feat: add an API for reloading plugin (#3749)

#### What type of PR is this?
/kind feature
/area core
/area plugin
/kind api-change
#### What this PR does / why we need it:
新增 reload 插件的 API

how to test it?
通过以下 API 测试是否可以在不重启 Halo 的情况下使新改动的插件代码生效
```shell
./gradlew clean build && curl -u your-name:your-password -X PUT http://127.0.0.1:8090/apis/api.console.halo.run/v1alpha1/plugins/{plugin-name}/reload
```
#### Which issue(s) this PR fixes:

Fixes #3748

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

```release-note
None
```

application/src/main/java/run/halo/app/core/extension/endpoint/PluginEndpoint.java

@@ -123,6 +123,19 @@ public class PluginEndpoint implements CustomEndpoint {
                     .response(responseBuilder()
                         .implementation(ConfigMap.class))
             )
+            .PUT("plugins/{name}/reload", this::reload,
+                builder -> builder.operationId("reloadPlugin")
+                    .description("Reload a plugin by name.")
+                    .tag(tag)
+                    .parameter(parameterBuilder()
+                        .name("name")
+                        .in(ParameterIn.PATH)
+                        .required(true)
+                        .implementation(String.class)
+                    )
+                    .response(responseBuilder()
+                        .implementation(Plugin.class))
+            )
             .GET("plugins", this::list, builder -> {
                 builder.operationId("ListPlugins")
                     .tag(tag)
@@ -164,6 +177,11 @@ public class PluginEndpoint implements CustomEndpoint {
             .build();
     }
 
+    private Mono<ServerResponse> reload(ServerRequest serverRequest) {
+        var name = serverRequest.pathVariable("name");
+        return ServerResponse.ok().body(pluginService.reload(name), Plugin.class);
+    }
+
     private Mono<ServerResponse> listPresets(ServerRequest request) {
         return ServerResponse.ok().body(pluginService.getPresets(), Plugin.class);
     }

application/src/main/java/run/halo/app/core/extension/service/PluginService.java

@@ -1,6 +1,7 @@
 package run.halo.app.core.extension.service;
 
 import java.nio.file.Path;
+import org.springframework.web.server.ServerWebInputException;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import run.halo.app.core.extension.Plugin;
@@ -27,4 +28,16 @@ public interface PluginService {
 
     Mono<Plugin> upgrade(String name, Path path);
 
+    /**
+     * <p>Reload a plugin by name.</p>
+     * Note that this method will set <code>spec.enabled</code> to true it means that the plugin
+     * will be started.
+     *
+     * @param name plugin name
+     * @return an updated plugin reloaded from plugin path
+     * @throws ServerWebInputException if plugin not found by the given name
+     * @see Plugin.PluginSpec#setEnabled(Boolean)
+     * @see run.halo.app.plugin.HaloPluginManager#reloadPlugin(String)
+     */
+    Mono<Plugin> reload(String name);
 }

application/src/main/java/run/halo/app/core/extension/service/impl/PluginServiceImpl.java

@@ -9,7 +9,9 @@ import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.time.Duration;
 import java.util.Objects;
+import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.pf4j.PluginWrapper;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
 import org.springframework.retry.RetryException;
@@ -30,11 +32,13 @@ import run.halo.app.infra.exception.PluginAlreadyExistsException;
 import run.halo.app.infra.exception.UnsatisfiedAttributeValueException;
 import run.halo.app.infra.utils.FileUtils;
 import run.halo.app.infra.utils.VersionUtils;
+import run.halo.app.plugin.HaloPluginManager;
 import run.halo.app.plugin.PluginProperties;
 import run.halo.app.plugin.YamlPluginFinder;
 
 @Slf4j
 @Component
+@RequiredArgsConstructor
 public class PluginServiceImpl implements PluginService {
 
     private static final String PRESET_LOCATION_PREFIX = "classpath:/presets/plugins/";
@@ -46,12 +50,7 @@ public class PluginServiceImpl implements PluginService {
 
     private final PluginProperties pluginProperties;
 
-    public PluginServiceImpl(ReactiveExtensionClient client,
-        SystemVersionSupplier systemVersion, PluginProperties pluginProperties) {
-        this.client = client;
-        this.systemVersion = systemVersion;
-        this.pluginProperties = pluginProperties;
-    }
+    private final HaloPluginManager pluginManager;
 
     @Override
     public Flux<Plugin> getPresets() {
@@ -123,6 +122,25 @@ public class PluginServiceImpl implements PluginService {
         });
     }
 
+    @Override
+    public Mono<Plugin> reload(String name) {
+        PluginWrapper pluginWrapper = pluginManager.getPlugin(name);
+        if (pluginWrapper == null) {
+            return Mono.error(() -> new ServerWebInputException(
+                "The given plugin with name " + name + " was not found."));
+        }
+        YamlPluginFinder yamlPluginFinder = new YamlPluginFinder();
+        Plugin newPlugin = yamlPluginFinder.find(pluginWrapper.getPluginPath());
+        // reload plugin
+        pluginManager.reloadPlugin(name);
+        return client.get(Plugin.class, name)
+            .flatMap(plugin -> {
+                newPlugin.getMetadata().setVersion(plugin.getMetadata().getVersion());
+                newPlugin.getSpec().setEnabled(true);
+                return client.update(newPlugin);
+            });
+    }
+
     /**
      * Copy plugin into plugin home.
      *

application/src/main/java/run/halo/app/plugin/HaloPluginManager.java

@@ -353,8 +353,14 @@ public class HaloPluginManager extends DefaultPluginManager
     }
 
