Support restarting Halo (#4361)

#### What type of PR is this?

/kind feature
/area core
/milestone 2.9.x

#### What this PR does / why we need it:

Support restarting Halo and enable restart endpoint by default.

Restart endpoint detail:

request uri: `/actuator/restart`
request method: `POST`

Please note that memory usage may slightly increase after restarting Halo.

#### Does this PR introduce a user-facing change?

```release-note
支持在线重启 Halo。
```

application/build.gradle

@@ -52,8 +52,6 @@ dependencies {
     annotationProcessor "org.springframework.boot:spring-boot-configuration-processor"
     annotationProcessor "org.springframework:spring-context-indexer"
 
-    developmentOnly 'org.springframework.boot:spring-boot-devtools'
-
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
     testImplementation 'org.springframework.security:spring-security-test'
     testImplementation 'io.projectreactor:reactor-test'

application/src/main/java/run/halo/app/actuator/RestartEndpoint.java

@@ -0,0 +1,77 @@
+package run.halo.app.actuator;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.Collections;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.actuate.endpoint.annotation.WriteOperation;
+import org.springframework.boot.actuate.endpoint.web.annotation.WebEndpoint;
+import org.springframework.boot.context.event.ApplicationStartedEvent;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationListener;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.stereotype.Component;
+import run.halo.app.Application;
+
+@WebEndpoint(id = "restart")
+@Component
+@Slf4j
+public class RestartEndpoint implements ApplicationListener<ApplicationStartedEvent> {
+
+    private SpringApplication application;
+
+    private String[] args;
+
+    private ConfigurableApplicationContext context;
+
+    @WriteOperation
+    public Object restart() {
+        var threadGroup = new ThreadGroup("RestartGroup");
+        var thread = new Thread(threadGroup, this::doRestart, "restartMain");
+        thread.setDaemon(false);
+        thread.setContextClassLoader(Application.class.getClassLoader());
+        thread.start();
+        return Collections.singletonMap("message", "Restarting");
+    }
+
+    private synchronized void doRestart() {
+        log.info("Restarting...");
+        if (this.context != null) {
+            try {
+                closeRecursively(this.context);
+                var shutdownHandlers = SpringApplication.getShutdownHandlers();
+                if (shutdownHandlers instanceof Runnable runnable) {
+                    // clear closedContext in org.springframework.boot.SpringApplicationShutdownHook
+                    runnable.run();
+                }
+                this.context = this.application.run(args);
+                log.info("Restarted");
+            } catch (Throwable t) {
+                log.error("Failed to restart.", t);
+            }
+        }
+    }
+
+    private static void closeRecursively(ApplicationContext ctx) {
+        while (ctx != null) {
+            if (ctx instanceof Closeable closeable) {
+                try {
+                    closeable.close();
+                } catch (IOException e) {
+                    log.error("Cannot close context: {}", ctx.getId(), e);
+                }
+            }
+            ctx = ctx.getParent();
+        }
+    }
+
+    @Override
+    public void onApplicationEvent(ApplicationStartedEvent event) {
+        if (this.context == null) {
+            this.application = event.getSpringApplication();
+            this.args = event.getArgs();
+            this.context = event.getApplicationContext();
+        }
+    }
+}

application/src/main/resources/application.yaml

@@ -64,7 +64,7 @@ management:
   endpoints:
     web:
       exposure:
-        include: ["health", "info", "startup", "globalinfo", "logfile", "shutdown"]
+        include: ["health", "info", "startup", "globalinfo", "logfile", "shutdown", "restart"]
   endpoint:
     shutdown:
       enabled: true

console/src/locales/en.yaml

@@ -1003,9 +1003,9 @@ core:
         description: Are you sure you want to delete the backup?
       restore:
         title: Restore successfully
-        description: After successful restore, you need to restart Halo to load the system resources normally. After clicking OK, we will automatically stop running Halo.
-      shutdown:
-        toast_success: Requested to shutdown operation
+        description: After successful restore, you need to restart Halo to load the system resources normally. After clicking OK, we will automatically restart Halo.
+      restart:
+        toast_success: Requested to restart
     list:
       phases:
         pending: Pending
@@ -1018,7 +1018,7 @@ core:
       tips:
         first: 1. The restore process may last for a long time, please do not refresh the page during this period.
         second: 2. During the restore process, although the existing data will not be cleaned up, if there is a conflict, the data will be overwritten.
-        third: 3. After the restore is completed, you will be prompted to stop running Halo, and you may need to run it manually after stopping.
+        third: 3. After the restore is completed, you need to restart Halo to load the system resources normally.
         complete: Restore completed, waiting for restart...
       start: Start restore
   exception:

console/src/locales/zh-CN.yaml

@@ -1003,9 +1003,9 @@ core:
         description: 确定要删除该备份吗？
       restore:
         title: 恢复成功
-        description: 恢复成功之后，需要重启一下 Halo 才能够正常加载系统资源，点击确定之后我们会自动停止运行 Halo
-      shutdown:
-        toast_success: 已请求停止运行
+        description: 恢复成功之后，需要重启一下 Halo 才能够正常加载系统资源，点击确定之后我们会自动重启 Halo。
+      restart:
+        toast_success: 已请求重启
     list:
       phases:
         pending: 准备中
@@ -1018,7 +1018,7 @@ core:
       tips:
         first: 1. 恢复过程可能会持续较长时间，期间请勿刷新页面。
         second: 2. 在恢复的过程中，虽然已有的数据不会被清理掉，但如果有冲突的数据将被覆盖。
-        third: 3. 恢复完成之后会提示停止运行 Halo，停止之后可能需要手动运行。
+        third: 3. 恢复完成之后需要重启 Halo 才能够正常加载系统资源。
         complete: 恢复完成，等待重启...
       start: 开始恢复
   exception:

console/src/locales/zh-TW.yaml

@@ -1003,9 +1003,9 @@ core:
         description: 確定要刪除此備份嗎？
       restore:
         title: 還原成功
-        description: 還原成功後，需要重新啟動 Halo 才能正常載入系統資源，點擊確定後我們會自動停止運行 Halo。
-      shutdown:
-        toast_success: 已請求停止運行
+        description: 還原成功後，需要重新啟動 Halo 才能正常載入系統資源，點擊確定之後，我們會自動重啟 Halo。
+      restart:
+        toast_success: 已請求重啟
     list:
       phases:
         pending: 準備中
@@ -1018,7 +1018,7 @@ core:
       tips:
         first: 1. 還原過程可能需要較長時間，期間請勿重新整理頁面。
         second: 2. 在還原過程中，雖然已有的資料不會被清除，但若有衝突的資料將被覆蓋。
-        third: 3. 還原完成後會提示停止運行 Halo，停止後可能需要手動啟動。
+        third: 3. 還原完成後需要重新啟動 Halo 才能正常載入系統資源。
         complete: 恢復完成，等待重啟...
       start: 開始還原
   exception:

console/src/modules/system/backup/tabs/Restore.vue

@@ -25,8 +25,8 @@ const onUploaded = () => {
 };
 
 async function handleShutdown() {
-  await axios.post(`/actuator/shutdown`);
-  Toast.success(t("core.backup.operations.shutdown.toast_success"));
+  await axios.post(`/actuator/restart`);
+  Toast.success(t("core.backup.operations.restart.toast_success"));
 
   setTimeout(() => {
     complete.value = true;