Support obtaining plugins root in plugins (#6269)

#### What type of PR is this?

/kind feature
/kind api-change
/area core
/area plugin

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

This PR supports obtaining plugins root in plugins. Below is an example in plugin:

```java
@Component
class PluginsRootGetterDemo {

    private final PluginsRootGetter pluginsRootGetter;

    PluginsRootGetterDemo(PluginsRootGetter pluginsRootGetter) {
        this.pluginsRootGetter = pluginsRootGetter;
    }

}
```

Meanwhile, I remove the `PluginProperties#pluginsRoot` for a clear way to obtain plugins root.

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

```release-note
支持在插件中获取插件根目录
```

api/src/main/java/run/halo/app/plugin/PluginsRootGetter.java

@@ -0,0 +1,14 @@
+package run.halo.app.plugin;
+
+import java.nio.file.Path;
+import java.util.function.Supplier;
+
+/**
+ * An interface to get the root path of plugins.
+ *
+ * @author johnniang
+ * @since 2.18.0
+ */
+public interface PluginsRootGetter extends Supplier<Path> {
+
+}

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

@@ -13,7 +13,6 @@ import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.time.Clock;
 import java.time.Duration;
 import java.util.ArrayList;
@@ -61,8 +60,8 @@ 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.PluginConst;
-import run.halo.app.plugin.PluginProperties;
 import run.halo.app.plugin.PluginUtils;
+import run.halo.app.plugin.PluginsRootGetter;
 import run.halo.app.plugin.SpringPluginManager;
 import run.halo.app.plugin.YamlPluginDescriptorFinder;
 import run.halo.app.plugin.YamlPluginFinder;
@@ -79,7 +78,7 @@ public class PluginServiceImpl implements PluginService, InitializingBean, Dispo
 
     private final SystemVersionSupplier systemVersion;
 
-    private final PluginProperties pluginProperties;
+    private final PluginsRootGetter pluginsRootGetter;
 
     private final SpringPluginManager pluginManager;
 
@@ -93,11 +92,13 @@ public class PluginServiceImpl implements PluginService, InitializingBean, Dispo
 
     private Clock clock = Clock.systemUTC();
 
-    public PluginServiceImpl(ReactiveExtensionClient client, SystemVersionSupplier systemVersion,
-        PluginProperties pluginProperties, SpringPluginManager pluginManager) {
+    public PluginServiceImpl(ReactiveExtensionClient client,
+        SystemVersionSupplier systemVersion,
+        PluginsRootGetter pluginsRootGetter,
+        SpringPluginManager pluginManager) {
         this.client = client;
         this.systemVersion = systemVersion;
-        this.pluginProperties = pluginProperties;
+        this.pluginsRootGetter = pluginsRootGetter;
         this.pluginManager = pluginManager;
 
         this.jsBundleCache = new BundleCache(".js");
@@ -424,7 +425,7 @@ public class PluginServiceImpl implements PluginService, InitializingBean, Dispo
         return Mono.fromCallable(
                 () -> {
                     var fileName = PluginUtils.generateFileName(plugin);
-                    var pluginRoot = Paths.get(pluginProperties.getPluginsRoot());
+                    var pluginRoot = pluginsRootGetter.get();
                     try {
                         Files.createDirectories(pluginRoot);
                     } catch (IOException e) {

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

@@ -1,12 +1,10 @@
 package run.halo.app.plugin;
 
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Stack;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.commons.lang3.StringUtils;
 import org.pf4j.CompoundPluginLoader;
 import org.pf4j.CompoundPluginRepository;
 import org.pf4j.DefaultPluginManager;
@@ -46,13 +44,16 @@ public class HaloPluginManager extends DefaultPluginManager implements SpringPlu
 
     private final PluginProperties pluginProperties;
 
+    private final PluginsRootGetter pluginsRootGetter;
+
     public HaloPluginManager(ApplicationContext rootContext,
         PluginProperties pluginProperties,
-        SystemVersionSupplier systemVersionSupplier) {
+        SystemVersionSupplier systemVersionSupplier, PluginsRootGetter pluginsRootGetter) {
         this.pluginProperties = pluginProperties;
         this.rootContext = rootContext;
         // We have to initialize share context lazily because the root context has not refreshed
         this.sharedContext = Lazy.of(() -> SharedApplicationContextFactory.create(rootContext));
+        this.pluginsRootGetter = pluginsRootGetter;
         super.runtimeMode = pluginProperties.getRuntimeMode();
 
         setExactVersionAllowed(pluginProperties.isExactVersionAllowed());
@@ -124,11 +125,7 @@ public class HaloPluginManager extends DefaultPluginManager implements SpringPlu
 
