Merge pull request #8560 from hashicorp/jbardin/race2

Fix races in WaitForState
This commit is contained in:
James Bardin 2016-08-31 14:02:43 -04:00 committed by GitHub
commit e0014198e1
1 changed files with 52 additions and 38 deletions

View File

@ -2,6 +2,7 @@ package resource
import (
"log"
"sync/atomic"
"time"
)
@ -61,9 +62,15 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
conf.ContinuousTargetOccurence = 1
}
var result interface{}
var resulterr error
var currentState string
// We can't safely read the result values if we timeout, so store them in
// an atomic.Value
type Result struct {
Result interface{}
State string
Error error
}
var lastResult atomic.Value
lastResult.Store(Result{})
doneCh := make(chan struct{})
go func() {
@ -74,39 +81,21 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
wait := 100 * time.Millisecond
var err error
for first := true; ; first = false {
if !first {
// If a poll interval has been specified, choose that interval.
// Otherwise bound the default value.
if conf.PollInterval > 0 && conf.PollInterval < 180*time.Second {
wait = conf.PollInterval
} else {
if wait < conf.MinTimeout {
wait = conf.MinTimeout
} else if wait > 10*time.Second {
wait = 10 * time.Second
}
}
log.Printf("[TRACE] Waiting %s before next try", wait)
time.Sleep(wait)
// Wait between refreshes using exponential backoff, except when
// waiting for the target state to reoccur.
if targetOccurence == 0 {
wait *= 2
}
for {
res, currentState, err := conf.Refresh()
result := Result{
Result: res,
State: currentState,
Error: err,
}
lastResult.Store(result)
result, currentState, err = conf.Refresh()
if err != nil {
resulterr = err
return
}
// If we're waiting for the absence of a thing, then return
if result == nil && len(conf.Target) == 0 {
if res == nil && len(conf.Target) == 0 {
targetOccurence += 1
if conf.ContinuousTargetOccurence == targetOccurence {
return
@ -115,14 +104,15 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
}
}
if result == nil {
if res == nil {
// If we didn't find the resource, check if we have been
// not finding it for awhile, and if so, report an error.
notfoundTick += 1
if notfoundTick > conf.NotFoundChecks {
resulterr = &NotFoundError{
LastError: resulterr,
result.Error = &NotFoundError{
LastError: err,
}
lastResult.Store(result)
return
}
} else {
@ -151,24 +141,48 @@ func (conf *StateChangeConf) WaitForState() (interface{}, error) {
}
if !found {
resulterr = &UnexpectedStateError{
LastError: resulterr,
State: currentState,
result.Error = &UnexpectedStateError{
LastError: err,
State: result.State,
ExpectedState: conf.Target,
}
lastResult.Store(result)
return
}
}
// If a poll interval has been specified, choose that interval.
// Otherwise bound the default value.
if conf.PollInterval > 0 && conf.PollInterval < 180*time.Second {
wait = conf.PollInterval
} else {
if wait < conf.MinTimeout {
wait = conf.MinTimeout
} else if wait > 10*time.Second {
wait = 10 * time.Second
}
}
log.Printf("[TRACE] Waiting %s before next try", wait)
time.Sleep(wait)
// Wait between refreshes using exponential backoff, except when
// waiting for the target state to reoccur.
if targetOccurence == 0 {
wait *= 2
}
}
}()
select {
case <-doneCh:
return result, resulterr
r := lastResult.Load().(Result)
return r.Result, r.Error
case <-time.After(conf.Timeout):
r := lastResult.Load().(Result)
return nil, &TimeoutError{
LastError: resulterr,
LastState: currentState,
LastError: r.Error,
LastState: r.State,
ExpectedState: conf.Target,
}
}