feat: publish standalone worker

Separate worker packaging and service lifecycle from the control plane.

app/models/credential_crypto.go

@@ -0,0 +1,97 @@
+package models
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"errors"
+	"io"
+	"os"
+	"strings"
+
+	"rsgit.ru/rsmon/rsmon/config/secrets"
+)
+
+const credentialKeyEnv = "RSMON_CRED_KEY"
+
+// encryptSecret encrypts plaintext with AES-GCM. If no key is configured
+// (dev/test), stores the value with a "plain:" prefix. Production deployments
+// must set RSMON_CRED_KEY or config/secrets.yml crypto.pepper.
+func encryptSecret(plaintext string) (string, error) {
+	key := credentialKey()
+	if key == "" {
+		return "plain:" + plaintext, nil
+	}
+	block, err := aes.NewCipher(deriveKey(key))
+	if err != nil {
+		return "", err
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return "", err
+	}
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return "", err
+	}
+	sealed := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
+	return "enc:" + base64.StdEncoding.EncodeToString(sealed), nil
+}
+
+// decryptSecret decrypts a value produced by encryptSecret. Values without a
+// known prefix are returned as-is for backward compatibility with legacy
+// plaintext records.
+func decryptSecret(stored string) (string, error) {
+	if stored == "" {
+		return "", nil
+	}
+	switch {
+	case strings.HasPrefix(stored, "plain:"):
+		return strings.TrimPrefix(stored, "plain:"), nil
+	case strings.HasPrefix(stored, "enc:"):
+		key := credentialKey()
+		if key == "" {
+			return "", errors.New("credential key not configured but secret is encrypted")
+		}
+		raw, err := base64.StdEncoding.DecodeString(strings.TrimPrefix(stored, "enc:"))
+		if err != nil {
+			return "", err
+		}
+		block, err := aes.NewCipher(deriveKey(key))
+		if err != nil {
+			return "", err
+		}
+		gcm, err := cipher.NewGCM(block)
+		if err != nil {
+			return "", err
+		}
+		if len(raw) < gcm.NonceSize() {
+			return "", errors.New("ciphertext too short")
+		}
+		nonce, ciphertext := raw[:gcm.NonceSize()], raw[gcm.NonceSize():]
+		plaintext, err := gcm.Open(nil, nonce, ciphertext, nil)
+		if err != nil {
+			return "", err
+		}
+		return string(plaintext), nil
+	default:
+		return stored, nil
+	}
+}
+
+func deriveKey(s string) []byte {
+	h := sha256.Sum256([]byte(s))
+	return h[:32]
+}
+
+func credentialKey() string {
+	if k := os.Getenv(credentialKeyEnv); k != "" {
+		return k
+	}
+	if secrets.Crypto != nil && secrets.Crypto.Pepper != "" {
+		return secrets.Crypto.Pepper
+	}
+	return ""
+}