[Web-SIG] PEAK now provides various WSGI gateway and server options

[Phillip J. Eby]

The CVS version of PEAK now offers three options for running WSGI 
applications: CGI, FastCGI, and SimpleHTTPServer.  For example, this command:

     peak launch WSGI import:my_app.application

will do this:

  1. Import 'application' from 'my_app', treating it as a WSGI application
  2. Start a SimpleHTTPServer listening to an arbitrary port on 'localhost'
  3. launch a browser window pointing to that local server

So, it's a pretty easy way to test and play with WSGI applications without 
needing to configure a web server or mess with CGI.

PEAK also includes a CGI/FastCGI gateway that auto-detects whether it's 
running under CGI or FastCGI; the equivalent command is:

     peak CGI WSGI import:my_app.application

But you would normally turn this into a shell script, e.g.:

    #!/bin/sh
    peak CGI WSGI import:my_app.application

that would then be used as the CGI or FastCGI application executable.

Finally, PEAK also offers an advanced FastCGI "supervisor" that's a 
compelling replacement for mod_fastcgi's process manager when running 
high-volume and slow-starting applications.  It handles its own forking and 
killing off of child processes when they become too idle, and it has better 
"knowledge" of when new processes should or shouldn't be started.

All of these containers are fairly stable, with some of them having been 
used in production for over a year now.  (Until now, of course, the 
interface they used was a predecessor of the current WSGI spec, and they 
now use a simple adapter (courtesy of the wsgiref library) to wrap 
WSGI-compliant objects such that they implement that older, more CGI-like 
interface.)

In addition to these server and gateway implementations, all of PEAK's 
web-based tools including the peak.web application framework, the 'DDT' 
(Document-Driven Testing) toolkit, and various example applications, are 
now all WSGI applications, and should in principle be able to run under 
other WSGI-compliant servers and gateways, once you write an appropriate 
startup script to instantiate them.

Information about PEAK can be found at 
http://peak.telecommunity.com/.  PEAK's server and gateway implementations 
are based on the 'wsgiref' library, which is distributed bundled with PEAK, 
as well as in a separate distribution.