Fixes kubernetes-client/python issue 1047 "ResponseNotChunked from watch"

[dhague]

In recent versions of K8S (>1.16?), when a Watch.stream() call uses a
resource_version which is too old the resulting 410 error is wrapped in JSON
and returned in a non-chunked 200 response. Using resp.stream() instead of
resp.read_chunked() automatically handles the response being either chunked or
non-chunked.

Fix watch stream non-chunked response handling 

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[dhague]

The build failure seems to be a flaky test unrelated to this PR, and has occurred in other commits on master

[yliaog]

please squash the commits

have you manually tested it in your env to verify the fix?

The documentation below says stream is a wrapper for read(), but does not mention read_chunked().

stream(amt=65536, decode_content=None)
A generator wrapper for the read() method.

[dhague]

1. Commits are now squashed

2. I have been testing this in my dev environment, and also in the CI pipeline for our app that uses the Python Kubernetes client. Some flaky tests in the CI pipeline are what led me to fixing this in the first place :-)

3. As to the stream() method itself, you can see from the implementation below that it deals explicitly with both read() and read_chunked() cases - it does exactly what we want:

    def stream(self, amt=2 ** 16, decode_content=None):
        """
        A generator wrapper for the read() method. A call will block until
        ``amt`` bytes have been read from the connection or until the
        connection is closed.

        :param amt:
            How much of the content to read. The generator will return up to
            much data per iteration, but may return less. This is particularly
            likely when using compressed data. However, the empty string will
            never be returned.

        :param decode_content:
            If True, will attempt to decode the body based on the
            'content-encoding' header.
        """
        if self.chunked and self.supports_chunked_reads():
            for line in self.read_chunked(amt, decode_content=decode_content):
                yield line
        else:
            while not is_fp_closed(self._fp):
                data = self.read(amt=amt, decode_content=decode_content)

                if data:
                    yield data

[yliaog]

thanks for pr

/lgtm
/approve

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This pull-request has been approved by: dhague, yliaog

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