Joe Gregorio originally posted about Sharded Counters for Google Appengine.

This is like a downloadable gist:

from sharc import Counter

assert not Counter('A').exists()

Counter('A', initial_value=5, shards=5)
assert Counter('A').exists()

Counter('A').increment()
Counter('A').decrement()
Counter('A') + 2
Counter('A') - 2

assert Counter('A') == 5

Counter('A').shards = 10

Counter('A').delete()   # .delete_async()
assert not Counter('A').exists()

• Added decrement
• Increment and decrement variable deltas (default=1)
• Set initial value of the counter (default=0)
• Set initial value of the num of shards (default=20)
• Added delete()