add instructions for darwin/arm64

README.md

@@ -2,10 +2,38 @@
 
 For some platforms, envoy is only distributed via docker images.
 
-This repo contains: 
- - a utility to extract envoy binaries from upstream container images
- - releases to house the envoy binary assets in an easily accessible place
+This repo contains:
+
+- a utility to extract envoy binaries from upstream container images
+- releases to house the envoy binary assets in an easily accessible place
 
 # Releasing
 
 When a release tag is created, the envoy binaries will be automatically extracted from the matching `envoyproxy/envoy` image tag and uploaded to the release.
+
+# Building Envoy for darwin/arm64
+
+Currently there's no way to run a github action on darwin/arm64, so the build must be done manually:
+
+1. Clone envoyproxy/envoy
+ ```bash
+ git clone [email protected]:envoyproxy/envoy
+ ```
+1. Checkout the release tag
+ ```bash
+ git checkout v1.23.0
+ ```
+1. Build
+ ```bash
+ bazelisk build -c "opt" //source/exe:envoy-static --config=sizeopt
+ ```
+1. Wait a **very** long time.
+1. Copy binary
+ ```bash
+ cp -f bazel-bin/source/exe/envoy-static ~/Downloads/envoy-darwin-arm64
+ ```
+1. Produce shasum
+ ```bash
+ shasum -a 256 ~/Downloads/envoy-darwin-arm64 > ~/Downloads/envoy-darwin-arm64.sha256
+ ```
+1. Drag & Drop the files to the release