github.com/envoyproxy/go-control-plane/envoy v1.37.0: v3.Cluster_Type

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_Type in pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.37.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.37.0
Demonstrate these symbols/APIs:
  - github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster_Type

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:a6e2f5a86f273f9a32bd1a90d63f7dd9aca2b4c7349b9a8cc36785c3c862e7e4","contract":["Cluster_Type satisfies isCluster_ClusterDiscoveryType and assigns standard discovery types to Envoy Cluster messages","Cluster.GetType returns the discovery enum wrapped by Cluster_Type or defaults to Cluster_STATIC when unset","Protobuf serialization round-trip of Cluster preserves the Cluster_Type wrapper and its discovery enum value"],"goal":"verify github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster_Type in pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.37.0","kind":"HOW","packages":["pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.37.0"],"schemaVersion":1,"symbols":["github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster_Type"]},"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@v1.37.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.37.0","symbols":["github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster_Type"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require (
	github.com/envoyproxy/go-control-plane/envoy v1.37.0
	google.golang.org/protobuf v1.36.11
)

require (
	cel.dev/expr v0.24.0 // indirect
	github.com/cncf/xds/go v0.0.0-20251110193048-8bfbf64dc13e // indirect
	github.com/envoyproxy/protoc-gen-validate v1.3.0 // indirect
	github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 // indirect
	google.golang.org/genproto/googleapis/api v0.0.0-20251029180050-ab9386a59fda // indirect
	google.golang.org/genproto/googleapis/rpc v0.0.0-20251029180050-ab9386a59fda // indirect
)

cel.dev/expr v0.24.0 h1:56OvJKSH3hDGL0ml5uSxZmz3/3Pq4tJ+fb1unVLAFcY=
cel.dev/expr v0.24.0/go.mod h1:hLPLo1W4QUmuYdA72RBX06QTs6MXw941piREPl3Yfiw=
github.com/cncf/xds/go v0.0.0-20251110193048-8bfbf64dc13e h1:gt7U1Igw0xbJdyaCM5H2CnlAlPSkzrhsebQB6WQWjLA=
github.com/cncf/xds/go v0.0.0-20251110193048-8bfbf64dc13e/go.mod h1:KdCmV+x/BuvyMxRnYBlmVaq4OLiKW6iRQfvC62cvdkI=
github.com/envoyproxy/go-control-plane/envoy v1.37.0 h1:u3riX6BoYRfF4Dr7dwSOroNfdSbEPe9Yyl09/B6wBrQ=
github.com/envoyproxy/go-control-plane/envoy v1.37.0/go.mod h1:DReE9MMrmecPy+YvQOAOHNYMALuowAnbjjEMkkWOi6A=
github.com/envoyproxy/protoc-gen-validate v1.3.0 h1:TvGH1wof4H33rezVKWSpqKz5NXWg5VPuZ0uONDT6eb4=
github.com/envoyproxy/protoc-gen-validate v1.3.0/go.mod h1:HvYl7zwPa5mffgyeTUHA9zHIH36nmrm7oCbo4YKoSWA=
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/genproto/googleapis/api v0.0.0-20251029180050-ab9386a59fda h1:+2XxjfsAu6vqFxwGBRcHiMaDCuZiqXGDUDVWVtrFAnE=
google.golang.org/genproto/googleapis/api v0.0.0-20251029180050-ab9386a59fda/go.mod h1:fDMmzKV90WSg1NbozdqrE64fkuTv6mlq2zxo9ad+3yo=
google.golang.org/genproto/googleapis/rpc v0.0.0-20251029180050-ab9386a59fda h1:i/Q+bfisr7gq6feoJnS/DlpdwEL4ihp41fvRiM3Ork0=
google.golang.org/genproto/googleapis/rpc v0.0.0-20251029180050-ab9386a59fda/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

