Initialize SDK

Use the instantiate method to initialize the Python SDK and instantiate an instance of the Optimizely client class that exposes API methods like Get Enabled Features. Each client corresponds to the datafile representing the state of a project for a certain environment.

Version

SDK v3.2.0

Description

The constructor accepts a configuration object to configure Optimizely.

Some parameters are optional because the SDK provides a default implementation, but you may want to override these for your production environments. For example, you may want override these to set up an error handler and logger to catch issues, an event dispatcher to manage network calls, and a User Profile Service to ensure sticky bucketing.

Parameters

The table below lists the required and optional parameters in Python.

Parameter	Type	Description
datafile optional	string	The JSON string representing the project. Must provide either `datafile` or `sdk_key`.
sdk_key optional	string	Optional string that uniquely identifies the datafile corresponding to project and environment combination. Must provide either `datafile` or `sdk_key`.
event_dispatcher optional	EventDispatcher	An event handler to manage network calls.
logger optional	logging.Logger	A logger implementation to log issues.
error_handler optional	BaseErrorHandler	An error handler object to handle errors.
user_profile_service optional	UserProfileService	A user profile service.
skip_json_validation optional	Boolean	Specifies whether the JSON should be validated. Set to `true` to skip JSON validation on the schema, or `false` to perform validation.
config_manager optional	BaseConfigManager	Implements `optimizely.config_manager.BaseConfigManager`. Responsible for providing `get_config` method which returns an instance of `optimizely.project_config.ProjectConfig`.
notification_center optional	NotificationCenter	Instance of `optimizely.notification_center.NotificationCenter`. This option is useful when providing your own `optimizely.config_manager.BaseConfigManager` implementation, which can use the same NotificationCenter instance.
access_token optional	string	(Server-side only) Optimizely SDKs can use an access token (in combination with an sdkkey) to fetch the datafile from an authenticated endpoint. Find your datafile access token in the Optimizely app at Settings>Environments. Select your secure environment, and copy the _Datafile access token.

Returns

Instantiates an instance of the Optimzely class.

Examples

In the Python SDK, you can provide either sdkKey or datafile or both.

When initializing with just the SDK key, the SDK will poll for datafile changes in the background at regular intervals.
When initializing with just the datafile, the SDK will NOT poll for datafile changes in the background.
When initializing with both the SDK key and datafile, the SDK will use the given datafile and start polling for datafile changes in the background.

Instantiate using SDK Key (recommended)

In the Python SDK, you only need to pass the SDK key value to instantiate a client. Whenever the experiment configuration changes, the SDK handles the change for you.

Include sdkKey as a string property in the options object you pass to the createInstance method.

When you provide the sdkKey, the SDK instance downloads the datafile associated with that sdkKey. When the download completes, the SDK instance updates itself to use the downloaded datafile.

from optimizely import optimizely
from optimizely.config_manager import PollingConfigManager
 
sdk_key = '123456'
conf_manager = PollingConfigManager(
   sdk_key = sdk_key,
   update_interval=10,
)
 
optimizely_client = optimizely.Optimizely(config_manager=conf_manager)

Instantiate using datafile

You can also instantiate with a hard-coded datafile. If you don't pass in an SDK key, the Optimizely Client will not automatically sync newer versions of the datafile. Any time you retrieve an updated datafile, just re-instantiate the same client.

For simple applications, all you need to provide to instantiate a client is a datafile specifying the project configuration for a given environment. For most advanced implementations, you'll want to customize the logger or error handler for your specific requirements.

from optimizely import optimizely

# Instantiate an Optimizely client
optimizely_client = optimizely.Optimizely(datafile)

Notes

Enable JSON schema validation

Skipping JSON schema validation enhances performance during instantiation. In the Python SDK, you have control over whether to validate the JSON schema of the datafile when instantiating the client. This example shows how to skip JSON schema validation:

# Skip JSON schema validation (SDK versions 0.1.1 and above)
optimizely_client = optimizely.Optimizely(datafile,
                                          skip_json_validation=True)

Use authenticated datafiles in secure environments

You can fetch the Optimizely datafile from an authenticated endpoint using a server-side (only) Optimizely SDK. To use an authenticated datafile, download your Optimizely environment's access token from the Optimizely app at Settings>Environments. Select your secure environment, and copy the Datafile access token. The example below shows how to initialize the Optimizely client using an access token and sdk_key, enabling the client to fetch the authenticated datafile and complete initialization.

# fetch the datafile from an authenticated endpoint
access_tkn = '<YOUR_DATAFILE_ACCESS_TOKEN>'
sdk_key = '<YOUR_SDK_KEY>'
optimizely_client = optimizely.Optimizely(sdk_key = sdk_key,
                                          datafile_access_token = access_tkn )

For more information on custom use of the Optimizely datafile, see Manage config (datafile).

Source files

The language/platform source files containing the implementation for Python are at optimizely.py.