repoze.debug 0.3

Forensic debugging WSGI middleware

repoze.debug README

Middleware which can help with in-production forensic debugging.

Installation

Install using setuptools, e.g. (within a virtualenv):

$ easy_install repoze.debug

responselogger middleware

The responselogger middleware logs requests and responses to a file for later perusal.

Configuration via Python

Wire up the middleware in your application:

from repoze.debug.responselogger import ResponseLoggingMiddleware
from logging import getLogger
middleware = ResponseLoggingMiddleware(
               app,
               max_bodylen='3KB',
               logger=getLogger('foo')
              )

The configuration options are as follows:

- ``max_bodylen`` should be the size in bytes (optionally followed by
  KB, MB, or GB) of the response body that should be logged.

- ``logger`` is a PEP 282 logger instance (any).

Configuration via Paste

Wire the middleware into a pipeline in your Paste configuration, for example:

[filter:responselogger]
use = egg:repoze.debug#responselogger
filename = %(here)s/response.log
# if max_bodylen is unset or is 0, it means do not limit body logging
# default is 0
max_bodylen = 3KB
# if max_logsize is unset or is 0, it means do not limit logsize; default is
# 100MB
max_logsize = 100MB
# if backup_count is 0, do not rotate the logfile.  Default is 10.
backup_count = 10

...

[pipeline:main]
pipeline = egg:Paste#cgitb
           responselogger
           myapp

The middleware will log response data to filename.

Operation

Once the middleware is in the pipeline, it will log requests and responses to the logger. An example of the log output for a request follows:

--- REQUEST 860724193 at Fri Jun 13 18:40:47 2008 ---
URL: http://localhost:9971/p_/pl
CGI Variables
  ACTUAL_SERVER_PROTOCOL: HTTP/1.1
  AUTH_TYPE: Basic
  HTTP_ACCEPT: */*
  HTTP_ACCEPT_ENCODING: gzip, deflate
  HTTP_ACCEPT_LANGUAGE: en-us
  HTTP_CONNECTION: keep-alive
  HTTP_HOST: localhost:9971
  HTTP_REFERER: http://localhost:9971/manage_menu
  HTTP_USER_AGENT: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_2; en-us) AppleWebKit/525.18 (KHTML, like Gecko) Version/3.1.1 Safari/525.18
  PATH_INFO: /p_/pl
  REMOTE_ADDR: 127.0.0.1
  REMOTE_PORT: 51422
  REQUEST_METHOD: GET
  SERVER_NAME: vitaminf-2.local
  SERVER_PORT: 9971
  SERVER_PROTOCOL: HTTP/1.1
  SERVER_SOFTWARE: CherryPy/3.0.2 WSGI Server
WSGI Variables
  repoze.debug.request_begin: 1213396847.41
  wsgi process: Multithreaded
  repoze.debug.id: 860724193
  application: <paste.httpexceptions.HTTPExceptionHandler object at 0x17a8fd0>
--- end REQUEST 860724193 ---

Each request is tagged with a (random) identifier. A response is also written to the log, and can be matched up to the request that generated it via the identifier. Here’s an example of a response in the log:

--- RESPONSE 860724193 at Fri Jun 13 18:40:47 2008 (0.0083 seconds) ---
Status: 200 OK
Response Headers
  Cache-Control: public,max-age=60
  Content-Length: 872
  Content-Type: image/gif
  Last-Modified: Thu, 06 Mar 2008 17:25:30 GMT
Bodylen: 872
Body:

1?9p?:'~?? ?0a???q?J?(I?|;@@???????@?????!?,H? ?H?`?2t???K.LH?`D?
--- end RESPONSE 860724193 ---

canary middleware

The ‘canary’ middleware is middleware that helps you figure out if you are leaking WSGI environment dictionary objects.

Configuration via Python

Wire up the middleware in your application:

from repoze.debug.canary import CanaryMiddleware
middleware = CanaryMiddleware(app)

Configuration via Paste

Wire the canary middleware up into your pipeline:

[pipeline:main]
pipeline = egg:Paste#cgitb
           egg:repoze.debug#canary
           myapp

Usage

If refcounts to repoze.debug.canary.Canary grow without bound, you know you are leaking WSGI environment dictionaries. Use e.g. Dozer to find reference leaks.

Reporting Bugs / Development Versions

Visit http://bugs.repoze.org to report bugs. Visit http://svn.repoze.org to download development or tagged versions.

Next release

• Add ‘canary’ middleware for detecting environment dictionary leaks. Add to your Paste config via ‘egg:repoze.debug#canary’; it takes no arguments. If refcounts to repoze.debug.canary.Canary grow without bound, you know you are leaking WSGI environment dictionaries.

• Add source url to response logging.

0.2 (2008/06/14)

• Add warning if content-length != body length.

0.1 (2008/06/13)

• Initial release.