Implement duo cache clean

[darsain]

Duo caches resolved tags in os.tmpdir() . '/duo', but doesn't provide an API to clean that when necessary.

Did some tagging shenanigans today and couldn't figure out why duo was resolving version to an old commit, as there was no mention of any caching happening in docs, nor any cleaning command to suggest something like that is in duo, so I've spend quite some time looking in another direction while debugging the issue. Damn it :)

[stephenmathieson]

thoughts on a duo-clear-cache command?

could be something as simple as:

#!/usr/bin/env node
var rm = require('rimraf').sync
var os = require('os')
var path = require('path')

var cache = path.join(os.tmpdir(), 'duo')

rm(cache)

[matthewmueller]

i'm +1, given that the caching issues still haven't been resolved.

[stephenmathieson]

cool, i'll put something together soonish

[dominicbarnes]

In case it wasn't obvious, this script should also destroy components/duo.json.

Also, should we follow node's convention and use duo cache clean ?