Logs / errors are lost due to wsgi.errors not extracted

[pupssman]

Hey there and thanks for a fancy tool!

I've noticed that interceptor puts a io.BytestIO to wsgi.errors.
That causes some trouble:

• it is never read -- so logs from my flask app crashes are lost
• flask attempts to write a unicode there and fails with

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/logging/__init__.py", line 882, in emit
    stream.write(fs % msg)
TypeError: 'unicode' does not have the buffer interface
Logged from file app.py, line 1560

IMO putting a sys.stderr there would actually improve the situation.

If it is a viable option I can go ahead and produce a pull request.

[cdent]

Thanks for the report. I'll need to investigate the history of why wsgi.errors is set to that. sys.stderr may very well be the right thing, but I'll need to do some remembering first. If it proves to be the right thing a pull request would be great.

If you have a minimal test case that demonstrates the problem that you can share that would be great.

[cdent]

The use of BytesIO pre-dates my maintenance of wsgi-intercept and its migration to become simpler and support Python 3. So I can't find any history as to why it is that, other than "it's a good way to swallow stuff".

Setting it to sys.stderr looks like the right thing to do, especially given pep 3333's implication that that it is the norm.

So if you have the time to make a pull request that would be great and I'll get it merged and released asap.

[pupssman]

Here is the MVE:

import flask
import requests

from wsgi_intercept.interceptor import RequestsInterceptor


app = flask.Flask(__name__)


@app.route('/')
def foo():
    # cause a KeyError
    return flask.jsonify({}['foo'])


def test_foo():
    with RequestsInterceptor(lambda: app, host='foo.com', port=80) as url:
        r = requests.get(url)

        assert r.status_code == 200

Running it causes the error:

(py27) pupssman@pupssman-ub:~/git/wsgi_interseptor_51_mve $ py.test test.py 
===================================================================================================================================================== test session starts =====================================================================================================================================================
platform linux2 -- Python 2.7.12, pytest-2.9.0, py-1.4.34, pluggy-0.3.1
rootdir: /home/pupssman/git/wsgi_interseptor_51_mve, inifile: 
collected 1 items 

test.py F

========================================================================================================================================================== FAILURES ===========================================================================================================================================================
__________________________________________________________________________________________________________________________________________________________ test_foo ___________________________________________________________________________________________________________________________________________________________

    def test_foo():
        with RequestsInterceptor(lambda: app, host='foo.com', port=80) as url:
            r = requests.get(url)
    
>           assert r.status_code == 200
E           assert 500 == 200
E            +  where 500 = <Response [500]>.status_code

test.py:20: AssertionError
---------------------------------------------------------------------------------------------------------------------------------------------------- Captured stderr call -----------------------------------------------------------------------------------------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python2.7/logging/__init__.py", line 882, in emit
    stream.write(fs % msg)
TypeError: 'unicode' does not have the buffer interface
Logged from file app.py, line 1560
================================================================================================================================================== 1 failed in 0.12 seconds ===================================================================================================================================================
(py27) pupssman@pupssman-ub:~/git/wsgi_interseptor_51_mve $ 

[pupssman]

Will go on with PR soon!