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// Package raw wraps SSH commands necessary for K8s inspection.
package raw
import (
"bytes"
"errors"
"io/ioutil"
"os/user"
"path/filepath"
"golang.org/x/crypto/ssh"
kh "golang.org/x/crypto/ssh/knownhosts"
"check/config"
)
const (
controlplane = "controlplane"
etcd = "etcd"
worker = "worker"
k8sProcess = "kube-apiserver"
dockerInspectCmd = "docker inspect " + k8sProcess + " --format {{.Args}}"
knownHostsFile = "~/.ssh/known_hosts"
)
// GetK8sParams returns parameters of running Kubernetes API servers.
// It queries only cluster nodes with "controlplane" role.
func GetK8sParams() ([]string, error) {
nodes, err := config.GetNodesInfo()
if err != nil {
return []string{}, err
}
for _, node := range nodes {
if isControlplaneNode(node.Role) {
cmd, err := getK8sCmd(node)
if err != nil {
return []string{}, err
}
if len(cmd) > 0 {
i := bytes.Index(cmd, []byte(k8sProcess))
if i == -1 {
return []string{}, errors.New("missing " + k8sProcess + " command")
}
return btos(cmd[i+len(k8sProcess):]), nil
}
}
}
return []string{}, nil
}
func isControlplaneNode(roles []string) bool {
for _, role := range roles {
if role == controlplane {
return true
}
}
return false
}
func getK8sCmd(node config.NodeInfo) ([]byte, error) {
path, err := expandPath(node.SSHKeyPath)
if err != nil {
return nil, err
}
pubKey, err := parsePublicKey(path)
if err != nil {
return nil, err
}
khPath, err := expandPath(knownHostsFile)
if err != nil {
return nil, err
}
hostKeyCallback, err := kh.New(khPath)
if err != nil {
return nil, err
}
config := &ssh.ClientConfig{
User: node.User,
Auth: []ssh.AuthMethod{pubKey},
HostKeyCallback: hostKeyCallback,
}
conn, err := ssh.Dial("tcp", node.Address+":"+node.Port, config)
if err != nil {
return nil, err
}
defer conn.Close()
out, err := runCommand(dockerInspectCmd, conn)
if err != nil {
return nil, err
}
return out, nil
}
func expandPath(path string) (string, error) {
if len(path) == 0 || path[0] != '~' {
return path, nil
}
usr, err := user.Current()
if err != nil {
return "", err
}
return filepath.Join(usr.HomeDir, path[1:]), nil
}
func parsePublicKey(path string) (ssh.AuthMethod, error) {
key, err := ioutil.ReadFile(path)
if err != nil {
return nil, err
}
signer, err := ssh.ParsePrivateKey(key)
if err != nil {
return nil, err
}
return ssh.PublicKeys(signer), nil
}
func runCommand(cmd string, conn *ssh.Client) ([]byte, error) {
sess, err := conn.NewSession()
if err != nil {
return nil, err
}
defer sess.Close()
out, err := sess.Output(cmd)
if err != nil {
return nil, err
}
return out, nil
}
// btos converts slice of bytes to slice of strings split by white space characters.
func btos(in []byte) []string {
var out []string
for _, b := range bytes.Fields(in) {
out = append(out, string(b))
}
return out
}
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