defaultsmode.go raw

   1  package config
   2  
   3  import (
   4  	"context"
   5  	"os"
   6  
   7  	"github.com/aws/aws-sdk-go-v2/aws"
   8  	"github.com/aws/aws-sdk-go-v2/feature/ec2/imds"
   9  )
  10  
  11  const execEnvVar = "AWS_EXECUTION_ENV"
  12  
  13  // DefaultsModeOptions is the set of options that are used to configure
  14  type DefaultsModeOptions struct {
  15  	// The SDK configuration defaults mode. Defaults to legacy if not specified.
  16  	//
  17  	// Supported modes are: auto, cross-region, in-region, legacy, mobile, standard
  18  	Mode aws.DefaultsMode
  19  
  20  	// The EC2 Instance Metadata Client that should be used when performing environment
  21  	// discovery when aws.DefaultsModeAuto is set.
  22  	//
  23  	// If not specified the SDK will construct a client if the instance metadata service has not been disabled by
  24  	// the AWS_EC2_METADATA_DISABLED environment variable.
  25  	IMDSClient *imds.Client
  26  }
  27  
  28  func resolveDefaultsModeRuntimeEnvironment(ctx context.Context, envConfig *EnvConfig, client *imds.Client) (aws.RuntimeEnvironment, error) {
  29  	getRegionOutput, err := client.GetRegion(ctx, &imds.GetRegionInput{})
  30  	// honor context timeouts, but if we couldn't talk to IMDS don't fail runtime environment introspection.
  31  	select {
  32  	case <-ctx.Done():
  33  		return aws.RuntimeEnvironment{}, err
  34  	default:
  35  	}
  36  
  37  	var imdsRegion string
  38  	if err == nil {
  39  		imdsRegion = getRegionOutput.Region
  40  	}
  41  
  42  	return aws.RuntimeEnvironment{
  43  		EnvironmentIdentifier:     aws.ExecutionEnvironmentID(os.Getenv(execEnvVar)),
  44  		Region:                    envConfig.Region,
  45  		EC2InstanceMetadataRegion: imdsRegion,
  46  	}, nil
  47  }
  48