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package aws
import (
"context"
"net/http"
"strings"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/ec2metadata"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/hairyhenderson/gomplate/v4/env"
"github.com/hairyhenderson/gomplate/v4/internal/deprecated"
)
const (
// the default region
unknown = "unknown"
)
// Ec2Meta -
type Ec2Meta struct {
metadataCache map[string]string
dynamicdataCache map[string]string
ec2MetadataProvider func() (EC2Metadata, error)
nonAWS bool
}
type EC2Metadata interface {
GetMetadata(p string) (string, error)
GetDynamicData(p string) (string, error)
Region() (string, error)
}
// NewEc2Meta -
func NewEc2Meta(options ClientOptions) *Ec2Meta {
return &Ec2Meta{
metadataCache: make(map[string]string),
dynamicdataCache: make(map[string]string),
ec2MetadataProvider: func() (EC2Metadata, error) {
config := aws.NewConfig()
config = config.WithHTTPClient(&http.Client{Timeout: options.Timeout})
if endpoint := env.Getenv("AWS_META_ENDPOINT"); endpoint != "" {
deprecated.WarnDeprecated(context.Background(), "Use AWS_EC2_METADATA_SERVICE_ENDPOINT instead of AWS_META_ENDPOINT")
config = config.WithEndpoint(endpoint)
}
s, err := session.NewSession(config)
if err != nil {
return nil, err
}
return ec2metadata.New(s), nil
},
}
}
// returnDefault -
func returnDefault(def []string) string {
if len(def) > 0 {
return def[0]
}
return ""
}
func unreachable(err error) bool {
if strings.Contains(err.Error(), "request canceled") ||
strings.Contains(err.Error(), "no route to host") ||
strings.Contains(err.Error(), "host is down") {
return true
}
return false
}
func (e *Ec2Meta) retrieveMetadata(key string, def ...string) (string, error) {
if value, ok := e.metadataCache[key]; ok {
return value, nil
}
if e.nonAWS {
return returnDefault(def), nil
}
emd, err := e.ec2MetadataProvider()
if err != nil {
return "", err
}
value, err := emd.GetMetadata(key)
if err != nil {
if unreachable(err) {
e.nonAWS = true
}
return returnDefault(def), nil
}
e.metadataCache[key] = value
return value, nil
}
func (e *Ec2Meta) retrieveDynamicdata(key string, def ...string) (string, error) {
if value, ok := e.dynamicdataCache[key]; ok {
return value, nil
}
if e.nonAWS {
return returnDefault(def), nil
}
emd, err := e.ec2MetadataProvider()
if err != nil {
return "", err
}
value, err := emd.GetDynamicData(key)
if err != nil {
if unreachable(err) {
e.nonAWS = true
}
return returnDefault(def), nil
}
e.dynamicdataCache[key] = value
return value, nil
}
// Meta -
func (e *Ec2Meta) Meta(key string, def ...string) (string, error) {
return e.retrieveMetadata(key, def...)
}
// Dynamic -
func (e *Ec2Meta) Dynamic(key string, def ...string) (string, error) {
return e.retrieveDynamicdata(key, def...)
}
// Region -
func (e *Ec2Meta) Region(def ...string) (string, error) {
defaultRegion := returnDefault(def)
if defaultRegion == "" {
defaultRegion = unknown
}
if e.nonAWS {
return defaultRegion, nil
}
emd, err := e.ec2MetadataProvider()
if err != nil {
return "", err
}
region, err := emd.Region()
if err != nil || region == "" {
return defaultRegion, nil
}
return region, nil
}
|
