sergerad_review_relax.go

package main

import (
	"context"
	"errors"
	"fmt"
	"github.com/sergerad/miscgo/pkg/relax"
	"golang.org/x/sync/errgroup"
)

func main() {
	//main1()
	main2()
}

func main2() {
	g, ctx := errgroup.WithContext(context.Background())
	fmt.Println("Hello World")
	defer fmt.Println("Goodbye World")

	// Do work, one will fail, all will finish
	g.Go(safeCall(func() error {
		return gone(ctx, "go1", false)
	}))
	g.Go(safeCall(func() error {
		return gone(ctx, "go2", false)
	}))
	g.Go(safeCall(func() error {
		return gone(ctx, "go3", true)
	}))

	// Wait for all
	if err := g.Wait(); err != nil {
		fmt.Println("failed successfully")
	}
}

func safeCall(fn func() error) func() error {
	return func() error {
		var err error
		defer func() {
			if r := recover(); r != nil {
				fmt.Println("recovered from panic:", r)
				err = errors.New(fmt.Sprintf("recovered from panic: %v", r))
			}

		}()

		err = fn()
		return err
	}
}

func gone(ctx context.Context, id string, fail bool) error {
	if fail {
		fmt.Printf("panicking: %s\n", id)
		panic("bad")
	}
	select {
	case <-ctx.Done():
		if ctx.Err() != nil {
			// ...
		}
	default:
	}
	fmt.Printf("shutting down: %s\n", id)
	return nil
}

func main1() {
	// Set up root context and error group
	g, ctx := relax.Main()

	fmt.Println("Hello World")
	defer fmt.Println("Goodbye World")

	// Do work, one will fail, all will finish
	g.Go(func() error {
		defer relax.Routine(ctx)
		return gone(ctx, "go1", false)
	})
	g.Go(func() error {
		defer relax.Routine(ctx)
		return gone(ctx, "go2", false)
	})
	g.Go(func() error {
		defer relax.Routine(ctx)
		return gone(ctx, "go3", true)
	})

	// Wait for all
	if err := g.Wait(); err != nil {
		fmt.Println("failed successfully")
	}
}