Files
linuxkit/pkg/metadata/provider_gcp.go
Rolf Neugebauer 105cb48ad6 metadata: Simplify the GCP SSH code
Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
2017-04-12 16:19:24 +01:00

123 lines
3.1 KiB
Go

package main
import (
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
"path"
"strings"
"time"
)
const (
project = "http://metadata.google.internal/computeMetadata/v1/project/"
instance = "http://metadata.google.internal/computeMetadata/v1/instance/"
)
// ProviderGCP is the type implementing the Provider interface for GCP
type ProviderGCP struct {
}
// NewGCP returns a new ProviderGCP
func NewGCP() *ProviderGCP {
return &ProviderGCP{}
}
func (p *ProviderGCP) String() string {
return "GCP"
}
// Probe checks if we are running on GCP
func (p *ProviderGCP) Probe() bool {
// Getting the hostname should always work...
_, err := gcpGet(instance + "hostname")
return (err == nil)
}
// Extract gets both the GCP specific and generic userdata
func (p *ProviderGCP) Extract() ([]byte, error) {
// Get host name. This must not fail
hostname, err := gcpGet(instance + "hostname")
if err != nil {
return nil, err
}
err = ioutil.WriteFile(path.Join(ConfigPath, Hostname), hostname, 0644)
if err != nil {
return nil, fmt.Errorf("GCP: Failed to write hostname: %s", err)
}
if err := p.handleSSH(); err != nil {
log.Printf("GCP: Failed to get ssh data: %s", err)
}
// Generic userdata
userData, err := gcpGet(instance + "attributes/userdata")
if err != nil {
log.Printf("GCP: Failed to get user-data: %s", err)
// This is not an error
return nil, nil
}
return userData, nil
}
// gcpGet requests and extracts the requested URL
func gcpGet(url string) ([]byte, error) {
var client = &http.Client{
Timeout: time.Second * 2,
}
req, err := http.NewRequest("", url, nil)
if err != nil {
return nil, fmt.Errorf("GCP: http.NewRequest failed: %s", err)
}
req.Header.Set("Metadata-Flavor", "Google")
resp, err := client.Do(req)
if err != nil {
return nil, fmt.Errorf("GCP: Could not contact metadata service: %s", err)
}
if resp.StatusCode != 200 {
return nil, fmt.Errorf("GCP: Status not ok: %d", resp.StatusCode)
}
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("GCP: Failed to read http response: %s", err)
}
return body, nil
}
// SSH keys:
// TODO also retrieve the instance keys and respect block
// project keys see:
// https://cloud.google.com/compute/docs/instances/ssh-keys
// The keys have usernames attached, but as a simplification
// we are going to add them all to one root file
// TODO split them into individual user files and make the ssh
// container construct those users
func (p *ProviderGCP) handleSSH() error {
sshKeys, err := gcpGet(project + "attributes/sshKeys")
if err != nil {
return fmt.Errorf("Failed to get sshKeys: %s", err)
}
if err := os.Mkdir(path.Join(ConfigPath, SSH), 0755); err != nil {
return fmt.Errorf("Failed to create %s: %s", SSH, err)
}
rootKeys := ""
for _, line := range strings.Split(string(sshKeys), "\n") {
parts := strings.SplitN(line, ":", 2)
// ignoring username for now
if len(parts) == 2 {
rootKeys = rootKeys + parts[1] + "\n"
}
}
err = ioutil.WriteFile(path.Join(ConfigPath, SSH, "authorized_keys"), []byte(rootKeys), 0600)
if err != nil {
return fmt.Errorf("Failed to write ssh keys: %s", err)
}
return nil
}