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

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package common
import (
"errors"
"fmt"
"log"
"net"
"os"
"strconv"
"strings"
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"time"
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"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/service/ec2"
"github.com/mitchellh/multistep"
)
// 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.DescribeImages(&ec2.DescribeImagesInput{
ImageIds: []*string{&imageId},
})
if err != nil {
if ec2err, ok := err.(awserr.Error); ok && ec2err.Code() == "InvalidAMIID.NotFound" {
// Set this to nil as if we didn't find anything.
resp = nil
} else if isTransientNetworkError(err) {
// Transient network error, treat it 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, instanceId string) StateRefreshFunc {
return func() (interface{}, string, error) {
resp, err := conn.DescribeInstances(&ec2.DescribeInstancesInput{
InstanceIds: []*string{&instanceId},
})
if err != nil {
if ec2err, ok := err.(awserr.Error); ok && ec2err.Code() == "InvalidInstanceID.NotFound" {
// Set this to nil as if we didn't find anything.
resp = nil
} else if isTransientNetworkError(err) {
// Transient network error, treat it 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
}
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i := resp.Reservations[0].Instances[0]
return i, *i.State.Name, nil
}
}
// SpotRequestStateRefreshFunc returns a StateRefreshFunc that is used to watch
// a spot request for state changes.
func SpotRequestStateRefreshFunc(conn *ec2.EC2, spotRequestId string) StateRefreshFunc {
return func() (interface{}, string, error) {
resp, err := conn.DescribeSpotInstanceRequests(&ec2.DescribeSpotInstanceRequestsInput{
SpotInstanceRequestIds: []*string{&spotRequestId},
})
if err != nil {
if ec2err, ok := err.(awserr.Error); ok && ec2err.Code() == "InvalidSpotInstanceRequestID.NotFound" {
// Set this to nil as if we didn't find anything.
resp = nil
} else if isTransientNetworkError(err) {
// Transient network error, treat it as if we didn't find anything
resp = nil
} else {
log.Printf("Error on SpotRequestStateRefresh: %s", err)
return nil, "", err
}
}
if resp == nil || len(resp.SpotInstanceRequests) == 0 {
// Sometimes AWS has consistency issues and doesn't see the
// SpotRequest. Return an empty state.
return nil, "", nil
}
i := resp.SpotInstanceRequests[0]
return i, *i.State, nil
}
}
func ImportImageRefreshFunc(conn *ec2.EC2, importTaskId string) StateRefreshFunc {
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return func() (interface{}, string, error) {
resp, err := conn.DescribeImportImageTasks(&ec2.DescribeImportImageTasksInput{
ImportTaskIds: []*string{
&importTaskId,
},
},
)
if err != nil {
if ec2err, ok := err.(awserr.Error); ok && strings.HasPrefix(ec2err.Code(), "InvalidConversionTaskId") {
resp = nil
} else if isTransientNetworkError(err) {
resp = nil
} else {
log.Printf("Error on ImportImageRefresh: %s", err)
return nil, "", err
}
}
if resp == nil || len(resp.ImportImageTasks) == 0 {
return nil, "", nil
}
i := resp.ImportImageTasks[0]
return i, *i.Status, 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)
sleepSeconds := SleepSeconds()
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maxTicks := int(TimeoutSeconds()/sleepSeconds) + 1
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 > maxTicks {
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 {
err := fmt.Errorf("unexpected state '%s', wanted target '%s'", currentState, conf.Target)
return nil, err
}
}
time.Sleep(time.Duration(sleepSeconds) * time.Second)
}
}
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func isTransientNetworkError(err error) bool {
if nerr, ok := err.(net.Error); ok && nerr.Temporary() {
return true
}
return false
}
// Returns 300 seconds (5 minutes) by default
// Some AWS operations, like copying an AMI to a distant region, take a very long time
// Allow user to override with AWS_TIMEOUT_SECONDS environment variable
func TimeoutSeconds() (seconds int) {
seconds = 300
override := os.Getenv("AWS_TIMEOUT_SECONDS")
if override != "" {
n, err := strconv.Atoi(override)
if err != nil {
log.Printf("Invalid timeout seconds '%s', using default", override)
} else {
seconds = n
}
}
log.Printf("Allowing %ds to complete (change with AWS_TIMEOUT_SECONDS)", seconds)
return seconds
}
// Returns 2 seconds by default
// AWS async operations sometimes takes long times, if there are multiple parallel builds,
// polling at 2 second frequency will exceed the request limit. Allow 2 seconds to be
// overwritten with AWS_POLL_DELAY_SECONDS
func SleepSeconds() (seconds int) {
seconds = 2
override := os.Getenv("AWS_POLL_DELAY_SECONDS")
if override != "" {
n, err := strconv.Atoi(override)
if err != nil {
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log.Printf("Invalid sleep seconds '%s', using default", override)
} else {
seconds = n
}
}
log.Printf("Using %ds as polling delay (change with AWS_POLL_DELAY_SECONDS)", seconds)
return seconds
}