// This file is @generated by prost-build.
/// %METADATA(TYPE:NAMESPACE:KEY):Z%
/// :ref:`Metadata <envoy_v3_api_msg_config.core.v3.Metadata>` info,
/// where TYPE is type of metadata (see above for supported types),
/// NAMESPACE is the filter namespace used when setting the metadata, KEY is an optional
/// lookup key in the namespace with the option of specifying nested keys separated by ':',
/// and Z is an optional parameter denoting string truncation up to Z characters long.
/// The data will be logged as a JSON string. For example, for the following ROUTE metadata:
///
/// ```text
/// ``com.test.my_filter: {"test_key": "foo", "test_object": {"inner_key": "bar"}}``
///
/// * %METADATA(ROUTE:com.test.my_filter)% will log: ``{"test_key": "foo", "test_object": {"inner_key": "bar"}}``
/// * %METADATA(ROUTE:com.test.my_filter:test_key)% will log: ``foo``
/// * %METADATA(ROUTE:com.test.my_filter:test_object)% will log: ``{"inner_key": "bar"}``
/// * %METADATA(ROUTE:com.test.my_filter:test_object:inner_key)% will log: ``bar``
/// * %METADATA(ROUTE:com.unknown_filter)% will log: ``-``
/// * %METADATA(ROUTE:com.test.my_filter:unknown_key)% will log: ``-``
/// * %METADATA(ROUTE:com.test.my_filter):25% will log (truncation at 25 characters): ``{"test_key": "foo", "test``
/// ```
///
/// .. note::
///
/// ```text
/// For typed JSON logs, this operator renders a single value with string, numeric, or boolean type
/// when the referenced key is a simple value. If the referenced key is a struct or list value, a
/// JSON struct or list is rendered. Structs and lists may be nested. In any event, the maximum
/// length is ignored.
/// ```
///
/// .. note::
///
/// ```text
/// METADATA(DYNAMIC:NAMESPACE:KEY):Z is equivalent to :ref:`DYNAMIC_METADATA(NAMESPACE:KEY):Z<config_access_log_format_dynamic_metadata>`
/// METADATA(CLUSTER:NAMESPACE:KEY):Z is equivalent to :ref:`CLUSTER_METADATA(NAMESPACE:KEY):Z<config_access_log_format_cluster_metadata>`
/// METADATA(UPSTREAM_HOST:NAMESPACE:KEY):Z is equivalent to :ref:`UPSTREAM_METADATA(NAMESPACE:KEY):Z<config_access_log_format_upstream_host_metadata>`
/// ```
///
/// .. warning::
/// This extension is treated as built-in extension and will be enabled by default now.
/// It is unnecessary to configure this extension.
#[derive(Clone, Copy, PartialEq, ::prost::Message)]
pub struct Metadata {}
