Python feature flagging
Inspired by the rollout Ruby gem by James Golick and a Python port of it called proclaim by [Curt Micol](Curt Micol) which I found after reading Using Feature Flags to Ship Changes with Confidence by Mathias Meyer.
Both of these use redis, and I don't like that requirement. I seek to support multiple storage/persistence mechanisms.
To initialize pyrollout with the default in-memory feature & user storage:
import pyrollout
rollout = pyrollout.Rollout()Now add features:
from pyrollout.feature import Feature
# Open to all by using the special group 'ALL'
rollout.add_feature(Feature('feature_for_all', groups=['ALL']))
# Open to select groups
rollout.add_feature(Feature('feature_for_groups', groups=['vip', 'early_adopter]))
# Open to specific user(s), by user ID
rollout.add_feature(Feature('feature_for_users', users=[123, 456, 789]))
# Open to 20% of users, calculated via user ID
rollout.add_feature(Feature('20pct', percentage=20))Check access to features:
def untested_feature(user):
# Because this feature was not defined, access will always be denied (by default)
if not rollout.can(user, 'use_untested_feature'):
return None
else:
do_cool_things()
class FooHandler(BaseHandler):
def get(self):
# self.user is a user object in a format pyrollout understands
if not rollout.can(self.user, 'feature_for_users'):
self.abort(403)
else:
do_foo()- Flag on user property
- Flag on lambda passed the user object
- Use file
- Use memcache, e.g. in Google App Engine
- Use some other persistent database