google.golang.org/grpc v1.78.0

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@v1.78.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/google.golang.org/grpc@v1.78.0

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.

package sample

import (
	"context"
	"errors"
	"net"
	"testing"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/metadata"
	"google.golang.org/grpc/status"
	"google.golang.org/grpc/test/bufconn"
	emptypb "google.golang.org/protobuf/types/known/emptypb"
)

func TestGrpcClientServerUnary(t *testing.T) {
	const bufSize = 1024 * 1024
	lis := bufconn.Listen(bufSize)
	server := grpc.NewServer()

	// Register unary RPC service handler
	server.RegisterService(&grpc.ServiceDesc{
		ServiceName: "test.EchoService",
		HandlerType: (*any)(nil),
		Methods: []grpc.MethodDesc{
			{
				MethodName: "Echo",
				Handler: func(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
					in := new(emptypb.Empty)
					if err := dec(in); err != nil {
						return nil, err
					}
					if err := grpc.SendHeader(ctx, metadata.Pairs("x-resp-header", "header-value")); err != nil {
						return nil, err
					}
					if err := grpc.SetTrailer(ctx, metadata.Pairs("x-resp-trailer", "trailer-value")); err != nil {
						return nil, err
					}
					return in, nil
				},
			},
			{
				MethodName: "FailWithCode",
				Handler: func(srv any, ctx context.Context, dec func(any) error, interceptor grpc.UnaryServerInterceptor) (any, error) {
					in := new(emptypb.Empty)
					if err := dec(in); err != nil {
						return nil, err
					}
					return nil, status.Errorf(codes.PermissionDenied, "permission denied test")
				},
			},
		},
		Streams: []grpc.StreamDesc{},
	}, nil)

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

	var interceptorMethod string
	var interceptorCalled bool
	interceptor := func(ctx context.Context, method string, req, reply any, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
		interceptorCalled = true
		interceptorMethod = method
		return invoker(ctx, method, req, reply, cc, opts...)
	}

	dialer := func(context.Context, string) (net.Conn, error) {
		return lis.Dial()
	}

	cc, err := grpc.NewClient("passthrough://localhost/bufnet",
		grpc.WithContextDialer(dialer),
		grpc.WithTransportCredentials(insecure.NewCredentials()),
		grpc.WithUnaryInterceptor(interceptor),
	)
	if err != nil {
		t.Fatalf("Failed to create ClientConn: %v", err)
	}
	defer cc.Close()

	t.Run("unary RPC dispatches through interceptor and captures metadata", func(t *testing.T) {
		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
		defer cancel()

		req := &emptypb.Empty{}
		resp := &emptypb.Empty{}
		var headerMD, trailerMD metadata.MD

		err := grpc.Invoke(
			ctx,
			"/test.EchoService/Echo",
			req,
			resp,
			cc,
			grpc.Header(&headerMD),
			grpc.Trailer(&trailerMD),
		)
		if err != nil {
			t.Fatalf("grpc.Invoke failed: %v", err)
		}

		if !interceptorCalled {
			t.Fatalf("expected unary client interceptor to be invoked")
		}
		if interceptorMethod != "/test.EchoService/Echo" {
			t.Fatalf("expected interceptor method /test.EchoService/Echo, got %s", interceptorMethod)
		}
		if vals := headerMD.Get("x-resp-header"); len(vals) == 0 || vals[0] != "header-value" {
			t.Fatalf("expected response header 'header-value', got %v", headerMD)
		}
		if vals := trailerMD.Get("x-resp-trailer"); len(vals) == 0 || vals[0] != "trailer-value" {
			t.Fatalf("expected response trailer 'trailer-value', got %v", trailerMD)
		}
	})

	t.Run("unary RPC receives custom gRPC status code from server handler", func(t *testing.T) {
		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
		defer cancel()

		req := &emptypb.Empty{}
		resp := &emptypb.Empty{}
		err := grpc.Invoke(ctx, "/test.EchoService/FailWithCode", req, resp, cc)
		if err == nil {
			t.Fatalf("expected error from FailWithCode, got nil")
		}
		st, ok := status.FromError(err)
		if !ok {
			t.Fatalf("expected status error, got %v", err)
		}
		if st.Code() != codes.PermissionDenied {
			t.Fatalf("expected PermissionDenied, got %v", st.Code())
		}
	})

	t.Run("unary RPC with canceled context returns status code Canceled", func(t *testing.T) {
		ctx, cancel := context.WithCancel(context.Background())
		cancel()

		req := &emptypb.Empty{}
		resp := &emptypb.Empty{}
		err := grpc.Invoke(ctx, "/test.EchoService/Echo", req, resp, cc)
		if err == nil {
			t.Fatalf("expected error with canceled context, got nil")
		}
		st, ok := status.FromError(err)
		if !ok || st.Code() != codes.Canceled {
			t.Fatalf("expected codes.Canceled, got %v (status: %v)", err, st)
		}
	})

