chore: cross-compile docker images with buildx (#3503)

ci/release-image/build.sh

@@ -1,11 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-main() {
-  cd "$(dirname "$0")/../.."
-  source ./ci/lib.sh
-
-  docker build -t "codercom/code-server-$ARCH:$VERSION" -f ./ci/release-image/Dockerfile .
-}
-
-main "$@"

ci/release-image/docker-bake.hcl

@@ -0,0 +1,25 @@
+# Use this file from the top of the repo, with `-f ci/release-image/docker-bake.hcl`
+
+# Uses env var VERSION if set;
+# normally, this is set by ci/lib.sh
+variable "VERSION" {
+    default = "latest"
+}
+
+group "default" {
+    targets = ["code-server-amd64", "code-server-arm64"]
+}
+
+target "code-server-amd64" {
+    dockerfile = "ci/release-image/Dockerfile"
+    tags = ["docker.io/codercom/code-server-amd64:${VERSION}"]
+    platforms = ["linux/amd64"]
+    output = ["type=tar,dest=./release-images/code-server-amd64-${VERSION}.tar"]
+}
+
+target "code-server-arm64" {
+    dockerfile = "ci/release-image/Dockerfile"
+    tags = ["docker.io/codercom/code-server-arm64:${VERSION}"]
+    platforms = ["linux/arm64"]
+    output = ["type=tar,dest=./release-images/code-server-arm64-${VERSION}.tar"]
+}