go.uber.org/zap v1.28.0: New

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 go.uber.org/zap.New in pkg:golang/go.uber.org/zap@v1.28.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.uber.org/zap@v1.28.0
Demonstrate these symbols/APIs:
  - go.uber.org/zap.New

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:b879b3dc4021a6b74db35e278c5cff65c93c7d10e037098356fa68ce303a776f","contract":["zap.New initializes a Logger with base zap.Fields that are included in every emitted log entry","zap.New with zap.Hooks executes registered callbacks on each logged entry","zap.New with zap.AddCaller records caller file and line location for logged entries","zap.New with nil core returns a safe no-op logger that does not panic on log calls"],"goal":"verify go.uber.org/zap.New in pkg:golang/go.uber.org/zap@v1.28.0","kind":"HOW","packages":["pkg:golang/go.uber.org/zap@v1.28.0"],"schemaVersion":1,"symbols":["go.uber.org/zap.New"]},"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/go.uber.org/zap@v1.28.0"],"schemaVersion":1,"subject":"pkg:golang/go.uber.org/zap@v1.28.0","symbols":["go.uber.org/zap.New"],"verifierAdapter":"golang@1"}

module sample

go 1.23

require go.uber.org/zap v1.28.0

require go.uber.org/multierr v1.10.0 // indirect

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/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
go.uber.org/zap v1.28.0 h1:IZzaP1Fv73/T/pBMLk4VutPl36uNC+OSUh3JLG3FIjo=
go.uber.org/zap v1.28.0/go.mod h1:rDLpOi171uODNm/mxFcuYWxDsqWSAVkFdX4XojSKg/Q=
go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package sample

import (
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

// NewLogger constructs a zap.Logger wrapping the core with optional settings.
func NewLogger(core zapcore.Core, options ...zap.Option) *zap.Logger {
	return zap.New(core, options...)
}

// NewLoggerWithHook constructs a zap.Logger with an attached entry hook.
func NewLoggerWithHook(core zapcore.Core, hook func(zapcore.Entry) error, options ...zap.Option) *zap.Logger {
	opts := append([]zap.Option{zap.Hooks(hook)}, options...)
	return zap.New(core, opts...)
}

{
  "schemaVersion": 1,
  "goal": "verify go.uber.org/zap.New in pkg:golang/go.uber.org/zap@v1.28.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.uber.org/zap@v1.28.0"
  ],
  "symbols": [
    "go.uber.org/zap.New"
  ]
}

package main

import (
	"fmt"
	"os"

	"sample"

	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
	"go.uber.org/zap/zaptest/observer"
)

func main() {
	// 1. zap.New initializes a Logger with base zap.Fields that are included in every emitted log entry
	core1, logs1 := observer.New(zapcore.InfoLevel)
	logger1 := sample.NewLogger(core1, zap.Fields(zap.String("service", "auth-service")))
	logger1.Info("user login", zap.String("user", "alice"))

	entries1 := logs1.All()
	if len(entries1) != 1 {
		fmt.Fprintf(os.Stderr, "contract failed: expected 1 log entry, got %d\n", len(entries1))
		os.Exit(1)
	}
	ctx1 := entries1[0].ContextMap()
	if ctx1["service"] != "auth-service" {
		fmt.Fprintf(os.Stderr, "contract failed: missing or invalid 'service' field: %#v\n", ctx1)
		os.Exit(1)
	}
	if ctx1["user"] != "alice" {
		fmt.Fprintf(os.Stderr, "contract failed: missing or invalid 'user' field: %#v\n", ctx1)
		os.Exit(1)
	}

	// 2. zap.New with zap.Hooks executes registered callbacks on each logged entry
	core2, _ := observer.New(zapcore.InfoLevel)
	var hookedMessages []string
	hook := func(entry zapcore.Entry) error {
		hookedMessages = append(hookedMessages, entry.Message)
		return nil
	}
	logger2 := sample.NewLoggerWithHook(core2, hook)
	logger2.Info("first event")
	logger2.Info("second event")
	if len(hookedMessages) != 2 || hookedMessages[0] != "first event" || hookedMessages[1] != "second event" {
		fmt.Fprintf(os.Stderr, "contract failed: hook was not called properly: %#v\n", hookedMessages)
		os.Exit(1)
	}

	// 3. zap.New with zap.AddCaller records caller file and line location for logged entries
	core3, logs3 := observer.New(zapcore.InfoLevel)
	logger3 := sample.NewLogger(core3, zap.AddCaller())
	logger3.Info("caller test")
	entries3 := logs3.All()
	if len(entries3) != 1 {
		fmt.Fprintf(os.Stderr, "contract failed: expected 1 log entry, got %d\n", len(entries3))
		os.Exit(1)
	}
	if !entries3[0].Caller.Defined {
		fmt.Fprintf(os.Stderr, "contract failed: caller is not defined\n")
		os.Exit(1)
	}
	if entries3[0].Caller.File == "" || entries3[0].Caller.Line == 0 {
		fmt.Fprintf(os.Stderr, "contract failed: caller file or line empty: %#v\n", entries3[0].Caller)
		os.Exit(1)
	}

	// 4. zap.New with nil core returns a safe no-op logger that does not panic on log calls
	logger4 := sample.NewLogger(nil)
	if logger4 == nil {
		fmt.Fprintf(os.Stderr, "contract failed: zap.New(nil) returned nil logger\n")
		os.Exit(1)
	}
	logger4.Debug("nop debug")
	logger4.Info("nop info")
	logger4.Warn("nop warn")
	logger4.Error("nop error")

	fmt.Println("PASS")
}