github.com/go-logr/logr v1.4.1: funcr.NewJSON

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 github.com/go-logr/logr/funcr.NewJSON in pkg:golang/github.com/go-logr/logr@v1.4.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/go-logr/logr@v1.4.1
Demonstrate these symbols/APIs:
  - github.com/go-logr/logr/funcr.NewJSON

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:sha256:35039969bdbddfa17158b058843898115459a7427b9770e9e80c9696ebd97cd7","contract":["funcr.NewJSON creates a logr.Logger that serializes structured log messages and key-value arguments to JSON via a custom write sink.","funcr.NewJSON formats error messages under the 'error' key and structured message strings under the 'msg' key.","funcr.NewJSON preserves contextual logger names and key-value pairs added through WithName and WithValues.","funcr.NewJSON filters log messages by verbosity level using Options.Verbosity and logger.V()."],"goal":"verify github.com/go-logr/logr/funcr.NewJSON in pkg:golang/github.com/go-logr/logr@v1.4.1","kind":"HOW","packages":["pkg:golang/github.com/go-logr/logr@v1.4.1"],"schemaVersion":1,"symbols":["github.com/go-logr/logr/funcr.NewJSON"]},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","executionContext":"go","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","runtime":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/go-logr/logr@v1.4.1"],"schemaVersion":1,"subject":"pkg:golang/github.com/go-logr/logr@v1.4.1","symbols":["github.com/go-logr/logr/funcr.NewJSON"],"verifierAdapter":"golang@1"}

package funcrjson_test

import (
	"encoding/json"
	"errors"
	"testing"

	"github.com/go-logr/logr"
	"github.com/go-logr/logr/funcr"
)

func TestFuncrNewJSONBasic(t *testing.T) {
	var logged []string
	sink := func(obj string) {
		logged = append(logged, obj)
	}

	var logger logr.Logger = funcr.NewJSON(sink, funcr.Options{})

	logger.Info("service initialized", "port", 8080, "protocol", "tcp")

	if len(logged) != 1 {
		t.Fatalf("expected 1 log entry, got %d", len(logged))
	}

	var data map[string]interface{}
	if err := json.Unmarshal([]byte(logged[0]), &data); err != nil {
		t.Fatalf("failed to unmarshal JSON log: %v", err)
	}

	if data["msg"] != "service initialized" {
		t.Errorf("expected msg 'service initialized', got %v", data["msg"])
	}
	if data["port"] != float64(8080) {
		t.Errorf("expected port 8080, got %v", data["port"])
	}
	if data["protocol"] != "tcp" {
		t.Errorf("expected protocol 'tcp', got %v", data["protocol"])
	}
}

func TestFuncrNewJSONError(t *testing.T) {
	var logged []string
	sink := func(obj string) {
		logged = append(logged, obj)
	}

	var logger logr.Logger = funcr.NewJSON(sink, funcr.Options{})

	sampleErr := errors.New("connection reset by peer")
	logger.Error(sampleErr, "failed to handle request", "retry", 3)

	if len(logged) != 1 {
		t.Fatalf("expected 1 log entry, got %d", len(logged))
	}

	var data map[string]interface{}
	if err := json.Unmarshal([]byte(logged[0]), &data); err != nil {
		t.Fatalf("failed to unmarshal JSON log: %v", err)
	}

	if data["msg"] != "failed to handle request" {
		t.Errorf("expected msg 'failed to handle request', got %v", data["msg"])
	}
	if data["error"] != "connection reset by peer" {
		t.Errorf("expected error 'connection reset by peer', got %v", data["error"])
	}
	if data["retry"] != float64(3) {
		t.Errorf("expected retry 3, got %v", data["retry"])
	}
}

func TestFuncrNewJSONWithValuesAndName(t *testing.T) {
	var logged []string
	sink := func(obj string) {
		logged = append(logged, obj)
	}

	var baseLogger logr.Logger = funcr.NewJSON(sink, funcr.Options{})
	namedLogger := baseLogger.WithName("authService").WithValues("tenantId", "tenant-123")

	namedLogger.Info("user authentication successful", "userId", "user-456")

	if len(logged) != 1 {
		t.Fatalf("expected 1 log entry, got %d", len(logged))
	}

	var data map[string]interface{}
	if err := json.Unmarshal([]byte(logged[0]), &data); err != nil {
		t.Fatalf("failed to unmarshal JSON log: %v", err)
	}

	if data["logger"] != "authService" {
		t.Errorf("expected logger 'authService', got %v", data["logger"])
	}
	if data["tenantId"] != "tenant-123" {
		t.Errorf("expected tenantId 'tenant-123', got %v", data["tenantId"])
	}
	if data["userId"] != "user-456" {
		t.Errorf("expected userId 'user-456', got %v", data["userId"])
	}
	if data["msg"] != "user authentication successful" {
		t.Errorf("expected msg 'user authentication successful', got %v", data["msg"])
	}
}

func TestFuncrNewJSONVerbosity(t *testing.T) {
	var logged []string
	sink := func(obj string) {
		logged = append(logged, obj)
	}

	var logger logr.Logger = funcr.NewJSON(sink, funcr.Options{Verbosity: 1})

	logger.V(0).Info("info level 0")
	logger.V(1).Info("debug level 1")
	logger.V(2).Info("trace level 2 (discarded)")

	if len(logged) != 2 {
		t.Fatalf("expected 2 logged entries, got %d", len(logged))
	}

	var entry1, entry2 map[string]interface{}
	if err := json.Unmarshal([]byte(logged[0]), &entry1); err != nil {
		t.Fatalf("failed to parse JSON: %v", err)
	}
	if err := json.Unmarshal([]byte(logged[1]), &entry2); err != nil {
		t.Fatalf("failed to parse JSON: %v", err)
	}

	if entry1["msg"] != "info level 0" {
		t.Errorf("entry 1 msg mismatch: %v", entry1["msg"])
	}
	if entry2["msg"] != "debug level 1" {
		t.Errorf("entry 2 msg mismatch: %v", entry2["msg"])
	}
	if entry2["level"] != float64(1) {
		t.Errorf("expected level 1, got %v", entry2["level"])
	}
}

module example.com/funcrjson

go 1.22

require github.com/go-logr/logr v1.4.1

github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ=
github.com/go-logr/logr v1.4.1/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=

{
  "schemaVersion": 1,
  "goal": "verify github.com/go-logr/logr/funcr.NewJSON in pkg:golang/github.com/go-logr/logr@v1.4.1",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/go-logr/logr@v1.4.1"
  ],
  "symbols": [
    "github.com/go-logr/logr/funcr.NewJSON"
  ]
}