github.com/sirupsen/logrus v1.9.3: LevelHooks

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.LevelHooks in pkg:golang/github.com/sirupsen/logrus@v1.9.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/sirupsen/logrus@v1.9.3
Demonstrate these symbols/APIs:
  - github.com/sirupsen/logrus.LevelHooks

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:cd5444e5fde7e2092a58a8fd6ca2095898c774d2677a1262524ca00ed65e58b4","contract":["LevelHooks.Add registers a hook for each log level specified by Hook.Levels","LevelHooks.Fire executes registered hooks for the specified log level","LevelHooks.Fire does not execute hooks registered for other log levels","LevelHooks.Fire returns the error returned by a hook and halts further hook execution","LevelHooks.Fire executes multiple hooks registered for the same level in insertion order"],"goal":"verify github.com/sirupsen/logrus.LevelHooks in pkg:golang/github.com/sirupsen/logrus@v1.9.3","kind":"HOW","packages":["pkg:golang/github.com/sirupsen/logrus@v1.9.3"],"schemaVersion":1,"symbols":["github.com/sirupsen/logrus.LevelHooks"]},"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@v1.9.3"],"schemaVersion":1,"subject":"pkg:golang/github.com/sirupsen/logrus@v1.9.3","symbols":["github.com/sirupsen/logrus.LevelHooks"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/sirupsen/logrus v1.9.3

require golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect

github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
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/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"fmt"
	"io"

	"github.com/sirupsen/logrus"
)

type counterHook struct {
	firedCount int
}

func (h *counterHook) Levels() []logrus.Level {
	return []logrus.Level{logrus.InfoLevel, logrus.WarnLevel}
}

func (h *counterHook) Fire(entry *logrus.Entry) error {
	h.firedCount++
	entry.Data["hook_invoked"] = true
	return nil
}

func main() {
	logger := logrus.New()
	logger.SetOutput(io.Discard)

	hook := &counterHook{}
	logger.Hooks.Add(hook)

	logger.Info("Demonstrating logrus LevelHooks")
	fmt.Printf("Hook fired count: %d\n", hook.firedCount)
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/sirupsen/logrus.LevelHooks in pkg:golang/github.com/sirupsen/logrus@v1.9.3",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/sirupsen/logrus@v1.9.3"
  ],
  "symbols": [
    "github.com/sirupsen/logrus.LevelHooks"
  ]
}

package main

import (
	"errors"
	"fmt"
	"io"
	"os"

	"github.com/sirupsen/logrus"
)

type recordingHook struct {
	levels      []logrus.Level
	callCount   int
	errToReturn error
	id          string
	orderRef    *[]string
}

func (h *recordingHook) Levels() []logrus.Level {
	return h.levels
}

func (h *recordingHook) Fire(entry *logrus.Entry) error {
	h.callCount++
	if h.orderRef != nil {
		*h.orderRef = append(*h.orderRef, h.id)
	}
	if h.errToReturn != nil {
		return h.errToReturn
	}
	return nil
}

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

func runContractTests() error {
	// Assertion 1: LevelHooks.Add registers a hook for each log level specified by Hook.Levels
	{
		hooks := make(logrus.LevelHooks)
		hook := &recordingHook{
			levels: []logrus.Level{logrus.InfoLevel, logrus.ErrorLevel},
		}
		hooks.Add(hook)

		if len(hooks[logrus.InfoLevel]) != 1 || hooks[logrus.InfoLevel][0] != hook {
			return fmt.Errorf("assertion 1 failed: expected hook registered for InfoLevel")
		}
		if len(hooks[logrus.ErrorLevel]) != 1 || hooks[logrus.ErrorLevel][0] != hook {
			return fmt.Errorf("assertion 1 failed: expected hook registered for ErrorLevel")
		}
		if len(hooks[logrus.WarnLevel]) != 0 {
			return fmt.Errorf("assertion 1 failed: unexpected hook registered for WarnLevel")
		}
	}

