OpenFeature provider backed by PostHog feature flags.

Requires the optional :open_feature dependency:

{:open_feature, "~> 0.1"}

Usage

{:ok, _provider} = OpenFeature.set_provider(%PostHog.OpenFeature.Provider{})
client = OpenFeature.get_client()

OpenFeature.Client.get_boolean_value(client, "new-dashboard", false,
  context: %{
    "targeting_key" => "user-123",
    "plan" => "enterprise",
    "groups" => %{"company" => "acme"},
    "group_properties" => %{"company" => %{"size" => 250}}
  }
)

Options

• :supervisor_name - PostHog instance to evaluate flags with. Defaults to PostHog.
• :default_distinct_id - distinct ID used when the evaluation context has no targeting_key. When unset, such evaluations fail with :targeting_key_missing.
• :send_feature_flag_events - whether evaluations fire $feature_flag_called events. Defaults to true.

Evaluation context

Keys can be strings or atoms.

• targeting_key - used as the PostHog distinct_id.
• groups - map of group type to group key.
• group_properties - map of group type to group properties.
• Every other key is sent as a person property.

Resolution

• Boolean flags resolve to whether the flag is enabled.
• String flags resolve to the variant key.
• Number flags resolve to the variant key parsed as a number, including unsigned hexadecimal integers such as 0x10.
• Map flags resolve to the flag's JSON object or array payload. The upstream OpenFeature SDK requires a map default (%{}), even for array payloads; get_map_value/4 can return a list when the payload is an array.

For string, number, and map reads, a disabled flag returns the default value, unless it still carries a variant (or object/array payload, for maps). That value is then returned, as in the Node and Python providers. Boolean reads return the flag's enabled state, including false regardless of the default. Reading an enabled flag whose value doesn't fit the requested type returns the default value with error_code: :type_mismatch. Unknown flags return :flag_not_found.

Resolution details include flag_metadata["posthog_reason"] when PostHog supplies an evaluation reason. Off results use :disabled when the server explicitly reports the flag_disabled reason code, otherwise :default.

The OpenFeature Elixir SDK has no error tuple for :type_mismatch or :targeting_key_missing, so these are returned as resolution details with reason: :error and run after hooks rather than error hooks.