     /**
-     * Reload plugin by id,it will be clean up memory resources of plugin and reload plugin from
-     * disk.
+     * <p>Reload plugin by id,it will be clean up memory resources of plugin and reload plugin from
+     * disk.</p>
+     * <p>
+     * Note: This method will not start plugin, you need to start plugin manually.
+     * this is to avoid starting plugins in different places, which will cause thread safety
+     * issues, so all of them are handed over to the
+     * {@link run.halo.app.core.extension.reconciler.PluginReconciler} to start the plugin
+     * </p>
      *
      * @param pluginId plugin id
      * @return plugin startup status
@@ -368,8 +374,7 @@ public class HaloPluginManager extends DefaultPluginManager
         } catch (Exception ex) {
             return null;
         }
-
-        return doStartPlugin(pluginId);
+        return getPlugin(pluginId).getPluginState();
     }
 
     /**

application/src/main/resources/extensions/role-template-plugin.yaml

@@ -16,7 +16,7 @@ rules:
     resources: [ "plugins" ]
     verbs: [ "create", "patch", "update", "delete", "deletecollection" ]
   - apiGroups: [ "api.console.halo.run" ]
-    resources: [ "plugins/upgrade", "plugins/resetconfig", "plugins/config" ]
+    resources: [ "plugins/upgrade", "plugins/resetconfig", "plugins/config", "plugins/reload" ]
     verbs: [ "*" ]
   - apiGroups: [ "api.console.halo.run" ]
     resources: [ "plugin-presets" ]

application/src/test/java/run/halo/app/core/extension/service/impl/PluginServiceImplTest.java

@@ -1,9 +1,12 @@
 package run.halo.app.core.extension.service.impl;
 
 import static java.util.Objects.requireNonNull;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.argThat;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.ArgumentMatchers.isA;
 import static org.mockito.Mockito.lenient;
 import static org.mockito.Mockito.mock;
@@ -23,19 +26,23 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.pf4j.PluginState;
+import org.pf4j.PluginWrapper;
 import org.springframework.web.server.ServerErrorException;
 import org.springframework.web.server.ServerWebInputException;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 import run.halo.app.core.extension.Plugin;
+import run.halo.app.extension.Metadata;
 import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.infra.SystemVersionSupplier;
 import run.halo.app.infra.exception.PluginAlreadyExistsException;
 import run.halo.app.infra.utils.FileUtils;
+import run.halo.app.plugin.HaloPluginManager;
 import run.halo.app.plugin.PluginProperties;
 import run.halo.app.plugin.YamlPluginFinder;
 
@@ -51,6 +58,9 @@ class PluginServiceImplTest {
     @Mock
     PluginProperties pluginProperties;
 
+    @Mock
+    HaloPluginManager pluginManager;
+
     @InjectMocks
     PluginServiceImpl pluginService;
 
@@ -204,4 +214,45 @@ class PluginServiceImplTest {
             verify(client).<Plugin>create(argThat(p -> p.getSpec().getEnabled()));
         }
     }
+
+    @Test
+    void reload() throws IOException, URISyntaxException {
+        var fakePluginUri = requireNonNull(
+            getClass().getClassLoader().getResource("plugin/plugin-0.0.2")).toURI();
+        Path tempDirectory = Files.createTempDirectory("halo-ut-plugin-service-impl-");
+        Path fakePluginPath = tempDirectory.resolve("plugin-0.0.2.jar");
+        try {
+            FileUtils.jar(Paths.get(fakePluginUri), tempDirectory.resolve("plugin-0.0.2.jar"));
+
+            final String pluginName = "fake-plugin";
+            PluginWrapper pluginWrapper = mock(PluginWrapper.class);
+            when(pluginManager.getPlugin(eq(pluginName))).thenReturn(pluginWrapper);
+            when(pluginWrapper.getPluginPath()).thenReturn(fakePluginPath);
+
+            Plugin plugin = new Plugin();
+            plugin.setMetadata(new Metadata());
+            plugin.getMetadata().setName(pluginName);
+            plugin.setSpec(new Plugin.PluginSpec());
+            plugin.getSpec().setEnabled(false);
+            plugin.getSpec().setDisplayName("Fake Plugin");
+
+            when(client.get(eq(Plugin.class), eq(pluginName))).thenReturn(Mono.just(plugin));
+            when(client.update(any(Plugin.class))).thenReturn(Mono.empty());
+
+            pluginService.reload(pluginName).block();
+
+            verify(pluginManager).reloadPlugin(eq(pluginName));
+            verify(client).get(eq(Plugin.class), eq(pluginName));
+
+            ArgumentCaptor<Plugin> captor = ArgumentCaptor.forClass(Plugin.class);
+            verify(client).update(captor.capture());
+
+            Plugin updatedPlugin = captor.getValue();
+            assertThat(updatedPlugin.getSpec().getEnabled()).isTrue();
+            assertThat(updatedPlugin.getSpec().getDisplayName()).isEqualTo("Fake Display Name");
+            assertThat(updatedPlugin.getSpec().getDescription()).isEqualTo("Fake description");
+        } finally {
+            FileUtils.deleteRecursivelyAndSilently(tempDirectory);
+        }
+    }
 }