218 lines
7.3 KiB
Go
218 lines
7.3 KiB
Go
![]() |
package aws
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import (
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"errors"
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"fmt"
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"log"
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"os"
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"strings"
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"time"
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"github.com/aws/aws-sdk-go/aws"
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"github.com/aws/aws-sdk-go/aws/awserr"
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awsCredentials "github.com/aws/aws-sdk-go/aws/credentials"
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"github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds"
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"github.com/aws/aws-sdk-go/aws/credentials/stscreds"
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"github.com/aws/aws-sdk-go/aws/ec2metadata"
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"github.com/aws/aws-sdk-go/aws/session"
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"github.com/aws/aws-sdk-go/service/iam"
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"github.com/aws/aws-sdk-go/service/sts"
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"github.com/hashicorp/errwrap"
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"github.com/hashicorp/go-cleanhttp"
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)
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func GetAccountInfo(iamconn *iam.IAM, stsconn *sts.STS, authProviderName string) (string, string, error) {
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// If we have creds from instance profile, we can use metadata API
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if authProviderName == ec2rolecreds.ProviderName {
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log.Println("[DEBUG] Trying to get account ID via AWS Metadata API")
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cfg := &aws.Config{}
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setOptionalEndpoint(cfg)
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sess, err := session.NewSession(cfg)
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if err != nil {
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return "", "", errwrap.Wrapf("Error creating AWS session: {{err}}", err)
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}
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metadataClient := ec2metadata.New(sess)
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info, err := metadataClient.IAMInfo()
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if err != nil {
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// This can be triggered when no IAM Role is assigned
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// or AWS just happens to return invalid response
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return "", "", fmt.Errorf("Failed getting EC2 IAM info: %s", err)
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}
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return parseAccountInfoFromArn(info.InstanceProfileArn)
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}
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// Then try IAM GetUser
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log.Println("[DEBUG] Trying to get account ID via iam:GetUser")
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outUser, err := iamconn.GetUser(nil)
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if err == nil {
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return parseAccountInfoFromArn(*outUser.User.Arn)
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}
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awsErr, ok := err.(awserr.Error)
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// AccessDenied and ValidationError can be raised
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// if credentials belong to federated profile, so we ignore these
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if !ok || (awsErr.Code() != "AccessDenied" && awsErr.Code() != "ValidationError" && awsErr.Code() != "InvalidClientTokenId") {
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return "", "", fmt.Errorf("Failed getting account ID via 'iam:GetUser': %s", err)
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}
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log.Printf("[DEBUG] Getting account ID via iam:GetUser failed: %s", err)
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// Then try STS GetCallerIdentity
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log.Println("[DEBUG] Trying to get account ID via sts:GetCallerIdentity")
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outCallerIdentity, err := stsconn.GetCallerIdentity(&sts.GetCallerIdentityInput{})
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if err == nil {
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return parseAccountInfoFromArn(*outCallerIdentity.Arn)
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}
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log.Printf("[DEBUG] Getting account ID via sts:GetCallerIdentity failed: %s", err)
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// Then try IAM ListRoles
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log.Println("[DEBUG] Trying to get account ID via iam:ListRoles")
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outRoles, err := iamconn.ListRoles(&iam.ListRolesInput{
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MaxItems: aws.Int64(int64(1)),
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})
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if err != nil {
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return "", "", fmt.Errorf("Failed getting account ID via 'iam:ListRoles': %s", err)
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}
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if len(outRoles.Roles) < 1 {
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return "", "", errors.New("Failed getting account ID via 'iam:ListRoles': No roles available")
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}
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return parseAccountInfoFromArn(*outRoles.Roles[0].Arn)
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}
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func parseAccountInfoFromArn(arn string) (string, string, error) {
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parts := strings.Split(arn, ":")
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if len(parts) < 5 {
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return "", "", fmt.Errorf("Unable to parse ID from invalid ARN: %q", arn)
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}
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return parts[1], parts[4], nil
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}
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// This function is responsible for reading credentials from the
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// environment in the case that they're not explicitly specified
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// in the Terraform configuration.
