google.golang.org/grpc v1.27.0: DialContext

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 google.golang.org/grpc.DialContext in 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
Demonstrate these symbols/APIs:
  - google.golang.org/grpc.DialContext

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:sha256:58b9c3793f97c2cc65a344fde554ddf3d9123c292eb7018d2f7d382bdd40e27b","contract":["grpc.DialContext creates a non-blocking ClientConn to an in-memory listener and transitions to Shutdown on Close","grpc.DialContext with grpc.WithBlock establishes a Ready connection before returning","grpc.DialContext with grpc.WithBlock returns context.Canceled when context is already canceled"],"goal":"verify google.golang.org/grpc.DialContext in pkg:golang/google.golang.org/grpc@v1.27.0","kind":"HOW","packages":["pkg:golang/google.golang.org/grpc@v1.27.0"],"schemaVersion":1,"symbols":["google.golang.org/grpc.DialContext"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","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","symbols":["google.golang.org/grpc.DialContext"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

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=

package sample

import (
	"context"
	"net"

	"google.golang.org/grpc"
	"google.golang.org/grpc/test/bufconn"
)

// ServerWrapper manages an in-memory gRPC server and bufconn listener.
type ServerWrapper struct {
	Server   *grpc.Server
	Listener *bufconn.Listener
}

// NewServerWrapper creates and returns a ServerWrapper with a bufconn listener.
func NewServerWrapper(bufSize int, opt ...grpc.ServerOption) *ServerWrapper {
	lis := bufconn.Listen(bufSize)
	s := grpc.NewServer(opt...)
	return &ServerWrapper{
		Server:   s,
		Listener: lis,
	}
}

// Start launches the gRPC server in a separate goroutine.
func (sw *ServerWrapper) Start() {
	go func() {
		_ = sw.Server.Serve(sw.Listener)
	}()
}

// Stop stops the server and closes the in-memory listener.
func (sw *ServerWrapper) Stop() {
	sw.Server.Stop()
	_ = sw.Listener.Close()
}

// DialBufnet creates a ClientConn connected to the provided bufconn listener using grpc.DialContext.
func DialBufnet(ctx context.Context, lis *bufconn.Listener, opts ...grpc.DialOption) (*grpc.ClientConn, error) {
	dialer := func(ctx context.Context, addr string) (net.Conn, error) {
		return lis.Dial()
	}
	baseOpts := []grpc.DialOption{
		grpc.WithContextDialer(dialer),
		grpc.WithInsecure(),
	}
	return grpc.DialContext(ctx, "bufnet", append(baseOpts, opts...)...)
}

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

package main

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

	"google.golang.org/grpc"
	"google.golang.org/grpc/connectivity"
	"sample"
)

func main() {
	if err := runContract(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All gRPC DialContext contract tests passed.")
}

func runContract() error {
	ctx := context.Background()

	wrapper := sample.NewServerWrapper(1024 * 1024)
	if wrapper.Server == nil || wrapper.Listener == nil {
		return fmt.Errorf("expected non-nil Server and Listener")
	}
	wrapper.Start()
	defer wrapper.Stop()

	// 1. grpc.DialContext creates a non-blocking ClientConn to an in-memory listener
	cc, err := sample.DialBufnet(ctx, wrapper.Listener)
	if err != nil {
		return fmt.Errorf("failed to dial bufnet: %w", err)
	}
	if cc.Target() != "bufnet" {
		_ = cc.Close()
		return fmt.Errorf("expected target 'bufnet', got %q", cc.Target())
	}
	if err := cc.Close(); err != nil {
		return fmt.Errorf("failed to close ClientConn: %w", err)
	}
	if cc.GetState() != connectivity.Shutdown {
		return fmt.Errorf("expected state Shutdown after Close, got %v", cc.GetState())
	}

	// 2. grpc.DialContext with grpc.WithBlock establishes a Ready connection before returning
	blockCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	blockCC, err := sample.DialBufnet(blockCtx, wrapper.Listener, grpc.WithBlock())
	if err != nil {
		return fmt.Errorf("failed blocking dial to bufnet: %w", err)
	}
	defer blockCC.Close()
	if blockCC.GetState() != connectivity.Ready {
		return fmt.Errorf("expected state Ready with WithBlock, got %v", blockCC.GetState())
	}

	// 3. grpc.DialContext with grpc.WithBlock returns context.Canceled when context is already canceled
	canceledCtx, cancelNow := context.WithCancel(ctx)
	cancelNow()
	_, err = sample.DialBufnet(canceledCtx, wrapper.Listener, grpc.WithBlock())
	if err != context.Canceled {
		return fmt.Errorf("expected context.Canceled on canceled blocking dial, got %v", err)
	}

	return nil
}