Documentation
¶
Overview ¶
Package gxerrgroup implements an actor-runner with deterministic teardown. It is somewhat similar to package errgroup, except it does not require actor goroutines to understand context semantics. This makes it suitable for use in more circumstances; for example, goroutines which are handling connections from net.Listeners, or scanning input from a closable io.Reader.
refers to github.com/oklog/run
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Group ¶
type Group struct {
// contains filtered or unexported fields
}
Group collects actors (functions) and runs them concurrently. When one actor (function) returns, all actors are interrupted. The zero value of a Group is useful.
func NewGroup ¶
NewGroup initialize a Group instance which will create a goroutine pool. idleTimeout is a goroutine's max idle time interval.
func (*Group) Add ¶
Add an actor (function) to the group. Each actor must be pre-emptable by an interrupt function. That is, if interrupt is invoked, execute should return. Also, it must be safe to call interrupt even after execute has returned.
The first actor (function) to return interrupts all running actors. The error is passed to the interrupt functions, and is returned by Run.
Example (Basic) ¶
var g *Group
g = NewGroup(10e9)
defer g.Close()
{
cancel := make(chan struct{})
g.Add(func() error {
select {
case <-time.After(time.Second):
fmt.Printf("The first actor had its time elapsed\n")
return nil
case <-cancel:
fmt.Printf("The first actor was canceled\n")
return nil
}
}, func(err error) {
fmt.Printf("The first actor was interrupted with: %v\n", err)
close(cancel)
})
}
{
g.Add(func() error {
fmt.Printf("The second actor is returning immediately\n")
return errors.New("immediate teardown")
}, func(err error) {
// Note that this interrupt function is called, even though the
// corresponding execute function has already returned.
fmt.Printf("The second actor was interrupted with: %v\n", err)
})
}
fmt.Printf("The group was terminated with: %v\n", g.Run())
Output: The second actor is returning immediately The first actor was interrupted with: immediate teardown The second actor was interrupted with: immediate teardown The first actor was canceled The group was terminated with: immediate teardown
Example (Context) ¶
var g *Group
ctx, cancel := context.WithCancel(context.Background())
g = NewGroup(10e9)
defer g.Close()
{
ctx, cancel := context.WithCancel(ctx) // note: shadowed
g.Add(func() error {
return runUntilCanceled(ctx)
}, func(error) {
cancel()
})
}
go cancel()
fmt.Printf("The group was terminated with: %v\n", g.Run())
Output: The group was terminated with: context canceled
Example (Listener) ¶
var g *Group
g = NewGroup(10e9)
defer g.Close()
{
ln, _ := net.Listen("tcp", ":0")
g.Add(func() error {
defer fmt.Printf("http.Serve returned\n")
return http.Serve(ln, http.NewServeMux())
}, func(error) {
ln.Close()
})
}
{
g.Add(func() error {
return errors.New("immediate teardown")
}, func(error) {
//
})
}
fmt.Printf("The group was terminated with: %v\n", g.Run())
Output: http.Serve returned The group was terminated with: immediate teardown
Source Files