Adding applications dynamically

NOTE: this is not the best approach for hosting multiple applications. You’d better to run a uWSGI instance for each app.

You can start the uWSGI server without configuring an application.

To load a new application you can use these variables in the uwsgi packet:

• UWSGI_SCRIPT – pass the name of a WSGI script defining an application callable

• or UWSGI_MODULE and UWSGI_CALLABLE – the module name (importable path) and the name of the callable to invoke from that module

Dynamic apps are officially supported on Cherokee, Nginx, Apache, cgi_dynamic. They are easily addable to the Tomcat and Twisted handlers.

Defining VirtualEnv with dynamic apps

Virtualenvs are based on the Py_SetPythonHome() function. This function has effect only if called before Py_Initialize() so it can’t be used with dynamic apps.

To define a VirtualEnv with DynamicApps, a hack is the only solution.

First you have to tell python to not import the site module. This module adds all site-packages to sys.path. To emulate virtualenvs, we must load the site module only after subinterpreter initialization. Skipping the first import site, we can now simply set sys.prefix and sys.exec_prefix on dynamic app loading and call

PyImport_ImportModule("site");
// Some users would want to not disable initial site module loading, so the site module must be reloaded:
PyImport_ReloadModule(site_module);

Now we can set the VirtualEnv dynamically using the UWSGI_PYHOME var:

location / {
  uwsgi_pass 192.168.173.5:3031;
  include uwsgi_params;
  uwsgi_param UWSGI_SCRIPT mytrac;
  uwsgi_param UWSGI_PYHOME /Users/roberto/uwsgi/VENV2;
}