github.com/sirupsen/logrus v1.4.2: 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 github.com/sirupsen/logrus.New in pkg:golang/github.com/sirupsen/logrus@v1.4.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/sirupsen/logrus@v1.4.2
Demonstrate these symbols/APIs:
  - github.com/sirupsen/logrus.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:sha256:0c61dced532d4359272cedd49675438e255aa571010549bcf43dbe0d7df0a418","contract":["logrus.New creates a non-nil Logger instance with default InfoLevel and TextFormatter","logrus.New creates a Logger that writes formatted log messages to the configured output writer","logrus.New creates a Logger that supports structured fields via WithField and WithFields","logrus.New creates a Logger whose level can be updated dynamically and checked via IsLevelEnabled","logrus.New creates a Logger that filters out log entries below the configured level"],"goal":"verify github.com/sirupsen/logrus.New in pkg:golang/github.com/sirupsen/logrus@v1.4.2","kind":"HOW","packages":["pkg:golang/github.com/sirupsen/logrus@v1.4.2"],"schemaVersion":1,"symbols":["github.com/sirupsen/logrus.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/github.com/sirupsen/logrus@v1.4.2"],"schemaVersion":1,"subject":"pkg:golang/github.com/sirupsen/logrus@v1.4.2","symbols":["github.com/sirupsen/logrus.New"],"verifierAdapter":"golang@1"}

module sample

go 1.22

require github.com/sirupsen/logrus v1.4.2

require (
	github.com/konsorten/go-windows-terminal-sequences v1.0.1 // indirect
	golang.org/x/sys v0.0.0-20190422165155-953cdadca894 // 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/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
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/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/pU5OE2C0WrNTOYK1Uuc=
golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

package main

import (
	"os"

	"github.com/sirupsen/logrus"
)

func main() {
	// Initialize a new logger instance
	logger := logrus.New()

	// Configure logger output and formatting
	logger.SetOutput(os.Stdout)
	logger.SetFormatter(&logrus.TextFormatter{
		DisableColors: true,
	})
	logger.SetLevel(logrus.InfoLevel)

	// Log with structured fields
	logger.WithFields(logrus.Fields{
		"event": "startup",
		"mode":  "production",
	}).Info("logger initialized successfully")
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/sirupsen/logrus.New in pkg:golang/github.com/sirupsen/logrus@v1.4.2",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/sirupsen/logrus@v1.4.2"
  ],
  "symbols": [
    "github.com/sirupsen/logrus.New"
  ]
}

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os"
	"strings"

	"github.com/sirupsen/logrus"
)

func main() {
	// Assertion 1: logrus.New creates a non-nil Logger instance with default InfoLevel and TextFormatter
	{
		logger := logrus.New()
		if logger == nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: logger is nil\n")
			os.Exit(1)
		}
		if logger.GetLevel() != logrus.InfoLevel {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected InfoLevel, got %v\n", logger.GetLevel())
			os.Exit(1)
		}
		if _, ok := logger.Formatter.(*logrus.TextFormatter); !ok {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected TextFormatter, got %T\n", logger.Formatter)
			os.Exit(1)
		}
	}

	// Assertion 2: logrus.New creates a Logger that writes formatted log messages to the configured output writer
	{
		var buf bytes.Buffer
		logger := logrus.New()
		logger.SetOutput(&buf)
		logger.SetFormatter(&logrus.TextFormatter{
			DisableColors:    true,
			DisableTimestamp: true,
		})

		logger.Info("contract test message")
		output := buf.String()
		if !strings.Contains(output, "level=info") {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: output missing level=info: %q\n", output)
			os.Exit(1)
		}
		if !strings.Contains(output, `msg="contract test message"`) {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: output missing msg: %q\n", output)
			os.Exit(1)
		}
	}

	// Assertion 3: logrus.New creates a Logger that supports structured fields via WithField and WithFields
	{
		var buf bytes.Buffer
		logger := logrus.New()
		logger.SetOutput(&buf)
		logger.SetFormatter(&logrus.JSONFormatter{})

		logger.WithField("component", "auth").WithFields(logrus.Fields{
			"user_id": 42,
			"action":  "login",
		}).Info("user authenticated")

		var parsed map[string]interface{}
		if err := json.Unmarshal(buf.Bytes(), &parsed); err != nil {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: json unmarshal: %v\n", err)
			os.Exit(1)
		}
		if parsed["component"] != "auth" {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: component mismatch: %v\n", parsed["component"])
			os.Exit(1)
		}
		if parsed["user_id"] != float64(42) {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: user_id mismatch: %v\n", parsed["user_id"])
			os.Exit(1)
		}
		if parsed["action"] != "login" {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: action mismatch: %v\n", parsed["action"])
			os.Exit(1)
		}
		if parsed["msg"] != "user authenticated" {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: msg mismatch: %v\n", parsed["msg"])
			os.Exit(1)
		}
		if parsed["level"] != "info" {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: level mismatch: %v\n", parsed["level"])
			os.Exit(1)
		}
	}

	// Assertion 4: logrus.New creates a Logger whose level can be updated dynamically and checked via IsLevelEnabled
	{
		logger := logrus.New()
		logger.SetLevel(logrus.WarnLevel)
		if logger.GetLevel() != logrus.WarnLevel {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: expected WarnLevel, got %v\n", logger.GetLevel())
			os.Exit(1)
		}
		if logger.IsLevelEnabled(logrus.DebugLevel) {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: DebugLevel should not be enabled when level is Warn\n")
			os.Exit(1)
		}
		if logger.IsLevelEnabled(logrus.InfoLevel) {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: InfoLevel should not be enabled when level is Warn\n")
			os.Exit(1)
		}
		if !logger.IsLevelEnabled(logrus.WarnLevel) {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: WarnLevel should be enabled\n")
			os.Exit(1)
		}
		if !logger.IsLevelEnabled(logrus.ErrorLevel) {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: ErrorLevel should be enabled\n")
			os.Exit(1)
		}
	}

	// Assertion 5: logrus.New creates a Logger that filters out log entries below the configured level
	{
		var buf bytes.Buffer
		logger := logrus.New()
		logger.SetOutput(&buf)
		logger.SetLevel(logrus.WarnLevel)

		logger.Debug("debug message")
		logger.Info("info message")
		if buf.Len() != 0 {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: filtered logs produced output: %q\n", buf.String())
			os.Exit(1)
		}

		logger.Warn("warn message")
		if buf.Len() == 0 {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: warn message produced no output\n")
			os.Exit(1)
		}
	}

	fmt.Println("PASS: all logrus.New contract assertions passed.")
}