Exit Manager

Exit Manager is a module for graceful shutdown coordination to ensure critical operations complete and cleanup runs before your application exits. See full documentation.

Features

• Signal handling: Listens for SIGINT (Ctrl+C) and SIGTERM
• Notifications: Notify() channel closes when shutdown starts
• Shutdown locks: Prevents exit until critical operations finish
• Cleanup functions: Runs cleanup in reverse registration order
• Context cancellation: Cancels contexts when shutdown begins

Installation

go get github.com/mcwalrus/exit-manager

Quick Start

1. Stop Goroutines on Shutdown

Listen for shutdown in your goroutines:

package main

import (
    "log"
    "time"
    exitmanager "github.com/mcwalrus/exit-manager"
)

func main() {
    em := exitmanager.Global()
    go worker(em)
    
    <-em.Notify()
    log.Println("Shutting down...")
    select {}
}

func worker(em *exitmanager.ExitManager) {
    ticker := time.NewTicker(time.Second)
    defer ticker.Stop()
    for {
        select {
        case <-em.Notify():
            log.Println("Worker stopping")
            return
        case <-ticker.C:
            log.Println("Working...")
        }
    }
}

2. Wait for Critical Operations

Use locks to ensure operations complete before shutdown:

package main

import (
    "log"
    "time"
    exitmanager "github.com/mcwalrus/exit-manager"
)

func main() {
    em := exitmanager.Global()
    go processData(em)
    
    log.Println("Running... Press Ctrl+C")
    <-em.Notify()

    log.Println("Waiting for operations to complete...")
    select {}
}

// performs critical operation
func processData(em *exitmanager.ExitManager) {
    // exit-manager will wait for process to complete
    _ = em.WithShutdownLock(func() error {
        time.Sleep(10 * time.Second)
        log.Println("Data processed")
    })
}

3. Clean Up Resources

Register cleanup functions that run automatically:

package main

import (
    "log"
    exitmanager "github.com/mcwalrus/exit-manager"
)

func main() {
    em := exitmanager.Global()
    
    em.RegisterCleanup(func() {
        log.Println("Closing database...")
    })
    em.RegisterCleanup(func() {
        log.Println("Closing cache...")
    })
    
    log.Println("Running... Press Ctrl+C")
    <-em.Notify()
    select {}
}

4. Context Cancellations

Use contexts that cancel on shutdown:

package main

import (
    "context"
    "log"
    "time"
    exitmanager "github.com/mcwalrus/exit-manager"
)

func main() {
    em := exitmanager.Global()
    ctx, cancel := em.NotifyContext(context.Background())
    defer cancel()
    
    go longTask(ctx)
    
    <-em.Notify()
    select {}
}

func longTask(ctx context.Context) {
    ticker := time.NewTicker(time.Second)
    defer ticker.Stop()
    for {
        select {
        case <-ctx.Done():
            log.Println("Task cancelled")
            return
        case <-ticker.C:
            log.Println("Processing...")
        }
    }
}

5. Timeout Configuration

Set a timeout to prevent shutdown from hanging:

package main

import (
    "log"
    "time"
    exitmanager "github.com/mcwalrus/exit-manager"
)

func main() {
    em := exitmanager.Global()
    em.SetTimeout(exitmanager.TimeoutModeGraceful, 10*time.Second)
    
    em.RegisterCleanup(func() {
        log.Println("Cleaning up...")
        time.Sleep(120 * time.Second) // timeout occurs first ...
    })
    
    log.Println("Running... Press Ctrl+C")
    <-em.Notify()
    select {}
}

6. Multiple Signals Handling

Configure how additional shutdown signals are handled:

package main

import (
    "log"
    "time"
    exitmanager "github.com/mcwalrus/exit-manager"
)

func main() {
    em := exitmanager.Global()
    em.SetMultipleSignals(exitmanager.MultipleSignalsModeForcefulExit)

    em.RegisterCleanup(func() {
        log.Println("Cleaning up...")
        time.Sleep(30 * time.Second)
    })
    
    log.Println("Running... Press Ctrl+C twice for immediate exit")
    <-em.Notify()
    select {}
}

Try the CLI Demo

See graceful shutdown in action:

cd cmd/exit-manager && go run .

Testing

go test -race ./...

Contributing

Report issues and feature requests at the GitHub repository.

License

This module is available under the MIT License.