feat: add Lua filter to afterExtProcFilterPrefixes - #2054
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nacx merged 3 commits intoApr 16, 2026
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Allow Lua filters configured via EnvoyExtensionPolicy to run after the AI Gateway ext_proc filter, consistent with how Wasm filters are already handled. This enables users to leverage AIGW metadata (e.g. x-ai-eg-model header) in Lua scripts without resorting to EnvoyPatchPolicy workarounds. Fixes envoyproxy#1469 Signed-off-by: Varun Nuthalapati <nuthalapativarun@gmail.com>
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #2054 +/- ##
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Coverage 84.38% 84.38%
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Files 130 130
Lines 18116 18116
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Hits 15287 15287
Misses 1883 1883
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Description
Allow Lua filters configured via
EnvoyExtensionPolicyto run after the AI Gateway ext_proc filter, consistent with how Wasm filters are already handled.The
afterExtProcFilterPrefixesslice controls which filters AIGW's ext_proc is inserted before. Wasm was already in this list, but Lua was missing, so Lua filters would end up running before AIGW's ext_proc rather than after it. This prevented users from using Lua scripts to act on AIGW metadata (e.g. thex-ai-eg-modelheader set by ext_proc).This PR adds
EnvoyFilterLuatoafterExtProcFilterPrefixesin the same position asEnvoyFilterWasm, and adds a corresponding test case.Note: This code was written with AI assistance (Claude Code).
Related Issues/PRs (if applicable)
Fixes #1469
Special notes for reviewers (if applicable)
The fix follows the exact same pattern used for
EnvoyFilterWasm(line 799).EnvoyFilterLuais defined in theegv1a1package (envoy.filters.http.lua) so no new dependencies are introduced.