{
  "schemaVersion": 1,
  "goal": "verify github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster_Type in pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.37.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/envoyproxy/go-control-plane/envoy@v1.37.0"
  ],
  "symbols": [
    "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3.Cluster_Type"
  ]
}

package main

import (
	"fmt"
	"os"

	clusterv3 "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
	"google.golang.org/protobuf/proto"
)

func main() {
	// 1. Cluster_Type satisfies isCluster_ClusterDiscoveryType and assigns standard discovery types to Envoy Cluster messages
	{
		ct := &clusterv3.Cluster_Type{Type: clusterv3.Cluster_LOGICAL_DNS}
		cluster := &clusterv3.Cluster{
			Name:                 "test-cluster",
			ClusterDiscoveryType: ct,
		}

		discType, ok := cluster.GetClusterDiscoveryType().(*clusterv3.Cluster_Type)
		if !ok || discType.Type != clusterv3.Cluster_LOGICAL_DNS {
			fmt.Fprintf(os.Stderr, "failed type assertion to Cluster_Type: ok=%v\n", ok)
			os.Exit(1)
		}

		types := []clusterv3.Cluster_DiscoveryType{
			clusterv3.Cluster_STATIC,
			clusterv3.Cluster_STRICT_DNS,
			clusterv3.Cluster_LOGICAL_DNS,
			clusterv3.Cluster_EDS,
			clusterv3.Cluster_ORIGINAL_DST,
		}

		for _, t := range types {
			c := &clusterv3.Cluster{
				Name:                 "enum-cluster",
				ClusterDiscoveryType: &clusterv3.Cluster_Type{Type: t},
			}
			disc, ok := c.GetClusterDiscoveryType().(*clusterv3.Cluster_Type)
			if !ok || disc.Type != t {
				fmt.Fprintf(os.Stderr, "mismatch for type %v\n", t)
				os.Exit(1)
			}
		}
	}

	// 2. Cluster.GetType returns the discovery enum wrapped by Cluster_Type or defaults to Cluster_STATIC when unset
	{
		clusterWithCustomType := &clusterv3.Cluster{
			Name:                 "configured-cluster",
			ClusterDiscoveryType: &clusterv3.Cluster_Type{Type: clusterv3.Cluster_STRICT_DNS},
		}
		if clusterWithCustomType.GetType() != clusterv3.Cluster_STRICT_DNS {
			fmt.Fprintf(os.Stderr, "expected STRICT_DNS, got %v\n", clusterWithCustomType.GetType())
			os.Exit(1)
		}

		emptyCluster := &clusterv3.Cluster{Name: "default-cluster"}
		if emptyCluster.GetClusterDiscoveryType() != nil {
			fmt.Fprintf(os.Stderr, "expected nil ClusterDiscoveryType\n")
			os.Exit(1)
		}
		if emptyCluster.GetType() != clusterv3.Cluster_STATIC {
			fmt.Fprintf(os.Stderr, "expected Cluster_STATIC default, got %v\n", emptyCluster.GetType())
			os.Exit(1)
		}
	}

	// 3. Protobuf serialization round-trip of Cluster preserves the Cluster_Type wrapper and its discovery enum value
	{
		original := &clusterv3.Cluster{
			Name:                 "roundtrip-cluster",
			ClusterDiscoveryType: &clusterv3.Cluster_Type{Type: clusterv3.Cluster_EDS},
		}

		data, err := proto.Marshal(original)
		if err != nil {
			fmt.Fprintf(os.Stderr, "proto.Marshal failed: %v\n", err)
			os.Exit(1)
		}

		decoded := &clusterv3.Cluster{}
		if err := proto.Unmarshal(data, decoded); err != nil {
			fmt.Fprintf(os.Stderr, "proto.Unmarshal failed: %v\n", err)
			os.Exit(1)
		}

		discType, ok := decoded.GetClusterDiscoveryType().(*clusterv3.Cluster_Type)
		if !ok {
			fmt.Fprintf(os.Stderr, "decoded ClusterDiscoveryType is not *Cluster_Type\n")
			os.Exit(1)
		}
		if discType.Type != clusterv3.Cluster_EDS {
			fmt.Fprintf(os.Stderr, "expected EDS after unmarshal, got %v\n", discType.Type)
			os.Exit(1)
		}
		if decoded.GetType() != clusterv3.Cluster_EDS {
			fmt.Fprintf(os.Stderr, "decoded GetType() expected EDS, got %v\n", decoded.GetType())
			os.Exit(1)
		}
	}

	fmt.Println("PASS: Envoy Cluster_Type contract verification passed")
}