Merge pull request #7852 from macroscopic64/master

[BAEL-3288] - Graceful Shutdown of a Spring Boot Application

spring-boot-ops-2/src/main/java/com/baeldung/gracefulshutdown/GracefulShutdownApplication.java

@@ -0,0 +1,12 @@
+package com.baeldung.gracefulshutdown;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class GracefulShutdownApplication {
+
+    public static void main(String args[]) {
+        SpringApplication.run(GracefulShutdownApplication.class, args);
+    }
+}

spring-boot-ops-2/src/main/java/com/baeldung/gracefulshutdown/beans/LongRunningProcessBean.java

@@ -0,0 +1,36 @@
+package com.baeldung.gracefulshutdown.beans;
+
+import javax.annotation.PostConstruct;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.task.TaskExecutor;
+import org.springframework.stereotype.Component;
+
+@Component
+public class LongRunningProcessBean {
+
+    private static final Logger LOG = LoggerFactory.getLogger(LongRunningProcessBean.class);
+
+    @Autowired
+    private TaskExecutor taskExecutor;
+
+    @PostConstruct
+    public void runTaskOnStartup() {
+        LOG.info("runTaskOnStartup entering");
+        for (int i = 0; i < 3; i++) {
+            final int processNumber = i;
+            taskExecutor.execute(() -> {
+                try {
+                    LOG.info("Long running process {} using threadpool started", processNumber);
+                    Thread.sleep(60_000);
+                    LOG.info("Long running process {} using threadpool completed", processNumber);
+                } catch (Exception e) {
+                    LOG.error("Error while executing task", e);
+                }
+            });
+        }
+        LOG.info("runTaskOnStartup exiting");
+    }
+}

spring-boot-ops-2/src/main/java/com/baeldung/gracefulshutdown/config/SpringConfiguration.java

@@ -0,0 +1,32 @@
+package com.baeldung.gracefulshutdown.config;
+
+import javax.annotation.PreDestroy;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.task.TaskExecutor;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+
+@Configuration
+public class SpringConfiguration {
+
+    private static final Logger LOG = LoggerFactory.getLogger(SpringConfiguration.class);
+
+    @Bean
+    public TaskExecutor taskExecutor() {
+        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
+        taskExecutor.setCorePoolSize(2);
+        taskExecutor.setMaxPoolSize(2);
+        taskExecutor.setWaitForTasksToCompleteOnShutdown(true);
+        taskExecutor.setAwaitTerminationSeconds(30);
+        taskExecutor.initialize();
+        return taskExecutor;
+    }
+
+    @PreDestroy
+    public void destroy() {
+        LOG.info("Shutdown initiated");
+    }
+}