	// Assertion 2: LevelHooks.Fire executes registered hooks for the specified log level
	{
		hooks := make(logrus.LevelHooks)
		hook := &recordingHook{
			levels: []logrus.Level{logrus.WarnLevel},
		}
		hooks.Add(hook)

		logger := logrus.New()
		logger.SetOutput(io.Discard)
		entry := logrus.NewEntry(logger)
		entry.Level = logrus.WarnLevel

		if err := hooks.Fire(logrus.WarnLevel, entry); err != nil {
			return fmt.Errorf("assertion 2 failed: unexpected error firing hook: %w", err)
		}
		if hook.callCount != 1 {
			return fmt.Errorf("assertion 2 failed: expected hook to fire once, fired %d times", hook.callCount)
		}
	}

	// Assertion 3: LevelHooks.Fire does not execute hooks registered for other log levels
	{
		hooks := make(logrus.LevelHooks)
		hook := &recordingHook{
			levels: []logrus.Level{logrus.ErrorLevel},
		}
		hooks.Add(hook)

		logger := logrus.New()
		logger.SetOutput(io.Discard)
		entry := logrus.NewEntry(logger)
		entry.Level = logrus.InfoLevel

		if err := hooks.Fire(logrus.InfoLevel, entry); err != nil {
			return fmt.Errorf("assertion 3 failed: unexpected error firing hook: %w", err)
		}
		if hook.callCount != 0 {
			return fmt.Errorf("assertion 3 failed: hook fired for non-matching level")
		}
	}

	// Assertion 4: LevelHooks.Fire returns the error returned by a hook and halts further hook execution
	{
		hooks := make(logrus.LevelHooks)
		expectedErr := errors.New("hook execution failure")
		hook1 := &recordingHook{
			levels:      []logrus.Level{logrus.DebugLevel},
			errToReturn: expectedErr,
		}
		hook2 := &recordingHook{
			levels: []logrus.Level{logrus.DebugLevel},
		}
		hooks.Add(hook1)
		hooks.Add(hook2)

		logger := logrus.New()
		logger.SetOutput(io.Discard)
		entry := logrus.NewEntry(logger)
		entry.Level = logrus.DebugLevel

		err := hooks.Fire(logrus.DebugLevel, entry)
		if err == nil {
			return fmt.Errorf("assertion 4 failed: expected error from Fire, got nil")
		}
		if !errors.Is(err, expectedErr) {
			return fmt.Errorf("assertion 4 failed: expected error %v, got %v", expectedErr, err)
		}
		if hook1.callCount != 1 {
			return fmt.Errorf("assertion 4 failed: expected hook1 to fire once, got %d", hook1.callCount)
		}
		if hook2.callCount != 0 {
			return fmt.Errorf("assertion 4 failed: expected hook2 not to fire after previous error, got %d", hook2.callCount)
		}
	}

	// Assertion 5: LevelHooks.Fire executes multiple hooks registered for the same level in insertion order
	{
		hooks := make(logrus.LevelHooks)
		var executionOrder []string

		hookA := &recordingHook{
			levels:   []logrus.Level{logrus.InfoLevel},
			id:       "first",
			orderRef: &executionOrder,
		}
		hookB := &recordingHook{
			levels:   []logrus.Level{logrus.InfoLevel},
			id:       "second",
			orderRef: &executionOrder,
		}
		hooks.Add(hookA)
		hooks.Add(hookB)

		logger := logrus.New()
		logger.SetOutput(io.Discard)
		entry := logrus.NewEntry(logger)
		entry.Level = logrus.InfoLevel

		if err := hooks.Fire(logrus.InfoLevel, entry); err != nil {
			return fmt.Errorf("assertion 5 failed: unexpected error firing hooks: %w", err)
		}
		if len(executionOrder) != 2 || executionOrder[0] != "first" || executionOrder[1] != "second" {
			return fmt.Errorf("assertion 5 failed: incorrect execution order: %v", executionOrder)
		}
	}

	return nil
}