105 lines
2.7 KiB
Go
105 lines
2.7 KiB
Go
package datasource
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import (
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"bufio"
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"bytes"
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"encoding/json"
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"strings"
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"github.com/coreos/coreos-cloudinit/pkg"
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)
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// metadataService retrieves metadata from either an OpenStack[1] or EC2[2] compatible endpoint.
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// It will first attempt to directly retrieve a JSON blob from the OpenStack endpoint. If that
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// fails with a 404, it then attempts to retrieve metadata bit-by-bit from the EC2 endpoint,
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// and populates that into an equivalent JSON blob.
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//
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// [1] http://docs.openstack.org/grizzly/openstack-compute/admin/content/metadata-service.html
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// [2] http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AESDG-chapter-instancedata.html#instancedata-data-categories
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type metadataService struct {
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url string
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}
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type getter interface {
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Get(string) ([]byte, error)
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}
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func NewMetadataService(url string) *metadataService {
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return &metadataService{strings.TrimSuffix(url, "/")}
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}
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func (ms *metadataService) ConfigRoot() string {
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return ""
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}
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func (ms *metadataService) FetchMetadata() ([]byte, error) {
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client := pkg.NewHttpClient()
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return fetchMetadata(client, ms.url)
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}
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func (ms *metadataService) FetchUserdata() ([]byte, error) {
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client := pkg.NewHttpClient()
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return client.Get(ms.url + "/latest/user-data")
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}
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func (ms *metadataService) Type() string {
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return "metadata-service"
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}
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func fetchMetadata(client getter, url string) ([]byte, error) {
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if metadata, err := client.Get(url + "/latest/meta-data.json"); err == nil {
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return metadata, nil
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} else if _, ok := err.(pkg.ErrTimeout); ok {
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return nil, err
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}
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attrs, err := fetchChildAttributes(client, url+"/latest/meta-data/")
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if err != nil {
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return nil, err
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}
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return json.Marshal(attrs)
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}
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func fetchAttributes(client getter, url string) ([]string, error) {
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resp, err := client.Get(url)
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if err != nil {
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return nil, err
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}
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scanner := bufio.NewScanner(bytes.NewBuffer(resp))
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data := make([]string, 0)
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for scanner.Scan() {
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data = append(data, strings.Split(scanner.Text(), "=")[0])
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}
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return data, scanner.Err()
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}
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func fetchAttribute(client getter, url string) (interface{}, error) {
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if attrs, err := fetchAttributes(client, url); err == nil {
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return attrs[0], nil
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} else {
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return "", err
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}
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}
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func fetchChildAttributes(client getter, url string) (interface{}, error) {
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attrs := make(map[string]interface{})
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attrList, err := fetchAttributes(client, url)
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if err != nil {
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return nil, err
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}
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for _, attr := range attrList {
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var fetchFunc func(getter, string) (interface{}, error)
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if strings.HasSuffix(attr, "/") {
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fetchFunc = fetchChildAttributes
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} else {
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fetchFunc = fetchAttribute
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}
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if value, err := fetchFunc(client, url+attr); err == nil {
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attrs[strings.TrimSuffix(attr, "/")] = value
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} else {
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return nil, err
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}
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}
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return attrs, nil
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}
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