traefik/vendor/github.com/sacloud/libsacloud/api/polling.go

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2018-07-03 10:44:04 +00:00
package api
import (
"fmt"
"time"
)
type pollingHandler func() (exit bool, state interface{}, err error)
func poll(handler pollingHandler, timeout time.Duration) (chan (interface{}), chan (interface{}), chan (error)) {
compChan := make(chan interface{})
progChan := make(chan interface{})
errChan := make(chan error)
tick := time.Tick(5 * time.Second)
bomb := time.After(timeout)
go func() {
for {
select {
case <-tick:
exit, state, err := handler()
if err != nil {
errChan <- fmt.Errorf("Failed: poll: %s", err)
return
}
if state != nil {
progChan <- state
if exit {
compChan <- state
return
}
}
case <-bomb:
errChan <- fmt.Errorf("Timeout")
return
}
}
}()
return compChan, progChan, errChan
}
func blockingPoll(handler pollingHandler, timeout time.Duration) error {
c, p, e := poll(handler, timeout)
for {
select {
case <-c:
return nil
case <-p:
// noop
case err := <-e:
return err
}
}
}
type hasAvailable interface {
IsAvailable() bool
}
type hasFailed interface {
IsFailed() bool
}
func waitingForAvailableFunc(readFunc func() (hasAvailable, error), maxRetry int) func() (bool, interface{}, error) {
counter := 0
return func() (bool, interface{}, error) {
counter++
v, err := readFunc()
if err != nil {
if maxRetry > 0 && counter < maxRetry {
return false, nil, nil
}
return false, nil, err
}
if v == nil {
return false, nil, fmt.Errorf("readFunc returns nil")
}
if v.IsAvailable() {
return true, v, nil
}
if f, ok := v.(hasFailed); ok && f.IsFailed() {
return false, v, fmt.Errorf("InstanceState is failed: %#v", v)
}
return false, v, nil
}
}
type hasUpDown interface {
IsUp() bool
IsDown() bool
}
func waitingForUpFunc(readFunc func() (hasUpDown, error), maxRetry int) func() (bool, interface{}, error) {
counter := 0
return func() (bool, interface{}, error) {
counter++
v, err := readFunc()
if err != nil {
if maxRetry > 0 && counter < maxRetry {
return false, nil, nil
}
return false, nil, err
}
if v == nil {
return false, nil, fmt.Errorf("readFunc returns nil")
}
if v.IsUp() {
return true, v, nil
}
return false, v, nil
}
}
func waitingForDownFunc(readFunc func() (hasUpDown, error), maxRetry int) func() (bool, interface{}, error) {
counter := 0
return func() (bool, interface{}, error) {
counter++
v, err := readFunc()
if err != nil {
if maxRetry > 0 && counter < maxRetry {
return false, nil, nil
}
return false, nil, err
}
if v == nil {
return false, nil, fmt.Errorf("readFunc returns nil")
}
if v.IsDown() {
return true, v, nil
}
return false, v, nil
}
}
func waitingForReadFunc(readFunc func() (interface{}, error), maxRetry int) func() (bool, interface{}, error) {
counter := 0
return func() (bool, interface{}, error) {
counter++
v, err := readFunc()
if err != nil {
if maxRetry > 0 && counter < maxRetry {
return false, nil, nil
}
return false, nil, err
}
if v != nil {
return true, v, nil
}
return false, v, nil
}
}