Using `repoze.errorlog`¶

Overview¶

This package implements a WSGI middleware filter which intercepts exceptions and writes them to a Python logging module channel (or the wsgi.errors filehandle, if no channel is configured). It also allows the browsing of limited exception history via a browser UI.

Configuration¶

To use the default configuration, you can just include the filter in your application’s PasteDeploy pipeline, e.g.:

[pipeline:main]
pipeline = egg:Paste#cgitb
           egg:repoze.errorlog#errorlog
           yourapp

To override the default configuration, you need to make a separate section for the filter. The Paste configuration options at this time are channel, keep and path. To configure repoze.errorlog to use the Repoze logging channel, which sends to the logging channel as if you had send to a logger from code where you did from logging import getLogger; logger = getLogger("Repoze") and to keep 50 tracebacks around for through-the-web exception viewing, configure like so:

[filter:errorlog]
channel = Repoze
keep = 50
path = /__my_error_log__
ignore = RuntimeError my.module:MyError

By default, no channel is configured, and tracebacks are sent to the wsgi.errors file handle (which should cause the errors to show up in your server’s error log). By default, the exception history length (keep) is 20.

By default, the error log’s path is /__error_log__; you can change this as necessary for your deployment.

The ignore parameter prevents the exceptions named from being logged or kept in exception history (although they are reraised). By default, no exceptions are ignored.

To use the reconfigured filter in the pipeline:

[pipeline:main]
pipeline = egg:Paste#cgitb
           errorlog
           yourapp

If you don’t use PasteDeploy, you can configure the ErrorLog middleware manually:

app = ErrorLog(app, channel=None, keep=20, path='/__error_log__',
               ignored_exceptions=())

Viewing Recent Tracebacks¶

To view recent tracebacks via your browser (exception history), visit the /__error_log__ path at the hostname represented by your server. A view will be presented showing you all recent tracebacks. Clicking on one will bring you to a page which shows you the traceback and a rendering of the WSGI environment which was present at the time the exception occurred.

Integration¶

When repoze.errorlog is placed into the pipeline, two keys are placed into the wsgi environment on every request (even when an exception is not raised and caught by repoze.errorlog):

repoze.errorlog.path: the path at which the errorlog is configured
repoze.errorlog.entryid: the entry id of the next error

Middleware and applications that catch exceptions can compose a URL to the current error (for helpful development feedback) when they know repoze.errorlog` is in the pipeline by using the following code:

from paste.request import construct_url
path = environ['repoze.errorlog.path']
entry = environ['repoze.errorlog.entryid']
url = construct_url(environ, path_info=path,
                    querystring='entry=%s' % entry)

Reporting Bugs / Development Versions¶

Please report bugs at https://github.com/repoze/repoze.errorlog/issues . Check development version out from https://github.com/repoze/repoze.errorlog .

Using repoze.errorlog¶