feat: add plugin setting support (#2238)

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#### What type of PR is this?
/kind feature
/area core
/milestone 2.0
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#### What this PR does / why we need it:
新增插件设置，允许通过 Setting 自定义模型生成表单并收集其值为 ConfigMap
插件可以通过注入 SettingFetcher 来获取值并使用它,例如：
```java
Sns sns = settingFetcher.getGroupForObject("sns", Sns.class);
```
#### Which issue(s) this PR fixes:

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Fixes #

#### Special notes for your reviewer:
/cc @halo-dev/sig-halo 
#### Does this PR introduce a user-facing change?

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```release-note
None
```

src/main/java/run/halo/app/core/extension/Plugin.java

@@ -64,6 +64,10 @@ public class Plugin extends AbstractExtension {
         private Boolean enabled = false;
 
         private List<String> extensionLocations;
+
+        private String settingName;
+
+        private String configMapName;
     }
 
     @Getter

src/main/java/run/halo/app/core/extension/Setting.java

@@ -0,0 +1,35 @@
+package run.halo.app.core.extension;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import java.util.List;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import run.halo.app.extension.AbstractExtension;
+import run.halo.app.extension.GVK;
+
+/**
+ * {@link Setting} is a custom extension to generate forms based on configuration.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+@Data
+@EqualsAndHashCode(callSuper = true)
+@GVK(group = "", version = "v1alpha1", kind = "Setting",
+    plural = "settings", singular = "setting")
+public class Setting extends AbstractExtension {
+
+    @Schema(required = true, minLength = 1)
+    private List<SettingSpec> spec;
+
+    @Data
+    public static class SettingSpec {
+
+        @Schema(required = true)
+        private String group;
+
+        private String label;
+
+        private List<Object> formSchema;
+    }
+}

src/main/java/run/halo/app/infra/SchemeInitializer.java

@@ -8,7 +8,9 @@ import run.halo.app.core.extension.Plugin;
 import run.halo.app.core.extension.ReverseProxy;
 import run.halo.app.core.extension.Role;
 import run.halo.app.core.extension.RoleBinding;
+import run.halo.app.core.extension.Setting;
 import run.halo.app.core.extension.User;
+import run.halo.app.extension.ConfigMap;
 import run.halo.app.extension.SchemeManager;
 import run.halo.app.security.authentication.pat.PersonalAccessToken;
 
@@ -29,5 +31,7 @@ public class SchemeInitializer implements ApplicationListener<ApplicationStarted
         schemeManager.register(RoleBinding.class);
         schemeManager.register(User.class);
         schemeManager.register(ReverseProxy.class);
+        schemeManager.register(Setting.class);
+        schemeManager.register(ConfigMap.class);
     }
 }

src/main/java/run/halo/app/plugin/PluginApplicationInitializer.java

@@ -11,6 +11,7 @@ import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.lang.NonNull;
 import org.springframework.util.Assert;
 import org.springframework.util.StopWatch;
+import run.halo.app.extension.ExtensionClient;
 
 /**
  * Plugin application initializer will create plugin application context by plugin id and
@@ -65,6 +66,8 @@ public class PluginApplicationInitializer {
         AnnotationConfigUtils.registerAnnotationConfigProcessors(beanFactory);
         stopWatch.stop();
 
+        populateSettingFetcher(pluginId, beanFactory);
+
         log.debug("Total millis: {} ms -> {}", stopWatch.getTotalTimeMillis(),
             stopWatch.prettyPrint());
 
@@ -103,6 +106,14 @@ public class PluginApplicationInitializer {
             stopWatch.getTotalTimeMillis(), stopWatch.prettyPrint());
     }
 
+    private void populateSettingFetcher(String pluginName,
+        DefaultListableBeanFactory listableBeanFactory) {
+        ExtensionClient extensionClient =
+            getRootApplicationContext().getBean(ExtensionClient.class);
+        SettingFetcher settingFetcher = new SettingFetcher(pluginName, extensionClient);
+        listableBeanFactory.registerSingleton("settingFetcher", settingFetcher);
+    }
+
     public void onStartUp(String pluginId) {
         initApplicationContext(pluginId);
     }

src/main/java/run/halo/app/plugin/SettingFetcher.java

@@ -0,0 +1,93 @@
+package run.halo.app.plugin;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicReference;
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
+import run.halo.app.core.extension.Plugin;
+import run.halo.app.extension.ConfigMap;
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.infra.utils.JsonParseException;
