cloudinit/datasource/proc_cmdline.go

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package datasource
import (
"errors"
"io/ioutil"
"log"
"strings"
"github.com/coreos/coreos-cloudinit/pkg"
)
const (
ProcCmdlineLocation = "/proc/cmdline"
ProcCmdlineCloudConfigFlag = "cloud-config-url"
)
type procCmdline struct {
Location string
}
func NewProcCmdline() *procCmdline {
return &procCmdline{Location: ProcCmdlineLocation}
}
func (c *procCmdline) ConfigRoot() string {
return ""
}
func (c *procCmdline) FetchMetadata() ([]byte, error) {
return []byte{}, nil
}
func (c *procCmdline) FetchUserdata() ([]byte, error) {
contents, err := ioutil.ReadFile(c.Location)
if err != nil {
return nil, err
}
cmdline := strings.TrimSpace(string(contents))
url, err := findCloudConfigURL(cmdline)
if err != nil {
return nil, err
}
client := pkg.NewHttpClient()
cfg, err := client.GetRetry(url)
if err != nil {
return nil, err
}
return cfg, nil
}
func (c *procCmdline) Type() string {
return "proc-cmdline"
}
func findCloudConfigURL(input string) (url string, err error) {
err = errors.New("cloud-config-url not found")
for _, token := range strings.Split(input, " ") {
parts := strings.SplitN(token, "=", 2)
key := parts[0]
key = strings.Replace(key, "_", "-", -1)
if key != "cloud-config-url" {
continue
}
if len(parts) != 2 {
log.Printf("Found cloud-config-url in /proc/cmdline with no value, ignoring.")
continue
}
url = parts[1]
err = nil
}
return
}