cloudinit/datasource/metadata_service.go
Alex Crawford 361edeebc6 metadata-service: Add metadata-service datasource
Move the old metadata-service datasource to url datasource. This new datasource
checks for the existance of meta-data.json and if it doesn't exist, walks the
meta-data directory to build a metadata blob.
2014-06-24 15:08:03 -07:00

98 lines
2.2 KiB
Go

package datasource
import (
"bufio"
"bytes"
"encoding/json"
"strings"
"github.com/coreos/coreos-cloudinit/pkg"
)
type metadataService struct {
url string
}
type getter interface {
Get(string) ([]byte, error)
}
func NewMetadataService(url string) *metadataService {
return &metadataService{strings.TrimSuffix(url, "/")}
}
func (ms *metadataService) ConfigRoot() string {
return ""
}
func (ms *metadataService) FetchMetadata() ([]byte, error) {
client := pkg.NewHttpClient()
return fetchMetadata(client, ms.url)
}
func (ms *metadataService) FetchUserdata() ([]byte, error) {
client := pkg.NewHttpClient()
return client.Get(ms.url + "/latest/user-data")
}
func (ms *metadataService) Type() string {
return "metadata-service"
}
func fetchMetadata(client getter, url string) ([]byte, error) {
if metadata, err := client.Get(url + "/latest/meta-data.json"); err == nil {
return metadata, nil
} else if _, ok := err.(pkg.ErrTimeout); ok {
return nil, err
}
attrs, err := fetchChildAttributes(client, url+"/latest/meta-data/")
if err != nil {
return nil, err
}
return json.Marshal(attrs)
}
func fetchAttributes(client getter, url string) ([]string, error) {
resp, err := client.Get(url)
if err != nil {
return nil, err
}
scanner := bufio.NewScanner(bytes.NewBuffer(resp))
data := make([]string, 0)
for scanner.Scan() {
data = append(data, strings.Split(scanner.Text(), "=")[0])
}
return data, scanner.Err()
}
func fetchAttribute(client getter, url string) (interface{}, error) {
if attrs, err := fetchAttributes(client, url); err == nil {
return attrs[0], nil
} else {
return "", err
}
}
func fetchChildAttributes(client getter, url string) (interface{}, error) {
attrs := make(map[string]interface{})
attrList, err := fetchAttributes(client, url)
if err != nil {
return nil, err
}
for _, attr := range attrList {
var fetchFunc func(getter, string) (interface{}, error)
if strings.HasSuffix(attr, "/") {
fetchFunc = fetchChildAttributes
} else {
fetchFunc = fetchAttribute
}
if value, err := fetchFunc(client, url+attr); err == nil {
attrs[strings.TrimSuffix(attr, "/")] = value
} else {
return nil, err
}
}
return attrs, nil
}