Add support for Google BigQuery

[aleDsz]

KinoDB.-.BigQuery.mp4

• Closes Allow drag and drop of credential.json for BigQuery #8
• Closes Provide a link to instructions to download credentials.json for Google BigQuery #9

[wojtekmach]

What happens if we get an error from google? e.g. there's a syntax error in the query which would probably result in a HTTP 400. I believe in that case ReqBigQuery would return a %Req.Response{status: 400, ...} but KinoDB cannot do anything with it. Should it raise a good error message?

Two things:

1. If we're missing an integration test for such invalid query in req_bigquery, please add one.
2. If we want a reasonable error message out of Req.Response, we can change Req.new to Req.new(http_errors: :raise).

[aleDsz]

I'll implement how to show the Google BigQuery help box with Service Account credentials JSON generation, so this PR isn't ready to merge yet.

[jonatanklosko]

🐱 !!

[aleDsz]

So the help box for Google BigQuery looks like this:

[jonatanklosko]

Awesome work!

[wojtekmach]

@aleDsz I believe we need to do one more change. If the user didn't select a credentials file, we should start Goth without the :source option so it can do the application default credential thing and if that fails, there is a good error message. Only if the user dropped credentials file, we'd explicitly set :source. WDYT?

[aleDsz]

@aleDsz I believe we need to do one more change. If the user didn't select a credentials file, we should start Goth without the :source option so it can do the application default credential thing and if that fails, there is a good error message. Only if the user dropped credentials file, we'd explicitly set :source. WDYT?

I agree, we should remove :source so the metadata or system env could be used by default 🚀