I'm going to make a pie chart to show web access by browser. I want to use httpagentparser (module)
to python lookup cool name of browser.
Is this best practice?
In general, yes. Get your data into splunk, then use something like you suggested to find out the browser and have some fun.
As a next step you could always try the Splunk App for Web Analytics. It is a bit more work but the payoff is also great.