resolvers.go

Documentation: github.com/aws/aws-sdk-go-v2/feature/ec2/imds/internal/config

     1  package config
     2  
     3  import (
     4  	"fmt"
     5  	"strings"
     6  )
     7  
     8  // ClientEnableState provides an enumeration if the client is enabled,
     9  // disabled, or default behavior.
    10  type ClientEnableState uint
    11  
    12  // Enumeration values for ClientEnableState
    13  const (
    14  	ClientDefaultEnableState ClientEnableState = iota
    15  	ClientDisabled
    16  	ClientEnabled
    17  )
    18  
    19  // EndpointModeState is the EC2 IMDS Endpoint Configuration Mode
    20  type EndpointModeState uint
    21  
    22  // Enumeration values for ClientEnableState
    23  const (
    24  	EndpointModeStateUnset EndpointModeState = iota
    25  	EndpointModeStateIPv4
    26  	EndpointModeStateIPv6
    27  )
    28  
    29  // SetFromString sets the EndpointModeState based on the provided string value. Unknown values will default to EndpointModeStateUnset
    30  func (e *EndpointModeState) SetFromString(v string) error {
    31  	v = strings.TrimSpace(v)
    32  
    33  	switch {
    34  	case len(v) == 0:
    35  		*e = EndpointModeStateUnset
    36  	case strings.EqualFold(v, "IPv6"):
    37  		*e = EndpointModeStateIPv6
    38  	case strings.EqualFold(v, "IPv4"):
    39  		*e = EndpointModeStateIPv4
    40  	default:
    41  		return fmt.Errorf("unknown EC2 IMDS endpoint mode, must be either IPv6 or IPv4")
    42  	}
    43  	return nil
    44  }
    45  
    46  // ClientEnableStateResolver is a config resolver interface for retrieving whether the IMDS client is disabled.
    47  type ClientEnableStateResolver interface {
    48  	GetEC2IMDSClientEnableState() (ClientEnableState, bool, error)
    49  }
    50  
    51  // EndpointModeResolver is a config resolver interface for retrieving the EndpointModeState configuration.
    52  type EndpointModeResolver interface {
    53  	GetEC2IMDSEndpointMode() (EndpointModeState, bool, error)
    54  }
    55  
    56  // EndpointResolver is a config resolver interface for retrieving the endpoint.
    57  type EndpointResolver interface {
    58  	GetEC2IMDSEndpoint() (string, bool, error)
    59  }
    60  
    61  type v1FallbackDisabledResolver interface {
    62  	GetEC2IMDSV1FallbackDisabled() (bool, bool)
    63  }
    64  
    65  // ResolveClientEnableState resolves the ClientEnableState from a list of configuration sources.
    66  func ResolveClientEnableState(sources []interface{}) (value ClientEnableState, found bool, err error) {
    67  	for _, source := range sources {
    68  		if resolver, ok := source.(ClientEnableStateResolver); ok {
    69  			value, found, err = resolver.GetEC2IMDSClientEnableState()
    70  			if err != nil || found {
    71  				return value, found, err
    72  			}
    73  		}
    74  	}
    75  	return value, found, err
    76  }
    77  
    78  // ResolveEndpointModeConfig resolves the EndpointModeState from a list of configuration sources.
    79  func ResolveEndpointModeConfig(sources []interface{}) (value EndpointModeState, found bool, err error) {
    80  	for _, source := range sources {
    81  		if resolver, ok := source.(EndpointModeResolver); ok {
    82  			value, found, err = resolver.GetEC2IMDSEndpointMode()
    83  			if err != nil || found {
    84  				return value, found, err
    85  			}
    86  		}
    87  	}
    88  	return value, found, err
    89  }
    90  
    91  // ResolveEndpointConfig resolves the endpoint from a list of configuration sources.
    92  func ResolveEndpointConfig(sources []interface{}) (value string, found bool, err error) {
    93  	for _, source := range sources {
    94  		if resolver, ok := source.(EndpointResolver); ok {
    95  			value, found, err = resolver.GetEC2IMDSEndpoint()
    96  			if err != nil || found {
    97  				return value, found, err
    98  			}
    99  		}
   100  	}
   101  	return value, found, err
   102  }
   103  
   104  // ResolveV1FallbackDisabled ...
   105  func ResolveV1FallbackDisabled(sources []interface{}) (bool, bool) {
   106  	for _, source := range sources {
   107  		if resolver, ok := source.(v1FallbackDisabledResolver); ok {
   108  			if v, found := resolver.GetEC2IMDSV1FallbackDisabled(); found {
   109  				return v, true
   110  			}
   111  		}
   112  	}
   113  	return false, false
   114  }
   115
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