What is the Python equivalent of Tomcat?
There are different approaches which have one thing in common: They usually communicate via WSGI with their "container" (the server receiving the HTTP requests before they go to your Python code).
There are various containers:
- wsgiref - a very simple reference implementation which is nice during development
- Apache with mod_wsgi
- most other Webservers with a module adding WSGI support
- many more
when I think of making a basic web-app, I think of writing some servlets, building a WAR file, and deploying it in Tomcat or another servlet container.
That's nice, but irrelevant. That's just a Java-ism, and doesn't apply very widely outside Java.
In Python, suppose I wrote some code that was capable of responding to HTTP requests, what would I do with it? How would I deploy it?
That depends.
What is the most commonly used container in Python?
There isn't one.
And is there an equivalent of a WAR file, a standard packaging of a web-app into one file that works in the various containers?
There isn't one.
HTTP is a protocol for producing a response to a request. That's it. It's really a very small thing.
You have CGI scripts which can respond to a request. The Python cgi library can do that. http://docs.python.org/library/cgi.html.
This is relatively inefficient because the simple CGI rule is "fire off a new process for each request." It can also be insecure if the script allows elevated privileges or badly planned-out uploads.
You have the mod_wsgi framework to connect Apache to Python. This can behave like CGI, or it can have a dedicated Python "daemon" running at the end of a named pipe.
The WSGI standard defines a format for request and response processing that's very handy and very extensible. Most of the frameworks -- in one way or another -- are WSGI compatible.
Finally, there are more complete frameworks that include class definitions for requests and responses, URL parsing, Authentication, Authorization, etc., etc.
Here's a list: http://wiki.python.org/moin/WebFrameworks