add timeoutExecutor to prevent deadlocks; fix not using timeout from configuration in TbSendEmailNode

application/src/main/java/org/thingsboard/server/service/mail/DefaultMailService.java

@@ -23,6 +23,7 @@ import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.exception.ExceptionUtils;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.MessageSource;
 import org.springframework.context.annotation.Lazy;
 import org.springframework.core.NestedRuntimeException;
@@ -34,6 +35,7 @@ import org.springframework.stereotype.Service;
 import org.springframework.ui.freemarker.FreeMarkerTemplateUtils;
 import org.thingsboard.rule.engine.api.MailService;
 import org.thingsboard.rule.engine.api.TbEmail;
+import org.thingsboard.rule.engine.mail.TbSendEmailNodeConfiguration;
 import org.thingsboard.server.common.data.AdminSettings;
 import org.thingsboard.server.common.data.ApiFeature;
 import org.thingsboard.server.common.data.ApiUsageRecordKey;
@@ -49,6 +51,7 @@ import org.thingsboard.server.queue.usagestats.TbApiUsageClient;
 import org.thingsboard.server.service.apiusage.TbApiUsageStateService;
 
 import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
 import javax.mail.MessagingException;
 import javax.mail.internet.MimeMessage;
 import java.io.ByteArrayInputStream;
@@ -56,6 +59,8 @@ import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Properties;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
@@ -83,6 +88,11 @@ public class DefaultMailService implements MailService {
     @Autowired
     private MailExecutorService mailExecutorService;
 
+    @Value("${actors.rule.mail_timeout_thread_pool_size}")
+    private int timeoutExecutorPoolSize;
+
+    private ExecutorService timeoutExecutorService;
+
     private JavaMailSenderImpl mailSender;
 
     private String mailFrom;
@@ -99,6 +109,14 @@ public class DefaultMailService implements MailService {
     @PostConstruct
     private void init() {
         updateMailConfiguration();
+        timeoutExecutorService = Executors.newFixedThreadPool(timeoutExecutorPoolSize);
+    }
+
+    @PreDestroy
+    private void destroy() {
+        if (timeoutExecutorService != null) {
+            timeoutExecutorService.shutdown();
+        }
     }
 
     @Override
@@ -262,15 +280,15 @@ public class DefaultMailService implements MailService {
 
     @Override
     public void send(TenantId tenantId, CustomerId customerId, TbEmail tbEmail) throws ThingsboardException {
-        sendMail(tenantId, customerId, tbEmail, this.mailSender);
+        sendMail(tenantId, customerId, tbEmail, this.mailSender, timeout);
     }
 
     @Override
-    public void send(TenantId tenantId, CustomerId customerId, TbEmail tbEmail, JavaMailSender javaMailSender) throws ThingsboardException {
-        sendMail(tenantId, customerId, tbEmail, javaMailSender);
+    public void send(TenantId tenantId, CustomerId customerId, TbEmail tbEmail, JavaMailSender javaMailSender, long timeout) throws ThingsboardException {
+        sendMail(tenantId, customerId, tbEmail, javaMailSender, timeout);
     }
 
-    private void sendMail(TenantId tenantId, CustomerId customerId, TbEmail tbEmail, JavaMailSender javaMailSender) throws ThingsboardException {
+    private void sendMail(TenantId tenantId, CustomerId customerId, TbEmail tbEmail, JavaMailSender javaMailSender, long timeout) throws ThingsboardException {
         if (apiUsageStateService.getApiUsageState(tenantId).isEmailSendEnabled()) {
             try {
                 MimeMessage mailMsg = javaMailSender.createMimeMessage();
@@ -474,10 +492,11 @@ public class DefaultMailService implements MailService {
     }
 
     private void sendMailWithTimeout(JavaMailSender mailSender, MimeMessage msg, long timeout) {
-        var submittedMail = Futures.submit(() -> mailSender.send(msg), mailExecutorService);
+        var submittedMail = timeoutExecutorService.submit(() -> mailSender.send(msg));
         try {
             submittedMail.get(timeout, TimeUnit.MILLISECONDS);
-        } catch (TimeoutException ignored) {
+        } catch (TimeoutException e) {
+            log.debug("Error during mail submission", e);
             throw new RuntimeException("Timeout!");
         } catch (Exception e) {
             throw new RuntimeException(ExceptionUtils.getRootCause(e));

application/src/main/resources/thingsboard.yml

@@ -326,7 +326,9 @@ actors:
     # Specify thread pool size for javascript executor service
     js_thread_pool_size: "${ACTORS_RULE_JS_THREAD_POOL_SIZE:50}"
     # Specify thread pool size for mail sender executor service
-    mail_thread_pool_size: "${ACTORS_RULE_MAIL_THREAD_POOL_SIZE:50}"
+    mail_thread_pool_size: "${ACTORS_RULE_MAIL_THREAD_POOL_SIZE:40}"
+    # Specify thread pool size for mail sender executor service
+    mail_timeout_thread_pool_size: "${ACTORS_RULE_MAIL_TIMEOUT_THREAD_POOL_SIZE:10}"
     # Specify thread pool size for sms sender executor service
     sms_thread_pool_size: "${ACTORS_RULE_SMS_THREAD_POOL_SIZE:50}"
     # Whether to allow usage of system mail service for rules

rule-engine/rule-engine-api/src/main/java/org/thingsboard/rule/engine/api/MailService.java

@@ -47,8 +47,7 @@ public interface MailService {
     void sendTwoFaVerificationEmail(String email, String verificationCode, int expirationTimeSeconds) throws ThingsboardException;
 
     void send(TenantId tenantId, CustomerId customerId, TbEmail tbEmail) throws ThingsboardException;
-
-    void send(TenantId tenantId, CustomerId customerId, TbEmail tbEmail, JavaMailSender javaMailSender) throws ThingsboardException;
+    void send(TenantId tenantId, CustomerId customerId, TbEmail tbEmail, JavaMailSender javaMailSender, long timeout) throws ThingsboardException;
 
     void sendApiFeatureStateEmail(ApiFeature apiFeature, ApiUsageStateValue stateValue, String email, ApiUsageStateMailMessage msg) throws ThingsboardException;
 

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/mail/TbSendEmailNode.java

@@ -88,7 +88,7 @@ public class TbSendEmailNode implements TbNode {
         if (this.config.isUseSystemSmtpSettings()) {
             ctx.getMailService(true).send(ctx.getTenantId(), msg.getCustomerId(), email);
         } else {
-            ctx.getMailService(false).send(ctx.getTenantId(), msg.getCustomerId(), email, this.mailSender);
+            ctx.getMailService(false).send(ctx.getTenantId(), msg.getCustomerId(), email, this.mailSender, config.getTimeout());
         }
     }