Use AWS SDK EC2 metadata client.

pkg/cloudprovider/providers/aws/aws.go

@@ -20,7 +20,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/url"
@@ -34,6 +33,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/aws/credentials"
 	"github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds"
+	"github.com/aws/aws-sdk-go/aws/ec2metadata"
 	"github.com/aws/aws-sdk-go/service/autoscaling"
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/aws/aws-sdk-go/service/elb"
@@ -61,7 +61,7 @@ type AWSServices interface {
 	Compute(region string) (EC2, error)
 	LoadBalancing(region string) (ELB, error)
 	Autoscaling(region string) (ASG, error)
-	Metadata() AWSMetadata
+	Metadata() (EC2Metadata, error)
 }
 
 // TODO: Should we rename this to AWS (EBS & ELB are not technically part of EC2)
@@ -129,9 +129,9 @@ type ASG interface {
 }
 
 // Abstraction over the AWS metadata service
-type AWSMetadata interface {
+type EC2Metadata interface {
 	// Query the EC2 metadata service (used to discover instance-id etc)
-	GetMetaData(key string) ([]byte, error)
+	GetMetadata(path string) (string, error)
 }
 
 type VolumeOptions struct {
@@ -175,6 +175,7 @@ type AWSCloud struct {
 	ec2              EC2
 	elb              ELB
 	asg              ASG
+	metadata         EC2Metadata
 	cfg              *AWSCloudConfig
 	availabilityZone string
 	region           string
@@ -232,8 +233,9 @@ func (p *awsSDKProvider) Autoscaling(regionName string) (ASG, error) {
 	return client, nil
 }
 
-func (p *awsSDKProvider) Metadata() AWSMetadata {
-	return &awsSdkMetadata{}
+func (p *awsSDKProvider) Metadata() (EC2Metadata, error) {
+	client := ec2metadata.New(nil)
+	return client, nil
 }
 
 func stringPointerArray(orig []string) []*string {
@@ -307,34 +309,16 @@ func (self *awsSdkEC2) DescribeInstances(request *ec2.DescribeInstancesInput) ([
 }
 
 type awsSdkMetadata struct {
+	metadata *ec2metadata.Client
 }
 
 var metadataClient = http.Client{
 	Timeout: time.Second * 10,
 }
 
-// Implements AWSMetadata.GetMetaData
-func (self *awsSdkMetadata) GetMetaData(key string) ([]byte, error) {
-	// TODO Get an implementation of this merged into aws-sdk-go
-	url := "http://169.254.169.254/latest/meta-data/" + key
-
-	res, err := metadataClient.Get(url)
-	if err != nil {
-		return nil, err
-	}
-	defer res.Body.Close()
-
-	if res.StatusCode != 200 {
-		err = fmt.Errorf("Code %d returned for url %s", res.StatusCode, url)
-		return nil, fmt.Errorf("Error querying AWS metadata for key %s: %v", key, err)
-	}
-
-	body, err := ioutil.ReadAll(res.Body)
-	if err != nil {
-		return nil, fmt.Errorf("Error querying AWS metadata for key %s: %v", key, err)
-	}
-
-	return []byte(body), nil
+// Implements EC2Metadata.GetMetadata
+func (self *awsSdkMetadata) GetMetadata(path string) (string, error) {
+	return self.metadata.GetMetadata(path)
 }
 
 // Implements EC2.DescribeSecurityGroups
@@ -466,7 +450,7 @@ func init() {
 }
 
 // readAWSCloudConfig reads an instance of AWSCloudConfig from config reader.
-func readAWSCloudConfig(config io.Reader, metadata AWSMetadata) (*AWSCloudConfig, error) {
+func readAWSCloudConfig(config io.Reader, metadata EC2Metadata) (*AWSCloudConfig, error) {
 	var cfg AWSCloudConfig
 	var err error
 
@@ -493,15 +477,8 @@ func readAWSCloudConfig(config io.Reader, metadata AWSMetadata) (*AWSCloudConfig
 	return &cfg, nil
 }
 
-func getAvailabilityZone(metadata AWSMetadata) (string, error) {
-	availabilityZoneBytes, err := metadata.GetMetaData("placement/availability-zone")
-	if err != nil {
-		return "", err
-	}
-	if availabilityZoneBytes == nil || len(availabilityZoneBytes) == 0 {
-		return "", fmt.Errorf("Unable to determine availability-zone from instance metadata")
-	}
-	return string(availabilityZoneBytes), nil
+func getAvailabilityZone(metadata EC2Metadata) (string, error) {
+	return metadata.GetMetadata("placement/availability-zone")
 }
 
 func isRegionValid(region string) bool {
@@ -527,7 +504,11 @@ func isRegionValid(region string) bool {
 // newAWSCloud creates a new instance of AWSCloud.
 // AWSProvider and instanceId are primarily for tests
 func newAWSCloud(config io.Reader, awsServices AWSServices) (*AWSCloud, error) {
-	metadata := awsServices.Metadata()
+	metadata, err := awsServices.Metadata()
+	if err != nil {
+		return nil, fmt.Errorf("error creating AWS metadata client: %v", err)
+	}
+
 	cfg, err := readAWSCloudConfig(config, metadata)
 	if err != nil {
 		return nil, fmt.Errorf("unable to read AWS cloud provider config file: %v", err)
@@ -564,6 +545,7 @@ func newAWSCloud(config io.Reader, awsServices AWSServices) (*AWSCloud, error) {
 		ec2:              ec2,
 		elb:              elb,
 		asg:              asg,
+		metadata:         metadata,
 		cfg:              cfg,
 		region:           regionName,
 		availabilityZone: zone,
@@ -1059,17 +1041,16 @@ func (s *AWSCloud) getSelfAWSInstance() (*awsInstance, error) {
 
