github.com/envoyproxy/go-control-plane/envoy v1.36.0: v3.Cluster

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster in pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0
Demonstrate these symbols/APIs:
  - github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:491bc02f0f3027ad4f0df2bbf7c02e7f608656613fbc372f5cef47090bea0d92","contract":["envoy Cluster v3 message initializes with valid discovery type, connect timeout, and endpoint socket address"],"goal":"verify github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster in pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0","kind":"HOW","packages":["pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0"],"schemaVersion":1,"symbols":["github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0","symbols":["github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster"],"verifierAdapter":"golang@1"}

module sample

go 1.23.0

require github.com/envoyproxy/go-control-plane/envoy v1.36.0

require (
	github.com/cncf/xds/go v0.0.0-20250501225837-2ac532fd4443 // indirect
	github.com/envoyproxy/protoc-gen-validate v1.2.1 // indirect
	github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 // indirect
	google.golang.org/protobuf v1.36.10 // indirect
)

github.com/cncf/xds/go v0.0.0-20250501225837-2ac532fd4443 h1:aQ3y1lwWyqYPiWZThqv1aFbZMiM9vblcSArJRf2Irls=
github.com/cncf/xds/go v0.0.0-20250501225837-2ac532fd4443/go.mod h1:W+zGtBO5Y1IgJhy4+A9GOqVhqLpfZi+vwmdNXUehLA8=
github.com/envoyproxy/go-control-plane/envoy v1.36.0 h1:yg/JjO5E7ubRyKX3m07GF3reDNEnfOboJ0QySbH736g=
github.com/envoyproxy/go-control-plane/envoy v1.36.0/go.mod h1:ty89S1YCCVruQAm9OtKeEkQLTb+Lkz0k8v9W0Oxsv98=
github.com/envoyproxy/protoc-gen-validate v1.2.1 h1:DEo3O99U8j4hBFwbJfrz9VtgcDfUKS7KJ7spH3d86P8=
github.com/envoyproxy/protoc-gen-validate v1.2.1/go.mod h1:d/C80l/jxXLdfEIhX1W2TmLfsJ31lvEjwamM4DxlWXU=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 h1:GFCKgmp0tecUJ0sJuv4pzYCqS9+RGSn52M3FUwPs+uo=
github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10/go.mod h1:t/avpk3KcrXxUnYOhZhMXJlSEyie6gQbtLq5NM3loB8=
google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

{
  "schemaVersion": 1,
  "goal": "verify github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster in pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.36.0"
  ],
  "symbols": [
    "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster"
  ]
}

package main

import (
	"fmt"
	"time"

	clusterv3 "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
	corev3 "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
	endpointv3 "github.com/envoyproxy/go-control-plane/envoy/config/endpoint/v3"
	"google.golang.org/protobuf/types/known/durationpb"
)

func main() {
	cluster := &clusterv3.Cluster{
		Name:                 "service_backend",
		ConnectTimeout:       durationpb.New(5 * time.Second),
		ClusterDiscoveryType: &clusterv3.Cluster_Type{Type: clusterv3.Cluster_LOGICAL_DNS},
		DnsLookupFamily:      clusterv3.Cluster_V4_ONLY,
		LbPolicy:             clusterv3.Cluster_ROUND_ROBIN,
		LoadAssignment: &endpointv3.ClusterLoadAssignment{
			ClusterName: "service_backend",
			Endpoints: []*endpointv3.LocalityLbEndpoints{
				{
					LbEndpoints: []*endpointv3.LbEndpoint{
						{
							HostIdentifier: &endpointv3.LbEndpoint_Endpoint{
								Endpoint: &endpointv3.Endpoint{
									Address: &corev3.Address{
										Address: &corev3.Address_SocketAddress{
											SocketAddress: &corev3.SocketAddress{
												Protocol: corev3.SocketAddress_TCP,
												Address:  "127.0.0.1",
												PortSpecifier: &corev3.SocketAddress_PortValue{
													PortValue: 8080,
												},
											},
										},
									},
								},
							},
						},
					},
				},
			},
		},
	}

	if cluster.GetName() != "service_backend" {
		panic("expected cluster name service_backend")
	}
	if cluster.GetConnectTimeout().GetSeconds() != 5 {
		panic("expected connect timeout 5 seconds")
	}
	if cluster.GetLbPolicy() != clusterv3.Cluster_ROUND_ROBIN {
		panic("expected round robin lb policy")
	}

	endpoints := cluster.GetLoadAssignment().GetEndpoints()
	if len(endpoints) != 1 {
		panic("expected 1 locality lb endpoint")
	}
	lbEndpoints := endpoints[0].GetLbEndpoints()
	if len(lbEndpoints) != 1 {
		panic("expected 1 lb endpoint")
	}
	sockAddr := lbEndpoints[0].GetEndpoint().GetAddress().GetSocketAddress()
	if sockAddr.GetAddress() != "127.0.0.1" || sockAddr.GetPortValue() != 8080 {
		panic("expected socket address 127.0.0.1:8080")
	}

	fmt.Println("PASS: Envoy Cluster v3 verification successful")
}