fix: add retry + User-Agent to Legacy provider doRequest (same P0.1 fix)

internal/core/client.go

@@ -173,44 +173,82 @@ func (c *UniversalClient) CreateGenericInstance(ctx context.Context, serviceId i
 }
 
 func (c *UniversalClient) doRequest(ctx context.Context, method, path string, payload interface{}) ([]byte, http.Header, error) {
-	var body io.Reader
-	if payload != nil {
-		b, err := json.Marshal(payload)
+	// User-Agent: браузерный, чтобы пройти DDoS-Guard (см. docs/ops/API_TOKENS.md).
+	const userAgent = "Mozilla/5.0 (compatible; Terraform-Provider-Nubes)"
+	const maxRetries = 3
+	baseDelay := 2 * time.Second
+
+	var lastErr error
+	for attempt := 0; attempt <= maxRetries; attempt++ {
+		if attempt > 0 {
+			delay := baseDelay * time.Duration(1<<(attempt-1))
+			select {
+			case <-time.After(delay):
+			case <-ctx.Done():
+				return nil, nil, ctx.Err()
+			}
+		}
+
+		var body io.Reader
+		if payload != nil {
+			b, err := json.Marshal(payload)
+			if err != nil {
+				return nil, nil, err
+			}
+			body = bytes.NewBuffer(b)
+		}
+
+		req, err := http.NewRequestWithContext(ctx, method, c.ApiEndpoint+path, body)
 		if err != nil {
 			return nil, nil, err
 		}
-		body = bytes.NewBuffer(b)
+
+		req.Close = true
+		req.Header.Set("Content-Type", "application/json")
+		req.Header.Set("User-Agent", userAgent)
+		if c.ApiToken != "" {
+			req.Header.Set("Authorization", "Bearer "+c.ApiToken)
+		}
+
+		resp, err := c.HttpClient.Do(req)
+		if err != nil {
+			lastErr = err
+			if attempt < maxRetries {
+				continue
+			}
+			return nil, nil, err
+		}
+
+		respBody, err := io.ReadAll(resp.Body)
+		resp.Body.Close()
+		if err != nil {
+			lastErr = err
+			if attempt < maxRetries {
+				continue
+			}
+			return nil, nil, err
+		}
+
+		if resp.StatusCode >= 400 {
+			err := fmt.Errorf("API error %d: %s", resp.StatusCode, string(respBody))
+			if attempt < maxRetries && method == "GET" && isRetryable(resp.StatusCode) {
+				lastErr = err
+				continue
+			}
+			return nil, nil, err
+		}
+
+		return respBody, resp.Header, nil
 	}
 
-	req, err := http.NewRequestWithContext(ctx, method, c.ApiEndpoint+path, body)
-	if err != nil {
-		return nil, nil, err
-	}
+	return nil, nil, fmt.Errorf("doRequest failed after %d retries: %w", maxRetries, lastErr)
+}
 
-	// Force close connection
-	req.Close = true
-
-	req.Header.Set("Content-Type", "application/json")
-	if c.ApiToken != "" {
-		req.Header.Set("Authorization", "Bearer "+c.ApiToken)
-	}
-
-	resp, err := c.HttpClient.Do(req)
-	if err != nil {
-		return nil, nil, err
-	}
-	defer resp.Body.Close()
-
-	respBody, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	if resp.StatusCode >= 400 {
-		return nil, nil, fmt.Errorf("API error %d: %s", resp.StatusCode, string(respBody))
-	}
-
-	return respBody, resp.Header, nil
+func isRetryable(statusCode int) bool {
+	return statusCode == http.StatusTooManyRequests ||
+		statusCode == http.StatusServiceUnavailable ||
+		statusCode == http.StatusBadGateway ||
+		statusCode == http.StatusGatewayTimeout
 }
 
 // ===== UNIVERSAL FLOW (APPEND-ONLY) =====