17215: add IAM role support to arvados-dispatch-cloud on EC2.

[arvados.git] / lib / cloud / ec2 / ec2.go

diff --git a/lib/cloud/ec2/ec2.go b/lib/cloud/ec2/ec2.go
index b20dbfcc986f764e78c51dead8a4ec11d427516a..1e0de74024f52851ebe4eb08c0414617d0bdc7db 100644 (file)
--- a/lib/cloud/ec2/ec2.go
+++ b/lib/cloud/ec2/ec2.go
@@ -19,6 +19,8 @@ import (
        "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/session"
        "github.com/aws/aws-sdk-go/service/ec2"
        "github.com/sirupsen/logrus"
@@ -65,12 +67,19 @@ 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 == "" {