Print out response body when a 500 Internal Server Error is received from the pushgateway

I accidentally sent malformed data to a push gateway and got back a 500 Internal Server Error. The body of the response had information about the malformed data but all that was printed was the fact that I got a 500 Internal Server Error.

Example code:

import prometheus_client

reg = prometheus_client.CollectorRegistry()
c1 = prometheus_client.Counter("foo", "bar", labelnames=["baz", "stuff"], registry=reg)
c1.labels({"baz": 1, "stuff": 2}).inc(1)
c2 = prometheus_client.Counter("foo", "bar", labelnames=["baz", "stuff"], registry=reg)
c2.labels({"baz": 3, "stuff": 4}).inc(2)
prometheus_client.push_to_gateway('localhost:8000', job='example', registry=reg)

Output:

Traceback (most recent call last):
  File "test.py", line 8, in <module>
    prometheus_client.push_to_gateway('localhost:8000', job='example', registry=reg)
  File "/usr/local/lib/python2.7/dist-packages/prometheus_client/exposition.py", line 110, in push_to_gateway
    _use_gateway('PUT', gateway, job, registry, grouping_key, timeout)
  File "/usr/local/lib/python2.7/dist-packages/prometheus_client/exposition.py", line 144, in _use_gateway
    resp = build_opener(HTTPHandler).open(request, timeout=timeout)
  File "/usr/lib/python2.7/urllib2.py", line 437, in open
    response = meth(req, response)
  File "/usr/lib/python2.7/urllib2.py", line 550, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.7/urllib2.py", line 475, in error
    return self._call_chain(*args)
  File "/usr/lib/python2.7/urllib2.py", line 409, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 558, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
urllib2.HTTPError: HTTP Error 500: Internal Server Error

Bắt đầu trong prometheus_client/exposition.py, tại push_to_gateway và _use_gateway, sử dụng ví dụ malformed-data để tái hiện phản hồi HTTP 500. Kiểm tra cách lỗi phản hồi hiện được hiển thị và xác minh rằng lỗi push bao gồm phần nội dung phản hồi trong khi vẫn giữ nguyên các chi tiết lỗi hiện có.