multierrgroup

multierrgroup

multierrgroup combines sync.WaitGroup and hashicorp's multierror.Error to create a wait group that collects all reported errors.

Installation and Docs

Install using go get github.com/jribe/multierrgroup.

Full documentation is available at http://godoc.org/github.com/jribe/multierrgroup

Usage

multierrgroup is used just like sync.WaitGroup, except the Done method takes error as a parameter and the Wait method returns a multierror.Error or nil.

Doing work in separate goroutines

If all the calls to Done provide a nil error, Wait returns nil

package main

import (
    "github.com/jribe/multierrgroup"
    "log"
)

func main() {
    wg := &multierrgroup.WaitGroup{}

    wg.Add(2)
    go func() {
        log.Println("goroutine 1!")
        wg.Done(nil)
    }()
    go func() {
        log.Println("goroutine 2!")
        wg.Done(nil)
    }()

    if err := wg.Wait(); err != nil {
        log.Fatal(err)
    }
}

Counting random failures

Wait returns *multierror.Error instead of error, so you can directly access the list of errors.

package main

import (
    "fmt"
    "github.com/jribe/multierrgroup"
    "log"
    "math/rand"
)

func RandomlyFail(i int) error {
    number := rand.New(rand.NewSource(int64(i))).Intn(2)
    if number != 0 {
        return fmt.Errorf("%d failed", number)
    }
    return nil
}

func main() {
    wg := &multierrgroup.WaitGroup{}

    for i := 0; i < 300; i++ {
        wg.Add(1)
        go func(i int) {
            err := RandomlyFail(i)
            wg.Done(err)
        }(i)
    }

    err := wg.Wait()
    log.Printf("there were %d errors!", len(err.Errors))
    log.Print(err)
}