Correctly parse labels if they are passed as a single string instead of a list

[damccorm]

Right now, if you submit a job like:

options = PipelineOptions()
options.view_as(StandardOptions).runner = "DataflowRunner"
<other options>
options.view_as(GoogleCloudOptions).labels = {'env': 'bluecore-qa-extensibility', 'team': 'cdp-vertical'}

with beam.Pipeline(options=options) as p:
  <do stuff>

The job does not correctly recognize the labels. We could validate and fail because labels is expected to be a list, but that might break existing (mostly working) pipelines. This is an in between where we can still do a best effort to correctly identify/use the user's labels.

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[liferoad]

do you mean options.view_as(GoogleCloudOptions).labels = {'env': 'bluecore-qa-extensibility', 'team': 'cdp-vertical'} is interpreted as a string although it is a Python dict?

[damccorm]

Whoops, meant to make this a draft until I full tested it. But you're right, this won't fully work yet. I think I'll also want something like:

if not isinstance(labels, Iterable):
   labels = [str(labels)]

But I'll fix/test this with the string and dict cases

[damccorm]

This should now handle both cases, and I added some representative test cases, PTAL

[damccorm]

R: @liferoad

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