builder/amazon: parallelize AMI region copies [GH-495]

CHANGELOG.md

@@ -20,6 +20,8 @@ IMPROVEMENTS:
 * core: Plugins communicate over a single TCP connection per plugin now,
   instead of sometimes dozens. Performance around plugin communication
   dramatically increased.
+* builder/amazon/all: Copying AMIs to multiple regions now happens
+  in parallel. [GH-495]
 * provisioner/puppet-masterless: Can now specify a `manifest_dir` to
   upload manifests to the remote machine for imports. [GH-655]
 

builder/amazon/common/step_ami_region_copy.go

@@ -6,6 +6,7 @@ import (
 	"github.com/mitchellh/goamz/ec2"
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
+	"sync"
 )
 
 type StepAMIRegionCopy struct {
@@ -23,41 +24,37 @@ func (s *StepAMIRegionCopy) Run(state multistep.StateBag) multistep.StepAction {
 	}
 
 	ui.Say(fmt.Sprintf("Copying AMI (%s) to other regions...", ami))
+
+	var lock sync.Mutex
+	var wg sync.WaitGroup
+	errs := new(packer.MultiError)
 	for _, region := range s.Regions {
+		wg.Add(1)
 		ui.Message(fmt.Sprintf("Copying to: %s", region))
 
-		// Connect to the region where the AMI will be copied to
-		regionconn := ec2.New(ec2conn.Auth, aws.Regions[region])
-		resp, err := regionconn.CopyImage(&ec2.CopyImage{
-			SourceRegion:  ec2conn.Region.Name,
-			SourceImageId: ami,
-		})
+		go func(region string) {
+			defer wg.Done()
+			id, err := amiRegionCopy(state, ec2conn.Auth, ami,
+				aws.Regions[region], ec2conn.Region)
 
-		if err != nil {
-			err := fmt.Errorf("Error Copying AMI (%s) to region (%s): %s", ami, region, err)
-			state.Put("error", err)
-			ui.Error(err.Error())
-			return multistep.ActionHalt
-		}
+			lock.Lock()
+			defer lock.Unlock()
+			amis[region] = id
+			if err != nil {
+				errs = packer.MultiErrorAppend(errs, err)
+			}
+		}(region)
+	}
 
-		stateChange := StateChangeConf{
-			Conn:      regionconn,
-			Pending:   []string{"pending"},
-			Target:    "available",
-			Refresh:   AMIStateRefreshFunc(regionconn, resp.ImageId),
-			StepState: state,
-		}
+	// TODO(mitchellh): Wait but also allow for cancels to go through...
+	ui.Message("Waiting for all copies to complete...")
+	wg.Wait()
 
-		ui.Say(fmt.Sprintf("Waiting for AMI (%s) in region (%s) to become ready...",
-			resp.ImageId, region))
-		if _, err := WaitForState(&stateChange); err != nil {
-			err := fmt.Errorf("Error waiting for AMI (%s) in region (%s): %s", resp.ImageId, region, err)
-			state.Put("error", err)
-			ui.Error(err.Error())
-			return multistep.ActionHalt
-		}
-
-		amis[region] = resp.ImageId
+	// If there were errors, show them
+	if len(errs.Errors) > 0 {
+		state.Put("error", errs)
+		ui.Error(errs.Error())
+		return multistep.ActionHalt
 	}
 
 	state.Put("amis", amis)
@@ -67,3 +64,36 @@ func (s *StepAMIRegionCopy) Run(state multistep.StateBag) multistep.StepAction {
 func (s *StepAMIRegionCopy) Cleanup(state multistep.StateBag) {
 	// No cleanup...
 }
+
+// amiRegionCopy does a copy for the given AMI to the target region and
+// returns the resulting ID or error.
+func amiRegionCopy(state multistep.StateBag, auth aws.Auth, imageId string,
+	target aws.Region, source aws.Region) (string, error) {
+
+	// Connect to the region where the AMI will be copied to
+	regionconn := ec2.New(auth, target)
+	resp, err := regionconn.CopyImage(&ec2.CopyImage{
+		SourceRegion:  source.Name,
+		SourceImageId: imageId,
+	})
+
+	if err != nil {
+		return "", fmt.Errorf("Error Copying AMI (%s) to region (%s): %s",
+			imageId, target, err)
+	}
+
+	stateChange := StateChangeConf{
+		Conn:      regionconn,
+		Pending:   []string{"pending"},
+		Target:    "available",
+		Refresh:   AMIStateRefreshFunc(regionconn, resp.ImageId),
+		StepState: state,
+	}
+
+	if _, err := WaitForState(&stateChange); err != nil {
+		return "", fmt.Errorf("Error waiting for AMI (%s) in region (%s): %s",
+			resp.ImageId, target, err)
+	}
+
+	return resp.ImageId, nil
+}

test/builder_amazon_ebs.bats

@@ -7,11 +7,30 @@
 load test_helper
 fixtures amazon-ebs
 
+# This counts how many AMIs were copied to another region
+aws_ami_region_copy_count() {
+    aws ec2 describe-images --region $1 --owners self --output text \
+        --filters 'Name=tag:packer-id,Values=ami_region_copy' \
+        --query "Images[*].ImageId" \
+        | wc -l
+}
+
 teardown() {
-    aws_ami_cleanup
+    aws_ami_cleanup 'us-east-1'
+    aws_ami_cleanup 'us-west-1'
+    aws_ami_cleanup 'us-west-2'
 }
 
 @test "amazon-ebs: build minimal.json" {
     run packer build $FIXTURE_ROOT/minimal.json
     [ "$status" -eq 0 ]
 }
+
+# @unit-testable
+@test "amazon-ebs: AMI region copy" {
+    run packer build $FIXTURE_ROOT/ami_region_copy.json
+    [ "$status" -eq 0 ]
+    [ "$(aws_ami_region_copy_count 'us-east-1')" -eq "1" ]
+    [ "$(aws_ami_region_copy_count 'us-west-1')" -eq "1" ]
+    [ "$(aws_ami_region_copy_count 'us-west-2')" -eq "1" ]
+}

test/fixtures/amazon-ebs/ami_region_copy.json

@@ -0,0 +1,15 @@
+{
+    "builders": [{
+        "type": "amazon-ebs",
+        "ami_name": "packer-test {{timestamp}}",
+        "instance_type": "m1.small",
+        "region": "us-east-1",
+        "ssh_username": "ubuntu",
+        "source_ami": "ami-0568456c",
+        "tags": {
+            "packer-test": "true",
+            "packer-id": "ami_region_copy"
+        },
+        "ami_regions": ["us-west-1", "us-west-2"]
+    }]
+}

test/test_helper.bash

@@ -39,7 +39,9 @@ fixtures() {
 
 # This deletes any AMIs with a tag "packer-test" of "true"
 aws_ami_cleanup() {
-    aws ec2 describe-images --owners self --output json --filters 'Name=tag:packer-test,Values=true' \
+    local region=${1:-us-east-1}
+    aws ec2 describe-images --region ${region} --owners self --output json \
+        --filters 'Name=tag:packer-test,Values=true' \
         | jq -r -M '.Images[]["ImageId"]' \
-        | xargs -n1 aws ec2 deregister-image --image-id
+        | xargs -n1 aws ec2 deregister-image --region ${region} --image-id
 }