Improper status code handling between flask and wsgi instrumentation: bare status codes.

[tmc]

Flask's Response type status field can be just a simple string or an integer but the wsgi instrumentation here expects it to be able to be split on a string (understandable as that's wsgi / pep 3333 compliant).

This line

opentelemetry-python-contrib/instrumentation/opentelemetry-instrumentation-flask/src/opentelemetry/instrumentation/flask/__init__.py

Lines 107 to 110 in 753e228

	if span:
	otel_wsgi.add_response_attributes(
	span, status, response_headers
	)

Can blow up in this manner:

  File "/usr/local/lib/python/dist-packages/flask/app.py", line 2453, in wsgi_app
    return response(environ, start_response)
  File "/usr/local/lib/python/dist-packages/werkzeug/wrappers/base_response.py", line 701, in __call__
    start_response(status, headers)
  File "/usr/local/lib/python/dist-packages/opentelemetry/instrumentation/flask/__init__.py", line 109, in _start_response
    span, status, response_headers
  File "/usr/local/lib/python/dist-packages/opentelemetry/instrumentation/wsgi/__init__.py", line 163, in add_response_attributes
    status_code, _ = start_response_status.split(" ", 1)
ValueError: not enough values to unpack (expected 2, got 1)

[srikanthccv]

When does this happen? I don't see when the status received in start_response is an integer. I tried to take a quick look at werkzeug and it looks to me this shouldn't happen https://github.com/pallets/werkzeug/blob/f7b53ee8a81f015c6c85659959004328237a3c8c/src/werkzeug/middleware/http_proxy.py#L194-L201.

[github-actions]

This issue was marked stale due to lack of activity. It will be closed in 30 days.

[max-okumoto]

Hi. I ran into the same problem, but I have more information. If the return status of the handler is a "string", the traceback is hit. But if I send an integer number, there is no traceback.

@app.route("/readytoserve")
def hc():
return "GOOD", "200" <--- causes same traceback

@app.route("/readytoserve")
def hc():
return "GOOD", 200. <--- does not trigger