github.com/sirupsen/logrus v1.4.2: Logger

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.Logger 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.Logger

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:e4083dddfe8b0efb00ddd9fd8f944bfc1c6005cb077af6029821631c60269d58","contract":["logrus.Logger can be instantiated directly or via logrus.New","logrus.Logger configures output destination via SetOutput and writes messages","logrus.Logger formats output according to configured Formatter","logrus.Logger manages log levels via SetLevel, GetLevel, and IsLevelEnabled","logrus.Logger creates structured log entries via WithField and WithFields"],"goal":"verify github.com/sirupsen/logrus.Logger 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.Logger"]},"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.Logger"],"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() {
	// Instantiate a logrus.Logger directly or with logrus.New()
	logger := logrus.New()

	// Configure output destination, formatter, and logging level on Logger
	logger.SetOutput(os.Stdout)
	logger.SetFormatter(&logrus.TextFormatter{
		DisableColors: true,
	})
	logger.SetLevel(logrus.InfoLevel)

	// Emit structured logs using WithField and WithFields
	logger.WithField("subsystem", "worker").WithFields(logrus.Fields{
		"event":  "initialization",
		"status": "ready",
	}).Info("logrus.Logger configured successfully")
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/sirupsen/logrus.Logger 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.Logger"
  ]
}

package main

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

	"github.com/sirupsen/logrus"
)

func main() {
	// Assertion 1: logrus.Logger can be instantiated directly or via logrus.New
	{
		newLogger := logrus.New()
		if newLogger == nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: logrus.New returned nil\n")
			os.Exit(1)
		}

		directLogger := &logrus.Logger{
			Out:       os.Stderr,
			Formatter: new(logrus.TextFormatter),
			Hooks:     make(logrus.LevelHooks),
			Level:     logrus.DebugLevel,
		}
		if directLogger == nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: direct logger is nil\n")
			os.Exit(1)
		}
		if directLogger.Level != logrus.DebugLevel {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: direct logger level mismatch\n")
			os.Exit(1)
		}
	}

	// Assertion 2: logrus.Logger configures output destination via SetOutput and writes messages
	{
		var buf bytes.Buffer
		logger := logrus.New()
		logger.SetOutput(&buf)
		logger.SetFormatter(&logrus.TextFormatter{
			DisableColors:    true,
			DisableTimestamp: true,
		})

		logger.Info("contract test line")
		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 line"`) {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: output missing msg: %q\n", output)
			os.Exit(1)
		}
	}

	// Assertion 3: logrus.Logger formats output according to configured Formatter
	{
		var buf bytes.Buffer
		logger := logrus.New()
		logger.SetOutput(&buf)
		logger.SetFormatter(&logrus.JSONFormatter{})

		logger.Info("contract json format")

		var parsed map[string]interface{}
		if err := json.Unmarshal(buf.Bytes(), &parsed); err != nil {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: json unmarshal error: %v\n", err)
			os.Exit(1)
		}
		if parsed["msg"] != "contract json format" {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: unexpected msg: %v\n", parsed["msg"])
			os.Exit(1)
		}
		if parsed["level"] != "info" {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: unexpected level: %v\n", parsed["level"])
			os.Exit(1)
		}
	}

	// Assertion 4: logrus.Logger manages log levels via SetLevel, GetLevel, and IsLevelEnabled
	{
		var buf bytes.Buffer
		logger := logrus.New()
		logger.SetOutput(&buf)
		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\n")
			os.Exit(1)
		}
		if logger.IsLevelEnabled(logrus.InfoLevel) {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: InfoLevel should not be enabled\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)
		}

		logger.Info("info message below threshold")
		if buf.Len() != 0 {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: filtered level produced output: %q\n", buf.String())
			os.Exit(1)
		}

		logger.Warn("warn message at threshold")
		if buf.Len() == 0 {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: warn message produced no output\n")
			os.Exit(1)
		}
	}

	// Assertion 5: logrus.Logger creates structured log entries via WithField and WithFields
	{
		var buf bytes.Buffer
		logger := logrus.New()
		logger.SetOutput(&buf)
		logger.SetFormatter(&logrus.JSONFormatter{})

		logger.WithField("subsystem", "auth").WithFields(logrus.Fields{
			"user_id": 1001,
			"active":  true,
		}).Info("user session established")

		var parsed map[string]interface{}
		if err := json.Unmarshal(buf.Bytes(), &parsed); err != nil {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: json unmarshal error: %v\n", err)
			os.Exit(1)
		}
		if parsed["subsystem"] != "auth" {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: subsystem mismatch: %v\n", parsed["subsystem"])
			os.Exit(1)
		}
		if parsed["user_id"] != float64(1001) {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: user_id mismatch: %v\n", parsed["user_id"])
			os.Exit(1)
		}
		if parsed["active"] != true {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: active mismatch: %v\n", parsed["active"])
			os.Exit(1)
		}
		if parsed["msg"] != "user session established" {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: msg mismatch: %v\n", parsed["msg"])
			os.Exit(1)
		}
		if parsed["level"] != "info" {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: level mismatch: %v\n", parsed["level"])
			os.Exit(1)
		}
	}

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