of UdfResource instances")
self._udf_resources=tuple(value)

[tseaver]

See #2015 for an alternative.

[dwmclary]

#2015 looks a more like the example from @tseaver but I need to clean up a lint error. What's the advantage to the approach here?

[takbab]

@tseaver Thanks for the example! I have added the property to QueryJob class.

What can we do?
I just want to use UDF from my app.
#1829

[tseaver]

@takbab Thanks again for the patch! I merged @dwmclary's version of the feature in #2029, as it looked closer to what I had in mind.

[takbab]

I see, thanks!