How to catch errors from Goroutines? - go

Question

I've created function which needs to run in goroutine, the code is working(this is just simple sample to illustrate the issue)
go rze(ftFilePath, 2)
func rze(ftDataPath,duration time.Duration) error {
}
I want to do something like this
errs := make(chan error, 1)
err := go rze(ftFilePath, 2)
if err != nil{
r <- Result{result, errs}
}
but not sure how to it, most of the examples show
how you do it when you using func
https://tour.golang.org/concurrency/5

Answer 1

You cannot use the return value of a function that is executed with the go keyword. Use an anonymous function instead:
errs := make(chan error, 1)
go func() {
errs <- rze(ftFilePath, 2)
}()
// later:
if err := <-errs; err != nil {
// handle error
}

Answer 2

You can use golang errgroup pkg.
var eg errgroup.Group
eg.Go(func() error {
return rze(ftFilePath, 2)
})
if err := g.Wait(); err != nil {
r <- Result{result, errs}
}

Answer 3

You can handle error from go routines using a separate channel for errors. Create a separate channel specifically for errors. Each child go routine must pass corresponding errors into this channel.
This is one of the ways how it can be done:
func main() {
type err error
items := []string{"1", "2", "3"}
ch := make(chan err, len(items))
for _, f := range items {
go func(f string) {
var e err
e = testFunc(f)
ch <- e
}(f)
}
for range items {
e := <-ch
fmt.Println("Error: ", e)
if e != nil {
// DO Something
}
}
}
func testFunc(item string) error {
if item == "1" {
return errors.New("err")
}
return nil
}