packer-cn/builder/amazon/common/state.go

138 lines
3.7 KiB
Go

package common
import (
"errors"
"fmt"
"github.com/mitchellh/goamz/ec2"
"github.com/mitchellh/multistep"
"log"
"time"
)
// StateRefreshFunc is a function type used for StateChangeConf that is
// responsible for refreshing the item being watched for a state change.
//
// It returns three results. `result` is any object that will be returned
// as the final object after waiting for state change. This allows you to
// return the final updated object, for example an EC2 instance after refreshing
// it.
//
// `state` is the latest state of that object. And `err` is any error that
// may have happened while refreshing the state.
type StateRefreshFunc func() (result interface{}, state string, err error)
// StateChangeConf is the configuration struct used for `WaitForState`.
type StateChangeConf struct {
Pending []string
Refresh StateRefreshFunc
StepState multistep.StateBag
Target string
}
// AMIStateRefreshFunc returns a StateRefreshFunc that is used to watch
// an AMI for state changes.
func AMIStateRefreshFunc(conn *ec2.EC2, imageId string) StateRefreshFunc {
return func() (interface{}, string, error) {
resp, err := conn.Images([]string{imageId}, ec2.NewFilter())
if err != nil {
if ec2err, ok := err.(*ec2.Error); ok && ec2err.Code == "InvalidAMIID.NotFound" {
// Set this to nil as if we didn't find anything.
resp = nil
} else {
log.Printf("Error on AMIStateRefresh: %s", err)
return nil, "", err
}
}
if resp == nil || len(resp.Images) == 0 {
// Sometimes AWS has consistency issues and doesn't see the
// AMI. Return an empty state.
return nil, "", nil
}
i := resp.Images[0]
return i, i.State, nil
}
}
// InstanceStateRefreshFunc returns a StateRefreshFunc that is used to watch
// an EC2 instance.
func InstanceStateRefreshFunc(conn *ec2.EC2, i *ec2.Instance) StateRefreshFunc {
return func() (interface{}, string, error) {
resp, err := conn.Instances([]string{i.InstanceId}, ec2.NewFilter())
if err != nil {
if ec2err, ok := err.(*ec2.Error); ok && ec2err.Code == "InvalidInstanceID.NotFound" {
// Set this to nil as if we didn't find anything.
resp = nil
} else {
log.Printf("Error on InstanceStateRefresh: %s", err)
return nil, "", err
}
}
if resp == nil || len(resp.Reservations) == 0 || len(resp.Reservations[0].Instances) == 0 {
// Sometimes AWS just has consistency issues and doesn't see
// our instance yet. Return an empty state.
return nil, "", nil
}
i = &resp.Reservations[0].Instances[0]
return i, i.State.Name, nil
}
}
// WaitForState watches an object and waits for it to achieve a certain
// state.
func WaitForState(conf *StateChangeConf) (i interface{}, err error) {
log.Printf("Waiting for state to become: %s", conf.Target)
notfoundTick := 0
for {
var currentState string
i, currentState, err = conf.Refresh()
if err != nil {
return
}
if i == 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 > 20 {
return nil, errors.New("couldn't find resource")
}
} else {
// Reset the counter for when a resource isn't found
notfoundTick = 0
if currentState == conf.Target {
return
}
if conf.StepState != nil {
if _, ok := conf.StepState.GetOk(multistep.StateCancelled); ok {
return nil, errors.New("interrupted")
}
}
found := false
for _, allowed := range conf.Pending {
if currentState == allowed {
found = true
break
}
}
if !found {
fmt.Errorf("unexpected state '%s', wanted target '%s'", currentState, conf.Target)
return
}
}
time.Sleep(2 * time.Second)
}
return
}