http: adds support for formatter extensions in mutation
Commit Message: http: adds support for metadata formatter in mutation
Additional Description:
Previously, %METADATA% format is not supported in header additions. This adds the formatters field in the router configuration, and enables users to use the formatter extensions in header mutation values, notably envoy.formatter.metadata extension.
Fixes https://github.com/envoyproxy/envoy/issues/34671
Risk Level: low Testing: unit tests Docs Changes: done Release Notes: done Platform Specific Features: N/A [Optional Runtime guard:] [Optional Fixes #Issue] [Optional Fixes commit #PR or SHA] [Optional Deprecated:] [Optional API Considerations:]
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CC @envoyproxy/api-shepherds: Your approval is needed for changes made to (api/envoy/|docs/root/api-docs/).
envoyproxy/api-shepherds assignee is @mattklein123
CC @envoyproxy/api-watchers: FYI only for changes made to (api/envoy/|docs/root/api-docs/).
i won't be able to have cycles to land this - closing 🙏