     @Override
     protected List<Path> createPluginsRoot() {
-        var pluginsRoot = pluginProperties.getPluginsRoot();
-        if (StringUtils.isNotBlank(pluginsRoot)) {
-            return List.of(Paths.get(pluginsRoot));
-        }
-        return super.createPluginsRoot();
+        return List.of(pluginsRootGetter.get());
     }
 
     @Override

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

@@ -45,8 +45,11 @@ public class PluginAutoConfiguration {
     @Bean
     public SpringPluginManager pluginManager(ApplicationContext context,
         SystemVersionSupplier systemVersionSupplier,
-        PluginProperties pluginProperties) {
-        return new HaloPluginManager(context, pluginProperties, systemVersionSupplier);
+        PluginProperties pluginProperties,
+        PluginsRootGetter pluginsRootGetter) {
+        return new HaloPluginManager(
+            context, pluginProperties, systemVersionSupplier, pluginsRootGetter
+        );
     }
 
     @Bean

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

@@ -60,10 +60,4 @@ public class PluginProperties {
      */
     private RuntimeMode runtimeMode = RuntimeMode.DEPLOYMENT;
 
-    /**
-     * Plugin root directory: default “plugins”; when non-jar mode plugin, the value should be an
-     * absolute directory address.
-     */
-    private String pluginsRoot;
-
 }

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

@@ -0,0 +1,28 @@
+package run.halo.app.plugin;
+
+import java.nio.file.Path;
+import org.springframework.lang.NonNull;
+import org.springframework.stereotype.Component;
+import run.halo.app.infra.properties.HaloProperties;
+
+/**
+ * Default implementation of {@link PluginsRootGetter}.
+ *
+ * @author johnniang
+ */
+@Component
+public class PluginsRootGetterImpl implements PluginsRootGetter {
+
+    private final HaloProperties haloProperties;
+
+    public PluginsRootGetterImpl(HaloProperties haloProperties) {
+        this.haloProperties = haloProperties;
+    }
+
+    @Override
+    @NonNull
+    public Path get() {
+        return haloProperties.getWorkDir().resolve("plugins");
+    }
+
+}

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

@@ -62,6 +62,10 @@ public enum SharedApplicationContextFactory {
             rootContext.getBean(CacheManager.class));
         beanFactory.registerSingleton("loginHandlerEnhancer",
             rootContext.getBean(LoginHandlerEnhancer.class));
+        rootContext.getBeanProvider(PluginsRootGetter.class)
+            .ifUnique(pluginsRootGetter ->
+                beanFactory.registerSingleton("pluginsRootGetter", pluginsRootGetter)
+            );
         // TODO add more shared instance here
 
         sharedContext.refresh();

application/src/main/resources/application.yaml

@@ -34,8 +34,6 @@ spring:
 
 halo:
   work-dir: ${user.home}/.halo2
-  plugin:
-    plugins-root: ${halo.work-dir}/plugins
   attachment:
     resource-mappings:
       - pathPattern: /upload/**

application/src/test/java/run/halo/app/core/extension/endpoint/PluginEndpointTest.java

@@ -55,15 +55,11 @@ import run.halo.app.extension.Metadata;
 import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.infra.SystemVersionSupplier;
 import run.halo.app.infra.utils.FileUtils;
-import run.halo.app.plugin.PluginProperties;
 
 @Slf4j
 @ExtendWith(MockitoExtension.class)
 class PluginEndpointTest {
 
-    @Mock
-    PluginProperties pluginProperties;
-
     @Mock
     private ReactiveExtensionClient client;
 
