Dozer 0.9

Tracking down memory leaks

Usage:

from dozer import Dozer

# my_wsgi_app is a WSGI application
wsgi_app = Dozer(my_wsgi_app)

Assuming you’re serving your application on the localhost at port 5000, you can then load up http://localhost:5000/_dozer/index to view the gc info.

Profiling requests

Usage:

from tempfile import mkdtemp
from dozer import Profiler

# my_wsgi_app is a WSGI application
wsgi_app = Profiler(my_wsgi_app, profile_path=mkdtemp(prefix='dozer-'))

Assuming you’re serving your application on the localhost at port 5000, you can then load up http://localhost:5000/_profiler to view the list of recorded request profiles.

The profiles are stored in the directory specified via profile_path. If you want to keep seeing older profiles after restarting the web app, specify a fixed directory instead of generating a fresh empty new one with tempfile.mkdtemp. Make sure the directory is not world-writable, as the profiles are stored as insecure Python pickles, which allow arbitrary command execution during load.

Here’s a blog post by Marius Gedminas that contains a longer description of Dozer’s profiler.

Inspecting log messages

Usage:

from dozer import Logview

# my_wsgi_app is a WSGI application
wsgi_app = Logview(my_wsgi_app)

Every text/html page served by your application will get some HTML and Javascript injected into the response body listing all logging messages produced by the thread that generated this response.

Here’s a blog post by Marius Gedminas that contains a longer description of Dozer’s logview.

0.9 (November 7, 2025)

• Add support for Python 3.10, 3.11, 3.12, 3.13, and 3.14.

• Drop support for Python 2.7, 3.6, 3.7, 3.8, and 3.9.

• Stop using the cgi module (which wasn’t really being used).

• Possibly fix a bug where unbound methods were not being filtered out properly in memory leak reports.

0.8 (November 13, 2020)

• Add support for Python 3.8 and 3.9.

• Drop support for Python 3.5.

• Add UI input for existing “floor” query string parameter (https://github.com/mgedmin/dozer/issues/2)

• Add UI input to filter type charts by a regular expression

• Add sorting option: monotonicity

• Display traceback on 500 Internal Server Error

• Dicts and sets with unsortable keys are no longer unrepresentable

• Aggregate dynamically-created types with the same __name__ and __module__ (issue 9).

0.7 (April 23, 2019)

• Add support for Python 3.7.

• Drop support for Python 3.3 and 3.4.

• Stop using cgi.escape on Python 3, which is especially important now that it’s been removed from Python 3.8.

0.6 (May 18, 2017)

• Add support for Python 3.6.

• Drop support for Python 2.6.

• Fix rare TypeError when listing profiles, if two profiles happen to have the exact same timestamp (https://github.com/mgedmin/dozer/pull/4).

0.5 (December 2, 2015)

• Make /_dozer show the index page (instead of an internal server error).

• Add support for Python 3.4 and 3.5.

• Drop support for Python 2.5.

• Move to GitHub.

0.4 (March 21, 2013)

• 100% test coverage.

• Add support for Python 3.2 or newer.

• Drop dependency on Paste.

0.3.2 (February 10, 2013)

• More comprehensive fixes for issue #5 by Mitchell Peabody.

• Fix TypeError: unsupported operand type(s) for +: ‘property’ and ‘str’ (https://bitbucket.org/bbangert/dozer/issue/3).

• Add a small test suite.

0.3.1 (February 6, 2013)

• Fix TypeError: You cannot set Response.body to a text object (https://bitbucket.org/bbangert/dozer/issue/5). Patch by Mitchell Peabody.

0.3 (December 13, 2012)

• Emit the “PIL is not installed” only if the Dozer middleware is actually used.

• Give a name to the Dozer memleak thread.

• You can now supply a function directly to Logview(stack_formatter=fn)

• New configuration option for Logview middleware: tb_formatter, similar to stack_formatter, but for exception tracebacks.

0.2 (December 5, 2012)

• Adding logview that appends log events for the current request to the bottom of the html output for html requests.

• Adding profiler for request profiling and call tree viewing.

• Refactored Dozer into its own leak package.

• New maintainer: Marius Gedminas.

0.1 (June 14, 2008)

• Initial public release, port from Dowser, a CherryPy tool.