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func GetCredentials(c *Config) (*awsCredentials.Credentials, error) {
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// build a chain provider, lazy-evaulated by aws-sdk
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providers := []awsCredentials.Provider{
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&awsCredentials.StaticProvider{Value: awsCredentials.Value{
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AccessKeyID: c.AccessKey,
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SecretAccessKey: c.SecretKey,
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SessionToken: c.Token,
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}},
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&awsCredentials.EnvProvider{},
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&awsCredentials.SharedCredentialsProvider{
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Filename: c.CredsFilename,
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Profile: c.Profile,
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},
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}
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// Build isolated HTTP client to avoid issues with globally-shared settings
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client := cleanhttp.DefaultClient()
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// Keep the timeout low as we don't want to wait in non-EC2 environments
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client.Timeout = 100 * time.Millisecond
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cfg := &aws.Config{
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HTTPClient: client,
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}
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usedEndpoint := setOptionalEndpoint(cfg)
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if !c.SkipMetadataApiCheck {
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// Real AWS should reply to a simple metadata request.
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// We check it actually does to ensure something else didn't just
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// happen to be listening on the same IP:Port
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metadataClient := ec2metadata.New(session.New(cfg))
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if metadataClient.Available() {
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providers = append(providers, &ec2rolecreds.EC2RoleProvider{
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Client: metadataClient,
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})
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log.Print("[INFO] AWS EC2 instance detected via default metadata" +
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" API endpoint, EC2RoleProvider added to the auth chain")
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} else {
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if usedEndpoint == "" {
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usedEndpoint = "default location"
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}
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log.Printf("[INFO] Ignoring AWS metadata API endpoint at %s "+
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"as it doesn't return any instance-id", usedEndpoint)
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}
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}
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// This is the "normal" flow (i.e. not assuming a role)
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if c.AssumeRoleARN == "" {
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return awsCredentials.NewChainCredentials(providers), nil
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}
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// Otherwise we need to construct and STS client with the main credentials, and verify
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// that we can assume the defined role.
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log.Printf("[INFO] Attempting to AssumeRole %s (SessionName: %q, ExternalId: %q, Policy: %q)",
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c.AssumeRoleARN, c.AssumeRoleSessionName, c.AssumeRoleExternalID, c.AssumeRolePolicy)
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creds := awsCredentials.NewChainCredentials(providers)
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cp, err := creds.Get()
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if err != nil {
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if awsErr, ok := err.(awserr.Error); ok && awsErr.Code() == "NoCredentialProviders" {
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return nil, errors.New(`No valid credential sources found for AWS Provider.
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Please see https://terraform.io/docs/providers/aws/index.html for more information on
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providing credentials for the AWS Provider`)
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}
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return nil, fmt.Errorf("Error loading credentials for AWS Provider: %s", err)
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}
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log.Printf("[INFO] AWS Auth provider used: %q", cp.ProviderName)
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awsConfig := &aws.Config{
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Credentials: creds,
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Region: aws.String(c.Region),
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MaxRetries: aws.Int(c.MaxRetries),
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HTTPClient: cleanhttp.DefaultClient(),
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S3ForcePathStyle: aws.Bool(c.S3ForcePathStyle),
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}
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stsclient := sts.New(session.New(awsConfig))
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assumeRoleProvider := &stscreds.AssumeRoleProvider{
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Client: stsclient,
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RoleARN: c.AssumeRoleARN,
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}
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if c.AssumeRoleSessionName != "" {
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assumeRoleProvider.RoleSessionName = c.AssumeRoleSessionName
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}
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if c.AssumeRoleExternalID != "" {
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assumeRoleProvider.ExternalID = aws.String(c.AssumeRoleExternalID)
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}
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if c.AssumeRolePolicy != "" {
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assumeRoleProvider.Policy = aws.String(c.AssumeRolePolicy)
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}
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providers = []awsCredentials.Provider{assumeRoleProvider}
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assumeRoleCreds := awsCredentials.NewChainCredentials(providers)
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_, err = assumeRoleCreds.Get()
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if err != nil {
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if awsErr, ok := err.(awserr.Error); ok && awsErr.Code() == "NoCredentialProviders" {
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return nil, fmt.Errorf("The role %q cannot be assumed.\n\n"+
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" There are a number of possible causes of this - the most common are:\n"+
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" * The credentials used in order to assume the role are invalid\n"+
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" * The credentials do not have appropriate permission to assume the role\n"+
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" * The role ARN is not valid",
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c.AssumeRoleARN)
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}
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return nil, fmt.Errorf("Error loading credentials for AWS Provider: %s", err)
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}
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return assumeRoleCreds, nil
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}
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func setOptionalEndpoint(cfg *aws.Config) string {
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endpoint := os.Getenv("AWS_METADATA_URL")
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if endpoint != "" {
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log.Printf("[INFO] Setting custom metadata endpoint: %q", endpoint)
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cfg.Endpoint = aws.String(endpoint)
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return endpoint
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}
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return ""
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}
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