/
env.go
164 lines (137 loc) · 3.83 KB
/
env.go
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package config
import (
"errors"
"fmt"
"io"
"log/slog"
"os"
"strings"
"github.com/chitoku-k/slack-to-ssh/service"
"golang.org/x/crypto/ssh"
)
const DefaultSSHPort = "22"
type Environment struct {
SSH SSH
SlackActions []service.SlackAction
SlackAppSecret string
Port string
TLSCert string
TLSKey string
}
type SSH struct {
HostName string
Port string
Username string
KnownHosts []ssh.PublicKey
PrivateKey ssh.Signer
}
func Get() (Environment, error) {
var missing []string
var env Environment
var sshKnownHostsPath string
var sshPrivateKeyPath, sshPrivateKeyPassphrasePath string
for k, v := range map[string]*string{
"SSH_PORT": &env.SSH.Port,
"SSH_KNOWN_HOSTS_FILE": &sshKnownHostsPath,
"SSH_PRIVATE_KEY_PASSPHRASE_FILE": &sshPrivateKeyPassphrasePath,
"TLS_CERT": &env.TLSCert,
"TLS_KEY": &env.TLSKey,
} {
*v = os.Getenv(k)
}
for k, v := range map[string]*string{
"SSH_HOSTNAME": &env.SSH.HostName,
"SSH_USERNAME": &env.SSH.Username,
"SSH_PRIVATE_KEY_FILE": &sshPrivateKeyPath,
"SLACK_APP_SECRET": &env.SlackAppSecret,
"PORT": &env.Port,
} {
*v = os.Getenv(k)
if *v == "" {
missing = append(missing, k)
}
}
for i := 0; ; i++ {
name := os.Getenv(fmt.Sprintf("SLACK_ACTION_%d_NAME", i))
if name == "" {
break
}
action := service.SlackAction{Name: name}
for k, v := range map[string]*string{
fmt.Sprintf("SLACK_ACTION_%d_COMMAND", i): &action.Command,
} {
*v = os.Getenv(k)
if *v == "" {
missing = append(missing, k)
}
}
for k, v := range map[string]*string{
fmt.Sprintf("SLACK_ACTION_%d_ATTACHMENT_TEXT", i): &action.AttachmentText,
} {
*v = os.Getenv(k)
}
env.SlackActions = append(env.SlackActions, action)
}
if len(missing) > 0 {
return env, errors.New("missing env(s): " + strings.Join(missing, ", "))
}
if len(env.SlackActions) == 0 {
return env, errors.New("missing actions: at least 1 action is required")
}
if sshKnownHostsPath != "" {
knownHosts, err := os.ReadFile(sshKnownHostsPath)
if err != nil {
return env, fmt.Errorf("failed to read known hosts %q: %w", sshKnownHostsPath, err)
}
for knownHosts != nil {
publicKey, rest, err := parseSSHKnownHosts(knownHosts, env.SSH.HostName)
if err != nil {
return env, fmt.Errorf("failed to parse known hosts: %w", err)
}
if publicKey != nil {
env.SSH.KnownHosts = append(env.SSH.KnownHosts, publicKey)
}
knownHosts = rest
}
} else {
slog.Warn("SSH host key verification is disabled. Consider configuring SSH_KNOWN_HOSTS_FILE.")
}
sshPrivateKey, err := os.ReadFile(sshPrivateKeyPath)
if err != nil {
return env, fmt.Errorf("failed to read private key %q: %w", sshPrivateKeyPath, err)
}
if sshPrivateKeyPassphrasePath != "" {
sshPrivateKeyPassphrase, err := os.ReadFile(sshPrivateKeyPassphrasePath)
if err != nil {
return env, fmt.Errorf("failed to read passphrase %q: %w", sshPrivateKeyPassphrasePath, err)
}
env.SSH.PrivateKey, err = ssh.ParsePrivateKeyWithPassphrase(sshPrivateKey, sshPrivateKeyPassphrase)
} else {
env.SSH.PrivateKey, err = ssh.ParsePrivateKey(sshPrivateKey)
}
if err != nil {
return env, fmt.Errorf("failed to parse private key %q: %w", sshPrivateKeyPath, err)
}
if env.SSH.Port == "" {
env.SSH.Port = DefaultSSHPort
}
return env, nil
}
func parseSSHKnownHosts(knownHosts []byte, hostname string) (publicKey ssh.PublicKey, rest []byte, err error) {
marker, hosts, publicKey, _, rest, err := ssh.ParseKnownHosts(knownHosts)
if err == io.EOF {
return nil, nil, nil
}
if err != nil {
return nil, rest, err
}
if marker == "revoked" {
return nil, rest, err
}
for _, h := range hosts {
if h == hostname {
return publicKey, rest, err
}
}
return nil, rest, err
}