github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f

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/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f

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:f7bee6a4c5f479dd481c21b2226521322afb1d2b7b04340fad72264dc96106c9","contract":["DialNameToContext sets dialer name in context and DialNameFromContext retrieves it","PreRegisterDialerMetrics pre-allocates Prometheus metrics without error","NewListener wraps net.Listener with connection tracking options","NewDialContextFunc dials tracked TCP listener and exchanges data over context-aware connection","NewDialFunc dials tracked TCP listener and executes connection tracking"],"goal":"verify pkg:golang/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f","kind":"HOW","packages":["pkg:golang/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f"],"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/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f"],"schemaVersion":1,"subject":"pkg:golang/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f","verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f

require (
	github.com/beorn7/perks v1.0.1 // indirect
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	github.com/jpillora/backoff v1.0.0 // indirect
	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
	github.com/prometheus/client_golang v1.24.1 // indirect
	github.com/prometheus/client_model v0.6.2 // indirect
	github.com/prometheus/common v0.70.1 // indirect
	github.com/prometheus/procfs v0.21.1 // indirect
	golang.org/x/net v0.59.0 // indirect
	golang.org/x/sys v0.48.0 // indirect
	google.golang.org/protobuf v1.36.11 // indirect
)

github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
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/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f h1:KUppIJq7/+SVif2QVs3tOP0zanoHgBEVAwHxUSIzRqU=
github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/prometheus/client_golang v1.24.1 h1:JnJkREXzWxUdCuPFpIWZiPispT9xVV59uiuyR2bPlnU=
github.com/prometheus/client_golang v1.24.1/go.mod h1:F+oSRECHg4sse5ucfYpYDeIv/hu68Zo0uoHKetWnzcE=
github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvMVzSfMLjcu6wAwpE=
github.com/prometheus/common v0.70.1 h1:1HvjP4D5oL3t8RsPlwxA9onvvStjtIHYE5XuuwOi/PY=
github.com/prometheus/common v0.70.1/go.mod h1:VdFUQDMZK3VLkurFUVhia6uys/0suUp86TJz5qbJRhc=
github.com/prometheus/procfs v0.21.1 h1:GljZCt+zSTS+NZq88cyQ1LjZ+RCHp3uVuabBWA5+OJI=
github.com/prometheus/procfs v0.21.1/go.mod h1:aB55Cww9pdSJVHk0hUf0inxWyyjPogFIjmHKYgMKmtY=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
go.yaml.in/yaml/v2 v2.4.4 h1:tuyd0P+2Ont/d6e2rl3be67goVK4R6deVxCUX5vyPaQ=
go.yaml.in/yaml/v2 v2.4.4/go.mod h1:gMZqIpDtDqOfM0uNfy0SkpRhvUryYH0Z6wdMYcacYXQ=
golang.org/x/net v0.59.0 h1:5zfYln+w5XCxwrnMMJPufRgNoXEaGxl0wo5GqPXyues=
golang.org/x/net v0.59.0/go.mod h1:2DA/G1UfVbCpQPeWTmMPGY7Cs2PkBkwu743bVX5PIVg=
golang.org/x/sys v0.48.0 h1:bbX/i/6MgT9BVLM9RT1thmxL04yeTAhbEz4SyadbXoo=
golang.org/x/sys v0.48.0/go.mod h1:hNLxWAXmnKAxqDtdwIYC4bM9oQPEecfsnNMuSxOs3og=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"context"
	"fmt"
	"io"
	"net"
	"time"

	"github.com/mwitkow/go-conntrack"
)

func main() {
	// Pre-register dialer metrics
	conntrack.PreRegisterDialerMetrics("example_client")

	// Associate dialer name with context
	ctx := conntrack.DialNameToContext(context.Background(), "example_client")
	fmt.Printf("Dialer name from context: %s\n", conntrack.DialNameFromContext(ctx))

	// Create local TCP listener tracked by conntrack
	rawListener, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		panic(err)
	}
	defer rawListener.Close()

	trackedListener := conntrack.NewListener(
		rawListener,
		conntrack.TrackWithName("example_server"),
		conntrack.TrackWithTcpKeepAlive(10*time.Second),
	)
	defer trackedListener.Close()

	// Server accept goroutine
	done := make(chan struct{})
	go func() {
		defer close(done)
		conn, err := trackedListener.Accept()
		if err != nil {
			return
		}
		defer conn.Close()

		buf := make([]byte, 128)
		n, err := conn.Read(buf)
		if err != nil && err != io.EOF {
			return
		}
		_, _ = conn.Write(append([]byte("echo: "), buf[:n]...))
	}()

	// Connect using NewDialContextFunc
	dialCtx := conntrack.NewDialContextFunc(
		conntrack.DialWithName("example_client"),
	)

	clientConn, err := dialCtx(ctx, "tcp", trackedListener.Addr().String())
	if err != nil {
		panic(err)
	}
	defer clientConn.Close()

	if _, err := clientConn.Write([]byte("ping")); err != nil {
		panic(err)
	}

	reply := make([]byte, 128)
	n, err := clientConn.Read(reply)
	if err != nil {
		panic(err)
	}
	fmt.Printf("Received: %s\n", string(reply[:n]))

