linuxkit/pkg/metadata/provider_aws.go
David Gageot 39807bb0bd Remove dead or redundant code
Signed-off-by: David Gageot <david.gageot@docker.com>
2022-10-09 15:33:42 +02:00

135 lines
3.4 KiB
Go

package main
import (
"fmt"
"io"
"log"
"net/http"
"os"
"path"
"time"
)
// ProviderAWS is the type implementing the Provider interface for AWS
type ProviderAWS struct {
}
// NewAWS returns a new ProviderAWS
func NewAWS() *ProviderAWS {
return &ProviderAWS{}
}
func (p *ProviderAWS) String() string {
return "AWS"
}
// Probe checks if we are running on AWS
func (p *ProviderAWS) Probe() bool {
// Getting the hostname should always work...
_, err := awsGet(metaDataURL + "hostname")
return err == nil
}
// Extract gets both the AWS specific and generic userdata
func (p *ProviderAWS) Extract() ([]byte, error) {
// Get host name. This must not fail
hostname, err := awsGet(metaDataURL + "hostname")
if err != nil {
return nil, err
}
err = os.WriteFile(path.Join(ConfigPath, Hostname), hostname, 0644)
if err != nil {
return nil, fmt.Errorf("AWS: Failed to write hostname: %s", err)
}
// public ipv4
awsMetaGet("public-ipv4", "public_ipv4", 0644)
// private ipv4
awsMetaGet("local-ipv4", "local_ipv4", 0644)
// availability zone
awsMetaGet("placement/availability-zone", "availability_zone", 0644)
// instance type
awsMetaGet("instance-type", "instance_type", 0644)
// instance-id
awsMetaGet("instance-id", "instance_id", 0644)
// local-hostname
awsMetaGet("local-hostname", "local_hostname", 0644)
// ssh
if err := p.handleSSH(); err != nil {
log.Printf("AWS: Failed to get ssh data: %s", err)
}
// Generic userdata
userData, err := awsGet(userDataURL)
if err != nil {
log.Printf("AWS: Failed to get user-data: %s", err)
// This is not an error
return nil, nil
}
return userData, nil
}
// lookup a value (lookupName) in aws metaservice and store in given fileName
func awsMetaGet(lookupName string, fileName string, fileMode os.FileMode) {
if lookupValue, err := awsGet(metaDataURL + lookupName); err == nil {
// we got a value from the metadata server, now save to filesystem
err = os.WriteFile(path.Join(ConfigPath, fileName), lookupValue, fileMode)
if err != nil {
// we couldn't save the file for some reason
log.Printf("AWS: Failed to write %s:%s %s", fileName, lookupValue, err)
}
} else {
// we did not get a value back from the metadata server
log.Printf("AWS: Failed to get %s: %s", lookupName, err)
}
}
// awsGet requests and extracts the requested URL
func awsGet(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("AWS: http.NewRequest failed: %s", err)
}
resp, err := client.Do(req)
if err != nil {
return nil, fmt.Errorf("AWS: Could not contact metadata service: %s", err)
}
if resp.StatusCode != 200 {
return nil, fmt.Errorf("AWS: Status not ok: %d", resp.StatusCode)
}
body, err := io.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("AWS: Failed to read http response: %s", err)
}
return body, nil
}
// SSH keys:
func (p *ProviderAWS) handleSSH() error {
sshKeys, err := awsGet(metaDataURL + "public-keys/0/openssh-key")
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)
}
err = os.WriteFile(path.Join(ConfigPath, SSH, "authorized_keys"), sshKeys, 0600)
if err != nil {
return fmt.Errorf("Failed to write ssh keys: %s", err)
}
return nil
}