deb-python-pecan/docs/source/development.rst

Developing Pecan Applications Locally

Debugging Pecan Applications

Pecan comes with simple debugging middleware for helping diagnose problems in your applications. To enable the debugging middleware, simply set the debug flag to True in your configuration file:

app = {
    ...
    'debug': True,
    ...
}

Once enabled, the middleware will automatically catch exceptions raised by your application and display the Python stack trace and WSGI environment in your browser for easy debugging:

To further aid in debugging, the middleware includes the ability to repeat the offending request, automatically inserting a breakpoint, and dropping your console into the Python debugger, pdb.post_mortem:

You can also use any debugger with a suitable post_mortem entry point. For example, to use the PuDB Debugger, set debugger like so:

import pudb

app = {
    ...
    'debug': True,
    'debugger': pudb.post_mortem,
    ...
}

Refer to the pdb documentation for more information on using the Python debugger.

Serving Static Files

Pecan comes with simple file serving middleware for serving CSS, Javascript, images, and other static files. You can configure it by ensuring that the following options are specified in your configuration file:

app = {
    ...
    'debug': True,
    'static_root': '%(confdir)/public
}

where static_root is an absolute pathname to the directory in which your static files live. For convenience, the path may include the %(confdir) variable, which Pecan will substitute with the absolute path of your configuration file at runtime.

Note

In production, app.debug should never be set to True, so you'll need to serve your static files via your production web server.