 	i := s.selfAWSInstance
 	if i == nil {
-		metadata := s.awsServices.Metadata()
-		instanceIdBytes, err := metadata.GetMetaData("instance-id")
+		instanceId, err := s.metadata.GetMetadata("instance-id")
 		if err != nil {
 			return nil, fmt.Errorf("error fetching instance-id from ec2 metadata service: %v", err)
 		}
-		privateDnsNameBytes, err := metadata.GetMetaData("local-hostname")
+		privateDnsName, err := s.metadata.GetMetadata("local-hostname")
 		if err != nil {
 			return nil, fmt.Errorf("error fetching local-hostname from ec2 metadata service: %v", err)
 		}
 
-		i = newAWSInstance(s.ec2, string(instanceIdBytes), string(privateDnsNameBytes))
+		i = newAWSInstance(s.ec2, instanceId, privateDnsName)
 		s.selfAWSInstance = i
 	}
 
@@ -1254,27 +1235,24 @@ func (s *AWSCloud) describeLoadBalancer(name string) (*elb.LoadBalancerDescripti
 
 // Retrieves instance's vpc id from metadata
 func (self *AWSCloud) findVPCID() (string, error) {
-
-	metadata := self.awsServices.Metadata()
-	macsBytes, err := metadata.GetMetaData("network/interfaces/macs/")
+	macs, err := self.metadata.GetMetadata("network/interfaces/macs/")
 	if err != nil {
 		return "", fmt.Errorf("Could not list interfaces of the instance", err)
 	}
 
 	// loop over interfaces, first vpc id returned wins
-	for _, macPath := range strings.Split(string(macsBytes), "\n") {
-
+	for _, macPath := range strings.Split(macs, "\n") {
 		if len(macPath) == 0 {
 			continue
 		}
 		url := fmt.Sprintf("network/interfaces/macs/%svpc-id", macPath)
-		vpcIDBytes, err := metadata.GetMetaData(url)
+		vpcID, err := self.metadata.GetMetadata(url)
 		if err != nil {
 			continue
 		}
-		return string(vpcIDBytes), nil
+		return vpcID, nil
 	}
-	return "", fmt.Errorf("Could not find VPC id in instance metadata")
+	return "", fmt.Errorf("Could not find VPC ID in instance metadata")
 }
 
 // Find the VPC which self is attached to.

pkg/cloudprovider/providers/aws/aws_test.go

@@ -83,9 +83,9 @@ func TestReadAWSCloudConfig(t *testing.T) {
 
 	for _, test := range tests {
 		t.Logf("Running test case %s", test.name)
-		var metadata AWSMetadata
+		var metadata EC2Metadata
 		if test.aws != nil {
-			metadata = test.aws.Metadata()
+			metadata, _ = test.aws.Metadata()
 		}
 		cfg, err := readAWSCloudConfig(test.reader, metadata)
 		if test.expectError {
@@ -166,8 +166,8 @@ func (s *FakeAWSServices) Autoscaling(region string) (ASG, error) {
 	return s.asg, nil
 }
 
-func (s *FakeAWSServices) Metadata() AWSMetadata {
-	return s.metadata
+func (s *FakeAWSServices) Metadata() (EC2Metadata, error) {
+	return s.metadata, nil
 }
 
 func TestFilterTags(t *testing.T) {
@@ -313,31 +313,31 @@ type FakeMetadata struct {
 	aws *FakeAWSServices
 }
 
-func (self *FakeMetadata) GetMetaData(key string) ([]byte, error) {
+func (self *FakeMetadata) GetMetadata(key string) (string, error) {
 	networkInterfacesPrefix := "network/interfaces/macs/"
 	if key == "placement/availability-zone" {
-		return []byte(self.aws.availabilityZone), nil
+		return self.aws.availabilityZone, nil
 	} else if key == "instance-id" {
-		return []byte(self.aws.instanceId), nil
+		return self.aws.instanceId, nil
 	} else if key == "local-hostname" {
-		return []byte(self.aws.privateDnsName), nil
+		return self.aws.privateDnsName, nil
 	} else if strings.HasPrefix(key, networkInterfacesPrefix) {
 		if key == networkInterfacesPrefix {
-			return []byte(strings.Join(self.aws.networkInterfacesMacs, "/\n") + "/\n"), nil
+			return strings.Join(self.aws.networkInterfacesMacs, "/\n") + "/\n", nil
 		} else {
 			keySplit := strings.Split(key, "/")
 			macParam := keySplit[3]
 			if len(keySplit) == 5 && keySplit[4] == "vpc-id" {
 				for i, macElem := range self.aws.networkInterfacesMacs {
 					if macParam == macElem {
-						return []byte(self.aws.networkInterfacesVpcIDs[i]), nil
+						return self.aws.networkInterfacesVpcIDs[i], nil
 					}
 				}
 			}
-			return nil, nil
+			return "", nil
 		}
 	} else {
-		return nil, nil
+		return "", nil
 	}
 }