egctl: add new formula

egctl is a command line tool to provide additional functionality
for Envoy Gateway users, add a formula make it easier for brew
users to install it.

.github/autobump.txt

@@ -684,6 +684,7 @@ editorconfig-checker
 efl
 efm-langserver
 eg-examples
+egctl
 eget
 ehco
 eigenpy

Formula/e/egctl.rb

@@ -0,0 +1,119 @@
+class Egctl < Formula
+  desc "Command-line utility for operating Envoy Gateway"
+  homepage "https://gateway.envoyproxy.io/"
+  url "https://github.com/envoyproxy/gateway/archive/refs/tags/v1.0.2.tar.gz"
+  sha256 "05406182dc165513925cf60722582613d4de9ea789d60e014e6da456bb229f65"
+  license "Apache-2.0"
+  head "https://github.com/envoyproxy/gateway.git", branch: "main"
+
+  depends_on "go" => :build
+
+  def install
+    ldflags = %W[
+      -s -w
+      -X github.com/envoyproxy/gateway/internal/cmd/version.envoyGatewayVersion=#{version}
+      -X github.com/envoyproxy/gateway/internal/cmd/version.gitCommitID=#{tap.user}
+    ]
+    system "go", "build", *std_go_args(ldflags:), "./cmd/egctl"
+
+    generate_completions_from_executable(bin/"egctl", "completion")
+  end
+
+  test do
+    assert_equal version.to_s, shell_output("#{bin}/egctl version --remote=false").strip
+
+    (testpath/"input.yaml").write <<~EOS
+      apiVersion: gateway.networking.k8s.io/v1
+      kind: GatewayClass
+      metadata:
+        name: eg
+      spec:
+        controllerName: gateway.envoyproxy.io/gatewayclass-controller
+      ---
+      apiVersion: gateway.networking.k8s.io/v1
+      kind: Gateway
+      metadata:
+        name: eg
+        namespace: default
+      spec:
+        gatewayClassName: eg
+        listeners:
+          - name: http
+            protocol: HTTP
+            port: 80
+      ---
+      apiVersion: v1
+      kind: Namespace
+      metadata:
+        name: default 
+      ---
+      apiVersion: v1
+      kind: Service
+      metadata:
+        name: backend
+        namespace: default
+        labels:
+          app: backend
+          service: backend
+      spec:
+        clusterIP: "1.1.1.1"
+        type: ClusterIP
+        ports:
+          - name: http
+            port: 3000
+            targetPort: 3000
+            protocol: TCP
+        selector:
+          app: backend
+      ---
+      apiVersion: gateway.networking.k8s.io/v1
+      kind: HTTPRoute
+      metadata:
+        name: backend
+        namespace: default
+      spec:
+        parentRefs:
+          - name: eg
+        hostnames:
+          - "www.example.com"
+        rules:
+          - backendRefs:
+              - group: ""
+                kind: Service
+                name: backend
+                port: 3000
+                weight: 1
+            matches:
+              - path:
+                  type: PathPrefix
+                  value: /
+    EOS
+
+    expected = <<~EOS
+      xds:
+        default/eg:
+          '@type': type.googleapis.com/envoy.admin.v3.RoutesConfigDump
+          dynamicRouteConfigs:
+          - routeConfig:
+              '@type': type.googleapis.com/envoy.config.route.v3.RouteConfiguration
+              ignorePortInHostMatching: true
+              name: default/eg/http
+              virtualHosts:
+              - domains:
+                - www.example.com
+                name: default/eg/http/www_example_com
+                routes:
+                - match:
+                    prefix: /
+                  name: httproute/default/backend/rule/0/match/0/www_example_com
+                  route:
+                    cluster: httproute/default/backend/rule/0
+                    upgradeConfigs:
+                    - upgradeType: websocket
+
+      EOS
+
+    output = shell_output("#{bin}/egctl x translate --from gateway-api --to xds -t route -f #{testpath}/input.yaml")
+    assert_equal output, expected
+  end
+end