by Andrew Dalke for EuroPython 2012
The future is here! Or rather, concurrent.futures became part of the Python standard library with 3.2. This style of asynchronous programming, also known as promises, has been around for decades but is only recently becoming popular in a number of languages and libraries.
My presentation is meant for a Python programmer who knows nothing about futures. I’ll structure it around processing web server logs, and show several ways to Python code can make more effective use of a multi-core machine. In some cases the multi-threaded executor is good enough, but in others the right solution is the multi-process executor. Because of the unified API, it’s a one line change to switch from one to the other.
It isn’t hard to write your own executor for different compute models. I’ll show that by developing a new one which works on top of the PiCloud API. At the end I’ll describe some of the more experimental work I’m doing to use promises in a dependency graph, where certain computed properties are dependent on others.
Even though concurrent.futures came in 3.2, Python 2.x users can use the API through Alex Grönholm’s ‘futures’ backport.