github.com/sirupsen/logrus v1.10.2: FatalLevel

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.FatalLevel in pkg:golang/github.com/sirupsen/logrus@v1.10.2
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/sirupsen/logrus@v1.10.2
Demonstrate these symbols/APIs:
  - github.com/sirupsen/logrus.FatalLevel

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:sha256:4eb81b8b3146945b92ee9995d32c56cb3921f2534a0656be0a8f8d83b018bbac","contract":["FatalLevel is a distinct logrus Level constant with string representation fatal","ParseLevel parses case-insensitive fatal strings into FatalLevel","FatalLevel supports text marshaling and unmarshaling","Logger level filtering respects FatalLevel threshold hierarchy","Fatal logging triggers custom ExitFunc and dispatches to registered FatalLevel hooks"],"goal":"verify github.com/sirupsen/logrus.FatalLevel in pkg:golang/github.com/sirupsen/logrus@v1.10.2","kind":"HOW","packages":["pkg:golang/github.com/sirupsen/logrus@v1.10.2"],"schemaVersion":1,"symbols":["github.com/sirupsen/logrus.FatalLevel"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/sirupsen/logrus@v1.10.2"],"schemaVersion":1,"subject":"pkg:golang/github.com/sirupsen/logrus@v1.10.2","symbols":["github.com/sirupsen/logrus.FatalLevel"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/sirupsen/logrus v1.10.2

require golang.org/x/sys v0.13.0 // indirect

github.com/sirupsen/logrus v1.10.2 h1:G2SED73/qrAu6YwbdxOD6peLkCBI3z7L+ykJFTXJBBo=
github.com/sirupsen/logrus v1.10.2/go.mod h1:SLEg8TqYulVKKfIGHldVp2K2aYz2DKSVBq4g/H5bR7Q=
github.com/stretchr/testify v1.12.1 h1:EuwCh5fleGS7H32xRwO3wRGT7DxrDhLAT6FF8MpWDWE=
github.com/stretchr/testify v1.12.1/go.mod h1:MDEgiDPPsNp5cuIrHPPCyornHKgEVbtFUmoNlxoYthg=
go.yaml.in/yaml/v3 v3.0.5 h1:N6y/pJk8buWs9NY5ERU2HSMfm+IuD/OtfdAnq6kESPw=
go.yaml.in/yaml/v3 v3.0.5/go.mod h1:HVTZu1O7/Vkt2N+BFy8Zza+lnLsABggaTM2ZpNIGuKg=
golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

{
  "schemaVersion": 1,
  "goal": "verify github.com/sirupsen/logrus.FatalLevel in pkg:golang/github.com/sirupsen/logrus@v1.10.2",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/sirupsen/logrus@v1.10.2"
  ],
  "symbols": [
    "github.com/sirupsen/logrus.FatalLevel"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"
	"strings"

	"github.com/sirupsen/logrus"
)

type fatalHook struct {
	fired   bool
	level   logrus.Level
	message string
}

func (h *fatalHook) Levels() []logrus.Level {
	return []logrus.Level{logrus.FatalLevel}
}

func (h *fatalHook) Fire(entry *logrus.Entry) error {
	h.fired = true
	h.level = entry.Level
	h.message = entry.Message
	return nil
}

func main() {
	if err := runTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All contract tests passed successfully.")
}

func runTests() error {
	// 1. FatalLevel is a distinct logrus Level constant with string representation "fatal"
	if logrus.FatalLevel.String() != "fatal" {
		return fmt.Errorf("expected FatalLevel.String() == 'fatal', got %q", logrus.FatalLevel.String())
	}
	if logrus.FatalLevel != logrus.Level(1) {
		return fmt.Errorf("expected FatalLevel value 1, got %d", logrus.FatalLevel)
	}

	// 2. ParseLevel parses case-insensitive strings into FatalLevel
	for _, input := range []string{"fatal", "FATAL", "Fatal"} {
		parsed, err := logrus.ParseLevel(input)
		if err != nil {
			return fmt.Errorf("failed to parse level %q: %w", input, err)
		}
		if parsed != logrus.FatalLevel {
			return fmt.Errorf("parsed %q expected FatalLevel, got %v", input, parsed)
		}
	}

	// 3. FatalLevel supports text marshaling and unmarshaling
	data, err := logrus.FatalLevel.MarshalText()
	if err != nil {
		return fmt.Errorf("failed to marshal FatalLevel: %w", err)
	}
	if string(data) != "fatal" {
		return fmt.Errorf("marshaled text mismatch: expected 'fatal', got %q", string(data))
	}
	var unmarshaled logrus.Level
	if err := unmarshaled.UnmarshalText([]byte("fatal")); err != nil {
		return fmt.Errorf("failed to unmarshal FatalLevel: %w", err)
	}
	if unmarshaled != logrus.FatalLevel {
		return fmt.Errorf("unmarshaled mismatch: expected FatalLevel, got %v", unmarshaled)
	}

	// 4. Logger level filtering respects FatalLevel threshold hierarchy
	logger := logrus.New()
	var buf bytes.Buffer
	logger.SetOutput(&buf)
	logger.SetLevel(logrus.FatalLevel)

	if logger.GetLevel() != logrus.FatalLevel {
		return fmt.Errorf("expected logger level FatalLevel, got %v", logger.GetLevel())
	}
	if !logger.IsLevelEnabled(logrus.PanicLevel) {
		return fmt.Errorf("expected PanicLevel enabled when level is FatalLevel")
	}
	if !logger.IsLevelEnabled(logrus.FatalLevel) {
		return fmt.Errorf("expected FatalLevel enabled when level is FatalLevel")
	}
	if logger.IsLevelEnabled(logrus.ErrorLevel) {
		return fmt.Errorf("expected ErrorLevel disabled when level is FatalLevel")
	}
	if logger.IsLevelEnabled(logrus.InfoLevel) {
		return fmt.Errorf("expected InfoLevel disabled when level is FatalLevel")
	}

	// 5. Fatal logging triggers custom ExitFunc and dispatches to registered FatalLevel hooks
	hook := &fatalHook{}
	logger.AddHook(hook)

	var exitCode int
	var exitCalled bool
	logger.ExitFunc = func(code int) {
		exitCalled = true
		exitCode = code
	}

	testMsg := "critical system component failed"
	logger.Fatal(testMsg)

	if !exitCalled {
		return fmt.Errorf("expected ExitFunc to be called on Fatal")
	}
	if exitCode != 1 {
		return fmt.Errorf("expected exit code 1, got %d", exitCode)
	}
	if !hook.fired {
		return fmt.Errorf("expected FatalLevel hook to fire")
	}
	if hook.level != logrus.FatalLevel {
		return fmt.Errorf("hook captured level mismatch: expected FatalLevel, got %v", hook.level)
	}
	if hook.message != testMsg {
		return fmt.Errorf("hook captured message mismatch: expected %q, got %q", testMsg, hook.message)
	}
	output := buf.String()
	if !strings.Contains(output, testMsg) {
		return fmt.Errorf("expected log output to contain message %q, got: %s", testMsg, output)
	}
	if !strings.Contains(output, "level=fatal") {
		return fmt.Errorf("expected log output to contain 'level=fatal', got: %s", output)
	}

	return nil
}