Edit

Python

Getting started:

1. Install ConfigCat SDK

pip install configcat-client

2. Import the package

import configcatclient

3. Create the ConfigCat client with your API Key

configcat_client = configcatclient.create_client('#YOUR-API-KEY#')

4. Get your setting value

isMyAwesomeFeatureEnabled = configcat_client.get_value('isMyAwesomeFeatureEnabled', False)
if isMyAwesomeFeatureEnabled:
    do_the_new_thing()
else:
    do_the_old_thing()

5. Stop ConfigCat client

You can safely shut down the client instance and release all associated resources on application exit.

configcat_client.stop()

Creating the ConfigCat Client

ConfigCat Client is responsible for:

  • managing the communication between your application and ConfigCat servers.
  • caching your setting values and feature flags.
  • serving values quickly in a failsafe way.

create_client() returns a client with default options.

PropertiesDescription
api_keyREQUIRED. API Key to access your feature flags and configurations. Get it from ConfigCat Management Console.

create_client_with_auto_poll(), create_client_with_lazy_load(), create_client_with_manual_poll()
Creating the client is different for each polling mode. See below for details.

We strongly recommend using the ConfigCat Client as a Singleton object in your application.

Anatomy of get_value()

ParametersDescription
keyREQUIRED. Setting-specific key. Set in ConfigCat Management Console for each setting.
default_valueREQUIRED. This value will be returned in case of an error.
userOptional, User Object. Essential when using Targeting. Read more about Targeting.
 
value = configcat_client.get_value(
    'keyOfMySetting', # Setting Key
    False, # Default value
    User('435170f4-8a8b-4b67-a723-505ac7cdea92') # Optional User Object
);

User Object

user_object = User('435170f4-8a8b-4b67-a723-505ac7cdea92')   

user_object = User('john@example.com')
ParametersDescription
identifierREQUIRED. Unique identifier of a user in your application. Can be any value, even an email address.
emailOptional parameter for easier targeting rule definitions.
countryOptional parameter for easier targeting rule definitions.
customOptional dictionary for custom attributes of a user for advanced targeting rule definitions. e.g. User role, Subscription type.
 
user_object = User('435170f4-8a8b-4b67-a723-505ac7cdea92', 'john@example', 'United Kingdom',
                {'SubscriptionType': 'Pro', 'UserRole': 'Admin'})

CDN base url (forward proxy, dedicated subscription)

You can customize your CDN path in the SDK with base_url parameter.

configcatclient.create_client_with_auto_poll(
    "#YOUR-API-KEY#", base_url="https://myCDN.configcat.com");

The following methods support tha base_url parameter:

  • configcatclient.create_client_with_auto_poll()
  • configcatclient.create_client_with_manual_poll()
  • configcatclient.create_client_with_lazy_load()

Polling Modes

The ConfigCat SDK supports 3 different polling mechanisms to acquire the setting values from ConfigCat. After latest setting values are downloaded, they are stored in the internal cache then all requests are served from there. With the following polling modes, you can customize the SDK to best fit to your application's lifecycle.

Auto polling (default)

The ConfigCat SDK downloads the latest values and stores them automatically every 60 seconds.

Use the poll_interval_seconds option parameter to change the polling interval.

configcatclient.create_client_with_auto_poll(
    "#YOUR-API-KEY#", poll_interval_seconds=95);

Adding a callback to on_configuration_changed_callback option parameter will get you notified about changes.

def configuration_changed_callback(self):
# Configuration changed.
    pass

configcatclient.create_client_with_auto_poll("#YOUR-API-KEY#", on_configuration_changed_callback=configuration_changed_callback);

Available options:

Option ParameterDescriptionDefault
poll_interval_secondsPolling interval.60
on_configuration_changed_callbackCallback to get notified about changes.-
max_init_wait_time_secondsMaximum waiting time between the client initialization and the first config acquisition in secconds.5
config_cache_classCustom cache implementation.None

Lazy loading

When calling get_value() the ConfigCat SDK downloads the latest setting values if they are not present or expired in the cache. In this case the get_value() will return the setting value after the cache is updated.

Use cache_time_to_live_seconds option parameter to set cache lifetime.

configcatclient.create_client_with_lazy_load(
    "#YOUR-API-KEY#", cache_time_to_live_seconds=600);

Use a custom config_cache_class option parameter.

from configcatclient.interfaces import ConfigCache
class InMemoryConfigCache(ConfigCache):
    def __init__(self):
        self._value = None

    def get(self):
        return self._value

    def set(self, value):
        self._value = value

configcatclient.create_client_with_lazy_load("#YOUR-API-KEY#", config_cache_class=InMemoryConfigCache);

Available options:

Option ParameterDescriptionDefault
cache_time_to_live_secondsCache TTL.60
config_cache_classCustom cache implementation.None

Manual polling

Manual polling gives you full control over when the setting values are downloaded. ConfigCat SDK will not update them automatically. Calling force_refresh() is your application's responsibility.

configcat_client = configcatclient.create_client_with_manual_poll("#YOUR-API-KEY#");
configcat_client.force_refresh();

Available options:

Option ParameterDescriptionDefault
config_cache_classCustom cache implementation.None

get_value() returns default_value if the cache is empty. Call force_refresh() to update the cache.

configcat_client = configcatclient.create_client_with_manual_poll('#YOUR-API-KEY#');
value = configcat_client.get_value('key', 'my default value') # Returns "my default value"
configcat_client.force_refresh();
value = configcat_client.get_value('key', 'my default value') # Returns "value from server"

get_all_keys()

You can query the keys from your configuration in the SDK with the get_all_keys() method.

configcat_client = configcatclient.create_client('#YOUR-API-KEY#')
keys = configcat_client.get_all_keys()

Sample Applications

Look under the hood

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