Cilium Feature Proposal

The Go Extension support (beta) in Envoy was added a while back, however, there is no active development and improvement for the past few releases.

Additionally, Envoy upstream has recently added support for Go extension as well dynamic module. These features were not available at the time when Cilium Envoy Go Extension was added.

Cilium Docs: https://docs.cilium.io/en/stable/security/network/proxy/envoy/#go-extensions
Envoy Go Filter: https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_filters/golang_filter
Envoy Dynamic module: https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/advanced/dynamic_modules

Is your proposed feature related to a problem?

N/A

Describe the feature you'd like

Deprecate Cilium Go Extension for Envoy feature in 1.18, and remove it in 1.19

TODO:

• Discuss in the community meeting.
  • Here is the meeting note on 07-May-2025 https://docs.google.com/document/d/1Y_4chDk4rznD6UgXPlPvn3Dc7l-ZutGajUv1eF0VDwQ/edit?tab=t.0#heading=h.sll2istzuhga
• Add deprecated logs/messages if the feature is used. We can do this in 1.18 development cycle.
  • proxy: Add deprecated warning for proxylib #39419
• Remove the related code, if there is no interest from community (only in 1.19+)

(Optional) Describe your proposed solution

N/A