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Python client for the Unleash feature toggle system!

Project description


Coverage Status PyPI version PyPI - Python Version License: MIT

This is the Python client for Unleash. It implements Client Specifications 1.0 and checks compliance based on spec in unleash/client-specifications

What it supports:

  • Default activation strategies using 32-bit Murmerhash3
  • Custom strategies
  • Full client lifecycle:
    • Client registers with Unleash server
    • Client periodically fetches feature toggles and stores to on-disk cache
    • Client periodically sends metrics to Unleash Server
  • Tested on Linux (Ubuntu), OSX, and Windows

Check out the project documentation and the changelog.


Check out the package on Pypi!

pip install UnleashClient



from UnleashClient import UnleashClient
client = UnleashClient("", "My Program")

To clean up gracefully:



Argument Description Required? Type Default Value
url Unleash server URL Y String N/A
app_name Name of your program Y String N/A
environment Name of current environment N String default
instance_id Unique ID for your program N String unleash-client-python
refresh_interval How often the unleash client should check for configuration changes. N Integer 15
metrics_interval How often the unleash client should send metrics to server. N Integer 60
disable_metrics Disables sending metrics to Unleash server. N Boolean F
disable_registration Disables registration with Unleash server. N Boolean F
custom_headers Custom headers to send to Unleash. N Dictionary {}
custom_strategies Custom strategies you'd like UnleashClient to support. N Dictionary {}

Checking if a feature is enabled

A check of a simple toggle:

client.is_enabled("My Toggle")

Specifying a default value:

client.is_enabled("My Toggle", default_value=True)

Supplying application context:

app_context = {"userId": ""}
client.is_enabled("User ID Toggle", app_context)

Supplying a fallback function:

def custom_fallback(feature_name: str, context: dict) -> bool:
    return True

client.is_enabled("My Toggle", fallback_function=custom_fallback)
  • Must accept the fature name and context as an argument.
  • Client will evaluate the fallback function only if exception occurs when calling the is_enabled() method i.e. feature flag not found or other general exception.
  • If both a default_value and fallback_function are supplied, client will define the default value by ORing the default value and the output of the fallback function.

Getting a variant

Checking for a variant:

context = {'userId': '2'}  # Context must have userId, sessionId, or remoteAddr.  If none are present, distribution will be random.

variant = client.get_variant("MyvariantToggle", context)

> {
>    "name": "variant1",
>    "payload": {
>        "type": "string",
>        "value": "val1"
>        },
>    "enabled": True
> }

For more information about variants, see the Beta feature documentation.

Project details

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Files for UnleashClient, version 3.4.2
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