X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/ffe94bef9cd17abb522d7fabb32326405d466a94..ff11506c916cb2cd8abd1905e16c4d4f5ddd4240:/lib/cloud/ec2/ec2.go

diff --git a/lib/cloud/ec2/ec2.go b/lib/cloud/ec2/ec2.go
index c329c1f88a..b7afdf0ecd 100644
--- a/lib/cloud/ec2/ec2.go
+++ b/lib/cloud/ec2/ec2.go
@@ -14,11 +14,16 @@ import (
 	"fmt"
 	"math/big"
 	"sync"
+	"sync/atomic"
+	"time"
 
 	"git.arvados.org/arvados.git/lib/cloud"
 	"git.arvados.org/arvados.git/sdk/go/arvados"
 	"github.com/aws/aws-sdk-go/aws"
 	"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/aws/request"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/sirupsen/logrus"
@@ -28,6 +33,11 @@ import (
 // Driver is the ec2 implementation of the cloud.Driver interface.
 var Driver = cloud.DriverFunc(newEC2InstanceSet)
 
+const (
+	throttleDelayMin = time.Second
+	throttleDelayMax = time.Minute
+)
+
 type ec2InstanceSetConfig struct {
 	AccessKeyID      string
 	SecretAccessKey  string
@@ -54,6 +64,7 @@ type ec2InstanceSet struct {
 	client        ec2Interface
 	keysMtx       sync.Mutex
 	keys          map[string]string
+	throttleDelay atomic.Value
 }
 
 func newEC2InstanceSet(config json.RawMessage, instanceSetID cloud.InstanceSetID, _ cloud.SharedResourceTags, logger logrus.FieldLogger) (prv cloud.InstanceSet, err error) {
@@ -65,12 +76,19 @@ func newEC2InstanceSet(config json.RawMessage, instanceSetID cloud.InstanceSetID
 	if err != nil {
 		return nil, err
 	}
-	awsConfig := aws.NewConfig().
-		WithCredentials(credentials.NewStaticCredentials(
-			instanceSet.ec2config.AccessKeyID,
-			instanceSet.ec2config.SecretAccessKey,
-			"")).
-		WithRegion(instanceSet.ec2config.Region)
+
+	sess, err := session.NewSession()
+	if err != nil {
+		return nil, err
+	}
+	// First try any static credentials, fall back to an IAM instance profile/role
+	creds := credentials.NewChainCredentials(
+		[]credentials.Provider{
+			&credentials.StaticProvider{Value: credentials.Value{AccessKeyID: instanceSet.ec2config.AccessKeyID, SecretAccessKey: instanceSet.ec2config.SecretAccessKey}},
+			&ec2rolecreds.EC2RoleProvider{Client: ec2metadata.New(sess)},
+		})
+
+	awsConfig := aws.NewConfig().WithCredentials(creds).WithRegion(instanceSet.ec2config.Region)
 	instanceSet.client = ec2.New(session.Must(session.NewSession(awsConfig)))
 	instanceSet.keys = make(map[string]string)
 	if instanceSet.ec2config.EBSVolumeType == "" {
@@ -103,10 +121,10 @@ func awsKeyFingerprint(pk ssh.PublicKey) (md5fp string, sha1fp string, err error
 	sha1pkix := sha1.Sum([]byte(pkix))
 	md5fp = ""
 	sha1fp = ""
-	for i := 0; i < len(md5pkix); i += 1 {
+	for i := 0; i < len(md5pkix); i++ {
 		md5fp += fmt.Sprintf(":%02x", md5pkix[i])
 	}
-	for i := 0; i < len(sha1pkix); i += 1 {
+	for i := 0; i < len(sha1pkix); i++ {
 		sha1fp += fmt.Sprintf(":%02x", sha1pkix[i])
 	}
 	return md5fp[1:], sha1fp[1:], nil
@@ -212,8 +230,23 @@ func (instanceSet *ec2InstanceSet) Create(
 
 	rsv, err := instanceSet.client.RunInstances(&rii)
 
-	if err != nil {
+	if request.IsErrorThrottle(err) {
+		// Back off exponentially until a create call either
+		// succeeds or returns a non-throttle error.
+		d, _ := instanceSet.throttleDelay.Load().(time.Duration)
+		d = d*3/2 + time.Second
+		if d < throttleDelayMin {
+			d = throttleDelayMin
+		} else if d > throttleDelayMax {
+			d = throttleDelayMax
+		}
+		instanceSet.throttleDelay.Store(d)
+		return nil, rateLimitError{error: err, earliestRetry: time.Now().Add(d)}
+	} else if err != nil {
+		instanceSet.throttleDelay.Store(time.Duration(0))
 		return nil, err
+	} else {
+		instanceSet.throttleDelay.Store(time.Duration(0))
 	}
 
 	return &ec2Instance{
@@ -251,7 +284,7 @@ func (instanceSet *ec2InstanceSet) Instances(tags cloud.InstanceTags) (instances
 	}
 }
 
-func (az *ec2InstanceSet) Stop() {
+func (instanceSet *ec2InstanceSet) Stop() {
 }
 
 type ec2Instance struct {
@@ -308,9 +341,8 @@ func (inst *ec2Instance) Destroy() error {
 func (inst *ec2Instance) Address() string {
 	if inst.instance.PrivateIpAddress != nil {
 		return *inst.instance.PrivateIpAddress
-	} else {
-		return ""
 	}
+	return ""
 }
 
 func (inst *ec2Instance) RemoteUser() string {
@@ -320,3 +352,12 @@ func (inst *ec2Instance) RemoteUser() string {
 func (inst *ec2Instance) VerifyHostKey(ssh.PublicKey, *ssh.Client) error {
 	return cloud.ErrNotImplemented
 }
+
+type rateLimitError struct {
+	error
+	earliestRetry time.Time
+}
+
+func (err rateLimitError) EarliestRetry() time.Time {
+	return err.earliestRetry
+}