	<-done
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/mwitkow/go-conntrack@v0.0.0-20190716064945-2f068394615f"
  ]
}

package main

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

	"github.com/mwitkow/go-conntrack"
)

func main() {
	// Assertion 1: DialNameToContext sets dialer name in context and DialNameFromContext retrieves it
	{
		baseCtx := context.Background()
		if name := conntrack.DialNameFromContext(baseCtx); name != "" {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected empty dialer name, got %q\n", name)
			os.Exit(1)
		}
		ctx := conntrack.DialNameToContext(baseCtx, "test_dialer")
		if name := conntrack.DialNameFromContext(ctx); name != "test_dialer" {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected test_dialer, got %q\n", name)
			os.Exit(1)
		}
	}

	// Assertion 2: PreRegisterDialerMetrics pre-allocates Prometheus metrics without error
	{
		conntrack.PreRegisterDialerMetrics("contract_dialer")
	}

	// Assertion 3: NewListener wraps net.Listener with connection tracking options
	{
		rawLn, err := net.Listen("tcp", "127.0.0.1:0")
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: net.Listen error: %v\n", err)
			os.Exit(1)
		}
		defer rawLn.Close()

		trackedLn := conntrack.NewListener(
			rawLn,
			conntrack.TrackWithName("contract_listener"),
			conntrack.TrackWithTcpKeepAlive(5*time.Second),
		)
		if trackedLn == nil {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: expected non-nil listener\n")
			os.Exit(1)
		}
		if trackedLn.Addr().String() != rawLn.Addr().String() {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: address mismatch: %s vs %s\n", trackedLn.Addr(), rawLn.Addr())
			os.Exit(1)
		}
		_ = trackedLn.Close()
	}

	// Assertion 4: NewDialContextFunc dials tracked TCP listener and exchanges data over context-aware connection
	{
		rawLn, err := net.Listen("tcp", "127.0.0.1:0")
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: net.Listen error: %v\n", err)
			os.Exit(1)
		}
		defer rawLn.Close()

		trackedLn := conntrack.NewListener(rawLn, conntrack.TrackWithName("srv_ctx"))
		defer trackedLn.Close()

		errCh := make(chan error, 1)
		go func() {
			conn, err := trackedLn.Accept()
			if err != nil {
				errCh <- err
				return
			}
			defer conn.Close()

			buf := make([]byte, 4)
			if _, err := io.ReadFull(conn, buf); err != nil {
				errCh <- err
				return
			}
			if string(buf) != "PING" {
				errCh <- fmt.Errorf("unexpected payload: %s", string(buf))
				return
			}
			if _, err := conn.Write([]byte("PONG")); err != nil {
				errCh <- err
				return
			}
			errCh <- nil
		}()

		dialCtx := conntrack.NewDialContextFunc(conntrack.DialWithName("cli_ctx"))
		ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
		defer cancel()

		conn, err := dialCtx(ctx, "tcp", trackedLn.Addr().String())
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: dialCtx error: %v\n", err)
			os.Exit(1)
		}
		defer conn.Close()

		if _, err := conn.Write([]byte("PING")); err != nil {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: client write error: %v\n", err)
			os.Exit(1)
		}

		resp := make([]byte, 4)
		if _, err := io.ReadFull(conn, resp); err != nil {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: client read error: %v\n", err)
			os.Exit(1)
		}
		if string(resp) != "PONG" {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: expected PONG, got %s\n", string(resp))
			os.Exit(1)
		}

		if err := <-errCh; err != nil {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: server error: %v\n", err)
			os.Exit(1)
		}
	}

	// Assertion 5: NewDialFunc dials tracked TCP listener and executes connection tracking
	{
		rawLn, err := net.Listen("tcp", "127.0.0.1:0")
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: net.Listen error: %v\n", err)
			os.Exit(1)
		}
		defer rawLn.Close()

		trackedLn := conntrack.NewListener(rawLn, conntrack.TrackWithName("srv_dial"))
		defer trackedLn.Close()

		errCh := make(chan error, 1)
		go func() {
			conn, err := trackedLn.Accept()
			if err != nil {
				errCh <- err
				return
			}
			defer conn.Close()
			_, err = conn.Write([]byte("OK"))
			errCh <- err
		}()

		dial := conntrack.NewDialFunc(conntrack.DialWithName("cli_dial"))
		conn, err := dial("tcp", trackedLn.Addr().String())
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: dial error: %v\n", err)
			os.Exit(1)
		}
		defer conn.Close()

		buf := make([]byte, 2)
		if _, err := io.ReadFull(conn, buf); err != nil {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: read error: %v\n", err)
			os.Exit(1)
		}
		if string(buf) != "OK" {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: expected OK, got %s\n", string(buf))
			os.Exit(1)
		}
		if err := <-errCh; err != nil {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: server error: %v\n", err)
			os.Exit(1)
		}
	}

	fmt.Println("All contract assertions passed successfully.")
}