package envoy.extensions.http.ext_proc.processing_request_modifiers.mapped_attribute_builder.v3

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Extension to build custom attributes in the :ref:`request <envoy_v3_api_msg_service.ext_proc.v3.ProcessingRequest>` based on a configurable mapping. The native implementation uses the CEL expression as the key, which is not always desirable. Using this extension, one can re-map a CEL expression that references internal filter state into a more user-friendly key that decouples the value from the underlying filter implementation. If a given CEL expression fails to eval, it will not be present in the attributes struct. If this extension is configured, then the original :ref:`ProcessingRequest <envoy_v3_api_msg_service.ext_proc.v3.ProcessingRequest>`'s ``request_attributes`` are ignored, and all attributes should be explicitly set via this extension. An example configuration may look like so: .. code-block:: yaml mapped_request_attributes: "request.path": "request.path" "source.country": "metadata.filter_metadata['com.example.location_filter']['country_code']" In the above example, the complex filter_metadata expression is evaluated via CEL, and the value is stored under the friendlier ``source.country`` key. ``The ProcessingRequest`` would look like: .. code-block:: text attributes { key: "envoy.filters.http.ext_proc" value { fields { key: "request.path" value { string_value: "/profile" } } fields { key: "source.country" value { string_value: "US" } } } } .. note:: Processing request modifiers are currently in alpha.

• map<string, string> mapped_request_attributes = 1

  A map of request attributes to set in the attributes struct. The key is the attribute name, the value is the attribute value, interpretable by CEL. This allows for the re-mapping of attributes, which is not supported by the native attribute building logic.