cloudinit/datasource/waagent/waagent.go

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package waagent
import (
"encoding/json"
"encoding/xml"
"fmt"
"io/ioutil"
"net"
"os"
"path"
)
type waagent struct {
root string
readFile func(filename string) ([]byte, error)
}
func NewDatasource(root string) *waagent {
return &waagent{root, ioutil.ReadFile}
}
func (a *waagent) IsAvailable() bool {
_, err := os.Stat(path.Join(a.root, "provisioned"))
return !os.IsNotExist(err)
}
func (a *waagent) AvailabilityChanges() bool {
return true
}
func (a *waagent) ConfigRoot() string {
return a.root
}
func (a *waagent) FetchMetadata() ([]byte, error) {
metadataBytes, err := a.tryReadFile(path.Join(a.root, "SharedConfig.xml"))
if err != nil {
return nil, err
}
if len(metadataBytes) == 0 {
return metadataBytes, nil
}
type Instance struct {
Id string `xml:"id,attr"`
Address string `xml:"address,attr"`
InputEndpoints struct {
Endpoints []struct {
LoadBalancedPublicAddress string `xml:"loadBalancedPublicAddress,attr"`
} `xml:"Endpoint"`
}
}
type SharedConfig struct {
Incarnation struct {
Instance string `xml:"instance,attr"`
}
Instances struct {
Instances []Instance `xml:"Instance"`
}
}
var metadata SharedConfig
if err := xml.Unmarshal(metadataBytes, &metadata); err != nil {
return nil, err
}
var instance Instance
for _, i := range metadata.Instances.Instances {
if i.Id == metadata.Incarnation.Instance {
instance = i
break
}
}
attrs := map[string]string{
"local-ipv4": instance.Address,
}
for _, e := range instance.InputEndpoints.Endpoints {
host, _, err := net.SplitHostPort(e.LoadBalancedPublicAddress)
if err == nil {
attrs["public-ipv4"] = host
break
}
}
return json.Marshal(attrs)
}
func (a *waagent) FetchUserdata() ([]byte, error) {
return a.tryReadFile(path.Join(a.root, "CustomData"))
}
func (a *waagent) FetchNetworkConfig(filename string) ([]byte, error) {
return nil, nil
}
func (a *waagent) Type() string {
return "waagent"
}
func (a *waagent) tryReadFile(filename string) ([]byte, error) {
fmt.Printf("Attempting to read from %q\n", filename)
data, err := a.readFile(filename)
if os.IsNotExist(err) {
err = nil
}
return data, err
}