google.golang.org/grpc v1.27.0

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 pkg:golang/google.golang.org/grpc@v1.27.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/google.golang.org/grpc@v1.27.0

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:sha256:9cb65e3bb67738d2374479640340ea64b872f958ce1b6a67e9dca82c1fda6840","contract":["grpc.NewServer registers a unary ServiceDesc and reports the method via GetServiceInfo","grpc.DialContext with bufconn.Listen and grpc.WithInsecure invokes the unary method with outgoing metadata and receives the expected response","missing required incoming metadata returns codes.InvalidArgument via status.Error and is observed with status.Code on the client"],"goal":"verify pkg:golang/google.golang.org/grpc@v1.27.0","kind":"HOW","packages":["pkg:golang/google.golang.org/grpc@v1.27.0"],"schemaVersion":1},"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/google.golang.org/grpc@v1.27.0"],"schemaVersion":1,"subject":"pkg:golang/google.golang.org/grpc@v1.27.0","verifierAdapter":"golang@1"}

module sample

go 1.21

require google.golang.org/grpc v1.27.0

require (
	github.com/golang/protobuf v1.3.2 // indirect
	golang.org/x/net v0.0.0-20190311183353-d8887717615a // indirect
	golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a // indirect
	golang.org/x/text v0.3.0 // indirect
	google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55 // indirect
)

cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b h1:VKtxabqXZkF25pY9ekfRL6a582T4P37/31XEstQ5p58=
github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
github.com/golang/protobuf v1.3.2 h1:6nsPYzhq5kReh6QImI3k5qWzO4PEbvbIW2cwSfR/6xs=
github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
github.com/google/go-cmp v0.2.0 h1:+dTQ8DZQJz0Mb/HjFlkptS1FeQ4cWSnN941F8aEG4SQ=
github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
golang.org/x/net v0.0.0-20190311183353-d8887717615a h1:oWX7TPOiFAMXLq8o0ikBYfCJVlRHBcsciT5bXOrH628=
golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a h1:1BGLXjeY4akVXGgbC9HugT3Jv3hCI0z56oJR5vAMgBU=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55 h1:gSJIx1SDwno+2ElGhA4+qG2zF97qiUzTM+rQ0klBOcE=
google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
google.golang.org/grpc v1.27.0 h1:rRYRFMVgRv6E0D70Skyfsr28tDXIuuPZyWGMPdMcnXg=
google.golang.org/grpc v1.27.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8abTk=
honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/google.golang.org/grpc@v1.27.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/google.golang.org/grpc@v1.27.0"
  ]
}

package main

import (
	"context"
	"fmt"
	"net"
	"os"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/metadata"
	"google.golang.org/grpc/status"
	"google.golang.org/grpc/test/bufconn"
)

type byteCodec struct{}

func (byteCodec) Marshal(v interface{}) ([]byte, error) {
	b, ok := v.(*[]byte)
	if !ok {
		return nil, fmt.Errorf("unexpected marshal type %T", v)
	}
	return *b, nil
}

func (byteCodec) Unmarshal(data []byte, v interface{}) error {
	b, ok := v.(*[]byte)
	if !ok {
		return fmt.Errorf("unexpected unmarshal type %T", v)
	}
	*b = append((*b)[:0], data...)
	return nil
}

func (byteCodec) String() string {
	return "bytes"
}

type echoService interface {
	Echo(ctx context.Context, in *[]byte) (*[]byte, error)
}

type echoServer struct{}

func (s *echoServer) Echo(ctx context.Context, in *[]byte) (*[]byte, error) {
	md, ok := metadata.FromIncomingContext(ctx)
	if !ok || len(md.Get("x-req-id")) == 0 || md.Get("x-req-id")[0] != "req-42" {
		return nil, status.Error(codes.InvalidArgument, "missing metadata")
	}
	out := []byte("ack:" + string(*in))
	return &out, nil
}

func echoHandler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
	in := new([]byte)
	if err := dec(in); err != nil {
		return nil, err
	}
	if interceptor == nil {
		return srv.(echoService).Echo(ctx, in)
	}
	info := &grpc.UnaryServerInfo{
		Server:     srv,
		FullMethod: "/sample.EchoService/Echo",
	}
	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
		return srv.(echoService).Echo(ctx, req.(*[]byte))
	}
	return interceptor(ctx, in, info, handler)
}

func main() {
	lis := bufconn.Listen(1024 * 1024)
	defer lis.Close()

	srv := grpc.NewServer(grpc.CustomCodec(byteCodec{}))
	srv.RegisterService(&grpc.ServiceDesc{
		ServiceName: "sample.EchoService",
		HandlerType: (*echoService)(nil),
		Methods: []grpc.MethodDesc{
			{
				MethodName: "Echo",
				Handler:    echoHandler,
			},
		},
		Streams:  []grpc.StreamDesc{},
		Metadata: "sample.proto",
	}, &echoServer{})

	info := srv.GetServiceInfo()
	svcInfo, ok := info["sample.EchoService"]
	if !ok || len(svcInfo.Methods) != 1 || svcInfo.Methods[0].Name != "Echo" {
		fmt.Fprintln(os.Stderr, "service registration check failed")
		os.Exit(1)
	}

	go func() {
		_ = srv.Serve(lis)
	}()
	defer srv.Stop()

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	conn, err := grpc.DialContext(
		ctx,
		"bufnet",
		grpc.WithContextDialer(func(ctx context.Context, _ string) (net.Conn, error) {
			return lis.Dial()
		}),
		grpc.WithInsecure(),
		grpc.WithDefaultCallOptions(grpc.CallCustomCodec(byteCodec{})),
	)
	if err != nil {
		fmt.Fprintf(os.Stderr, "dial failed: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close()

	outCtx := metadata.AppendToOutgoingContext(ctx, "x-req-id", "req-42")
	req := []byte("ping")
	var resp []byte
	if err := conn.Invoke(outCtx, "/sample.EchoService/Echo", &req, &resp); err != nil {
		fmt.Fprintf(os.Stderr, "invoke failed: %v\n", err)
		os.Exit(1)
	}
	if string(resp) != "ack:ping" {
		fmt.Fprintf(os.Stderr, "unexpected response: %q\n", string(resp))
		os.Exit(1)
	}

	var badResp []byte
	err = conn.Invoke(ctx, "/sample.EchoService/Echo", &req, &badResp)
	if status.Code(err) != codes.InvalidArgument {
		fmt.Fprintf(os.Stderr, "expected InvalidArgument, got %v\n", err)
		os.Exit(1)
	}

	fmt.Println("contract ok")
}