2.0.0

[2.0.0] - 2023-02-22

The latest version of this SDK supports LaunchDarkly's new custom contexts feature. Contexts are an evolution of a previously-existing concept, "users." Contexts let you create targeting rules for feature flags based on a variety of different information, including attributes pertaining to users, organizations, devices, and more. You can even combine contexts to create "multi-contexts."

This feature is only available to members of LaunchDarkly's Early Access Program (EAP). If you're in the EAP, you can use contexts by updating your SDK to the latest version and, if applicable, updating your Relay Proxy. Outdated SDK versions do not support contexts, and will cause unpredictable flag evaluation behavior.

If you are not in the EAP, only use single contexts of kind "user", or continue to use the user type if available. If you try to create contexts, the context will be sent to LaunchDarkly, but any data not related to the user object will be ignored.

For detailed information about this version, please refer to the list below. For information on how to upgrade from the previous version, please read the migration guide.

Added:

• Added a new module, ldclient_context, which defines the new "context" model.
• All SDK methods that took an ldclient_user:user() now accept an ldclient_context:context() as well.
• Added ldclient_flagbuilder:if_match/4, ldclient_flagbuilder:if_not_match/4, ldclient_flagbuilder:and_match/4, and ldclient_flagbuilder:and_not_match/4 which allow creating rules targeting specific context kinds using ldclient_testdata.

Changed (breaking changes from 1.x):

• The secondary meta-attribute, which previously affected percentage rollouts, no longer exists. If you set an attribute with that name in ldclient_context:context(), it will simply be a custom attribute like any other.
• Evaluations now treat the anonymous attribute as a simple boolean, with no distinction between a false state and an undefined state.
• The binary() values in private_attributes in the configuration map now represent attribute references. If an attribute name had started with a /, then that will need to be escaped. For instance /myAttribute would now reference an attribute named myAttribute not an attribute named /myAttribute. The attribute reference would need to be updated to the escaped form /~1myAttribute.
• ldclient_flagbuilder:variation_for_all_users has been replaced with ldclient_flagbuilder:variation_for_all and now applies to contexts.
• ldclient_flagbuilder:variation_for_user has been replaced with ldclient_flagbuilder:variation_for_context and requires a context kind to be provided.
• user_keys_capacity has been replaced with context_keys_capacity in the option configuration map.

Changed (behavioral changes):

• The SDK can now evaluate segments that have rules referencing other segments.
• Analytics event data now uses a new JSON schema due to differences between the context model and the old user model.

Removed:

• Removed the secondary meta-attribute in ldclient_user:user().
• The ldclient:alias method no longer exists because alias events are not needed in the new context model.
• The inline_users_in_events option no longer exists because it is not relevant in the new context model.