@@ -221,8 +217,6 @@ class PluginEndpointTest {
 
             lenient().when(systemVersionSupplier.get()).thenReturn(Version.valueOf("0.0.0"));
             tempDirectory = Files.createTempDirectory("halo-test-plugin-upgrade-");
-            lenient().when(pluginProperties.getPluginsRoot())
-                .thenReturn(tempDirectory.resolve("plugins").toString());
             plugin002 = tempDirectory.resolve("plugin-0.0.2.jar");
 
             var plugin002Uri = requireNonNull(

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

@@ -58,7 +58,7 @@ 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.PluginConst;
-import run.halo.app.plugin.PluginProperties;
+import run.halo.app.plugin.PluginsRootGetter;
 import run.halo.app.plugin.SpringPluginManager;
 import run.halo.app.plugin.YamlPluginFinder;
 
@@ -72,7 +72,7 @@ class PluginServiceImplTest {
     ReactiveExtensionClient client;
 
     @Mock
-    PluginProperties pluginProperties;
+    PluginsRootGetter pluginsRootGetter;
 
     @Mock
     SpringPluginManager pluginManager;
@@ -123,9 +123,6 @@ class PluginServiceImplTest {
                 getClass().getClassLoader().getResource("plugin/plugin-0.0.2")).toURI();
             FileUtils.jar(Paths.get(fakePluingUri), tempDirectory.resolve("plugin-0.0.2.jar"));
 
-            lenient().when(pluginProperties.getPluginsRoot())
-                .thenReturn(tempDirectory.resolve("plugins").toString());
-
             lenient().when(systemVersionSupplier.get()).thenReturn(Version.valueOf("0.0.0"));
         }
 
@@ -144,6 +141,7 @@ class PluginServiceImplTest {
 
         @Test
         void installWhenPluginNotExist() {
+            when(pluginsRootGetter.get()).thenReturn(tempDirectory.resolve("plugins"));
             when(client.fetch(Plugin.class, "fake-plugin")).thenReturn(Mono.empty());
             var createdPlugin = mock(Plugin.class);
             when(client.create(isA(Plugin.class))).thenReturn(Mono.just(createdPlugin));
@@ -154,7 +152,6 @@ class PluginServiceImplTest {
 
             verify(client).fetch(Plugin.class, "fake-plugin");
             verify(systemVersionSupplier).get();
-            verify(pluginProperties).getPluginsRoot();
             verify(client).create(isA(Plugin.class));
         }
 
@@ -181,6 +178,8 @@ class PluginServiceImplTest {
 
         @Test
         void upgradeNormally() {
+            when(pluginsRootGetter.get()).thenReturn(tempDirectory.resolve("plugins"));
+
             var oldFakePlugin = createPlugin("fake-plugin", plugin -> {
                 plugin.getSpec().setEnabled(true);
                 plugin.getSpec().setVersion("0.0.1");

application/src/test/java/run/halo/app/plugin/DefaultPluginApplicationContextFactoryTest.java

@@ -22,7 +22,7 @@ class DefaultPluginApplicationContextFactoryTest {
 
     @BeforeEach
     void setUp() {
-        factory = new DefaultPluginApplicationContextFactory((SpringPluginManager) pluginManager);
+        factory = new DefaultPluginApplicationContextFactory(pluginManager);
     }
 
     @Test
@@ -41,6 +41,7 @@ class DefaultPluginApplicationContextFactoryTest {
 
         assertInstanceOf(PluginApplicationContext.class, context);
         assertNotNull(context.getBeanProvider(SearchService.class).getIfUnique());
+        assertNotNull(context.getBeanProvider(PluginsRootGetter.class).getIfUnique());
         // TODO Add more assertions here.
     }
 

application/src/test/java/run/halo/app/plugin/PluginsRootGetterImplTest.java

@@ -0,0 +1,30 @@
+package run.halo.app.plugin;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.when;
+
+import java.nio.file.Paths;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import run.halo.app.infra.properties.HaloProperties;
+
+@ExtendWith(MockitoExtension.class)
+class PluginsRootGetterImplTest {
+
+    @Mock
+    HaloProperties haloProperties;
+
+    @InjectMocks
+    PluginsRootGetterImpl pluginsRootGetter;
+
+    @Test
+    void shouldGetterPluginsRootCorrectly() {
+        var haloWorkDir = Paths.get("halo-work-dir");
+        when(haloProperties.getWorkDir()).thenReturn(haloWorkDir);
+        assertEquals(haloWorkDir.resolve("plugins"), pluginsRootGetter.get());
+    }
+
+}