toggler 0.2.0

Feature Flags Manager

Toggler

Toggler allows to set up feature toggles (flags) on a YAML file and validate whether specific flag is ON or OFF on specific environment.

How to Use

Configure Feature Toggles

Feature toggles are configured in yaml file:

---
prod:
  feature2:
    active: true
stage:
  feature1:
    active: true
    ref: r123
    deadline: 2022-01-01
  feature2:
    active: true
  feature3:
    active: false

Structure:

• modes (e.g prod, stage), defines features defined on specific mode.
• features (e.g feature1, feature2) are feature names used to identify which feature is used or not:
  • active: whether feature is enabled or not. If feature is not defined on specific mode, it is implicitly treated as disabled. This is the only required field.
  • ref: reference to feature or ticket (for convenience).
  • deadline: if set, will check if feature flag has been for too long and logs a warning if its passed a deadline.

Define mode and config file path

You can either explicitly initialize Toggler with its optional arguments, mode and path (or stream) or you can use environment variables TOGGLER_MODE and TOGGLER_CFG.

For example:

TOGGLER_MODE=prod TOGGLER_CFG=/path/to/tog.yml my-app

Initialize Toggler and check features activity

from toggler.toggler import Toggler

tog = Toggler()  # expecting specified env variables
if tog.is_active("feature1"):
    # feature1 logic
    ...
else:
    # old logic
    ...

Using toggler in tests

You can force toggle feature to make it easier to test.

from toggler.env import toggle_feature


def test_feature1_on():
    with toggle_feature("feature1", True):  # Force enable
        # test if feature1 logic works as expected
        ...


def test_feature1_off():
    with toggle_feature("feature1", False):  # Force disable
        # test if logic without feature1 works as expected
        ...