	t.Run("unary RPC on closed connection returns ErrClientConnClosing", func(t *testing.T) {
		closedCC, err := grpc.NewClient("passthrough://localhost/bufnet",
			grpc.WithContextDialer(dialer),
			grpc.WithTransportCredentials(insecure.NewCredentials()),
		)
		if err != nil {
			t.Fatalf("failed to create ClientConn: %v", err)
		}
		if err := closedCC.Close(); err != nil {
			t.Fatalf("failed to close ClientConn: %v", err)
		}

		req := &emptypb.Empty{}
		resp := &emptypb.Empty{}
		err = grpc.Invoke(context.Background(), "/test.EchoService/Echo", req, resp, closedCC)
		if err == nil {
			t.Fatalf("expected error on closed ClientConn, got nil")
		}
		if !errors.Is(err, grpc.ErrClientConnClosing) && status.Code(err) != codes.Canceled {
			t.Fatalf("expected ErrClientConnClosing or Canceled code, got %v", err)
		}
	})
}

{"case":{"caseId":"case:sha256:dce811a78daf1c172c79f485e8b04b42fffbac74f556da26111ff29ea150ca67","contract":["grpc.Invoke sends a unary RPC request over ClientConn, invokes configured UnaryClientInterceptor, and captures response header and trailer metadata","grpc.Invoke receives custom gRPC status code returned by the server handler","grpc.Invoke returns a status error with code Canceled when invoked with an already canceled context","grpc.Invoke returns ErrClientConnClosing when invoked on a closed ClientConn"],"goal":"verify pkg:golang/google.golang.org/grpc@v1.78.0","kind":"HOW","packages":["pkg:golang/google.golang.org/grpc@v1.78.0"],"schemaVersion":1},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","compiler":"go","compilerVersion":"1.26.6","distro":"ubuntu","ecosystem":"golang","language":"go","languageVersion":"1.26.6","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/google.golang.org/grpc@v1.78.0"],"schemaVersion":1,"subject":"pkg:golang/google.golang.org/grpc@v1.78.0","verifierAdapter":"golang@1"}

module sample

go 1.26.6

require (
	google.golang.org/grpc v1.78.0
	google.golang.org/protobuf v1.36.10
)

require (
	golang.org/x/net v0.47.0 // indirect
	golang.org/x/sys v0.38.0 // indirect
	golang.org/x/text v0.31.0 // indirect
	google.golang.org/genproto/googleapis/rpc v0.0.0-20251029180050-ab9386a59fda // indirect
)

github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
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/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/otel v1.38.0 h1:RkfdswUDRimDg0m2Az18RKOsnI8UDzppJAtj01/Ymk8=
go.opentelemetry.io/otel v1.38.0/go.mod h1:zcmtmQ1+YmQM9wrNsTGV/q/uyusom3P8RxwExxkZhjM=
go.opentelemetry.io/otel/metric v1.38.0 h1:Kl6lzIYGAh5M159u9NgiRkmoMKjvbsKtYRwgfrA6WpA=
go.opentelemetry.io/otel/metric v1.38.0/go.mod h1:kB5n/QoRM8YwmUahxvI3bO34eVtQf2i4utNVLr9gEmI=
go.opentelemetry.io/otel/sdk v1.38.0 h1:l48sr5YbNf2hpCUj/FoGhW9yDkl+Ma+LrVl8qaM5b+E=
go.opentelemetry.io/otel/sdk v1.38.0/go.mod h1:ghmNdGlVemJI3+ZB5iDEuk4bWA3GkTpW+DOoZMYBVVg=
go.opentelemetry.io/otel/sdk/metric v1.38.0 h1:aSH66iL0aZqo//xXzQLYozmWrXxyFkBJ6qT5wthqPoM=
go.opentelemetry.io/otel/sdk/metric v1.38.0/go.mod h1:dg9PBnW9XdQ1Hd6ZnRz689CbtrUp0wMMs9iPcgT9EZA=
go.opentelemetry.io/otel/trace v1.38.0 h1:Fxk5bKrDZJUH+AMyyIXGcFAPah0oRcT+LuNtJrmcNLE=
go.opentelemetry.io/otel/trace v1.38.0/go.mod h1:j1P9ivuFsTceSWe1oY+EeW3sc+Pp42sO++GHkg4wwhs=
golang.org/x/net v0.47.0 h1:Mx+4dIFzqraBXUugkia1OOvlD6LemFo1ALMHjrXDOhY=
golang.org/x/net v0.47.0/go.mod h1:/jNxtkgq5yWUGYkaZGqo27cfGZ1c5Nen03aYrrKpVRU=
golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
golang.org/x/text v0.31.0 h1:aC8ghyu4JhP8VojJ2lEHBnochRno1sgL6nEi9WGFGMM=
golang.org/x/text v0.31.0/go.mod h1:tKRAlv61yKIjGGHX/4tP1LTbc13YSec1pxVEWXzfoeM=
gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
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/grpc v1.78.0 h1:K1XZG/yGDJnzMdd/uZHAkVqJE+xIDOcmdSFZkBUicNc=
google.golang.org/grpc v1.78.0/go.mod h1:I47qjTo4OKbMkjA/aOOwxDIiPSBofUtQUI5EfpWvW7U=
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 pkg:golang/google.golang.org/grpc@v1.78.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/google.golang.org/grpc@v1.78.0"
  ]
}