+import run.halo.app.infra.utils.JsonUtils;
+
+/**
+ * <p>A value fetcher for pPlugin form configuration.</p>
+ * <p>The method of obtaining values is lazy,only when it is used for the first time can the real
+ * query value be obtained from {@link ConfigMap}.</p>
+ * <p>It is thread safe.</p>
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+public class SettingFetcher {
+
+    private static final String PLUGIN_SETTING_VALUE = "setting";
+
+    private final AtomicReference<JsonNode> valueRef = new AtomicReference<>(null);
+
+    private final ExtensionClient extensionClient;
+
+    private final String pluginName;
+
+    public SettingFetcher(String pluginName,
+        ExtensionClient extensionClient) {
+        this.extensionClient = extensionClient;
+        this.pluginName = pluginName;
+    }
+
+    @Nullable
+    public <T> T getGroupForObject(String group, Class<T> clazz) {
+        return convertValue(getInternal(group), clazz);
+    }
+
+    @NonNull
+    public JsonNode getGroup(String group) {
+        return getInternal(group);
+    }
+
+    @NonNull
+    public JsonNode getValues() {
+        return valueRef.updateAndGet(m -> m != null ? m : getValuesInternal());
+    }
+
+    private JsonNode getInternal(String group) {
+        return Optional.ofNullable(getValues().get(group))
+            .orElse(JsonNodeFactory.instance.missingNode());
+    }
+
+    private JsonNode getValuesInternal() {
+        return configMap(pluginName)
+            .filter(configMap -> configMap.getData() != null
+                && configMap.getData().containsKey(PLUGIN_SETTING_VALUE))
+            .map(configMap -> configMap.getData().get(PLUGIN_SETTING_VALUE))
+            .map(this::readTree)
+            .orElse(JsonNodeFactory.instance.missingNode());
+    }
+
+    private Optional<ConfigMap> configMap(String pluginName) {
+        return extensionClient.fetch(Plugin.class, pluginName)
+            .flatMap(plugin -> {
+                String configMapName = plugin.getSpec().getConfigMapName();
+                if (StringUtils.isBlank(configMapName)) {
+                    return Optional.empty();
+                }
+                return extensionClient.fetch(ConfigMap.class, plugin.getSpec().getConfigMapName());
+            });
+    }
+
+    private JsonNode readTree(String json) {
+        try {
+            return JsonUtils.DEFAULT_JSON_MAPPER.readTree(json);
+        } catch (JsonProcessingException e) {
+            throw new JsonParseException(e);
+        }
+    }
+
+    private <T> T convertValue(JsonNode jsonNode, Class<T> clazz) {
+        return JsonUtils.DEFAULT_JSON_MAPPER.convertValue(jsonNode, clazz);
+    }
+}

src/test/java/run/halo/app/core/extension/SettingTest.java

@@ -0,0 +1,104 @@
+package run.halo.app.core.extension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.List;
+import org.json.JSONException;
+import org.junit.jupiter.api.Test;
+import org.skyscreamer.jsonassert.JSONAssert;
+import org.springframework.security.util.InMemoryResource;
+import run.halo.app.extension.Unstructured;
+import run.halo.app.infra.utils.JsonUtils;
+import run.halo.app.infra.utils.YamlUnstructuredLoader;
+
+/**
+ * Tests for {@link Setting}.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+class SettingTest {
+
+    @Test
+    void setting() throws JSONException {
+        String settingYaml = """
+            apiVersion: v1alpha1
+            kind: Setting
+            metadata:
+                name: setting-name
+            spec:
+              - group: basic
+                label: 基本设置
+                formSchema:
+                  - $el: h1
+                    children: Register
+                  - $formkit: text
+                    help: This will be used for your account.
+                    label: Email
+                    name: email
+                    validation: required|email
+              - group: sns
+                label: 社交资料
+                formSchema:
+                  - $formkit: text
+                    help: This will be used for your theme.
+                    label: color
+                    name: color
+                    validation: required
+            """;
+        List<Unstructured> unstructureds =
+            new YamlUnstructuredLoader(new InMemoryResource(settingYaml)).load();
+        assertThat(unstructureds).hasSize(1);
+        Unstructured unstructured = unstructureds.get(0);
+
+        Setting setting = Unstructured.OBJECT_MAPPER.convertValue(unstructured, Setting.class);
+        assertThat(setting).isNotNull();
+        JSONAssert.assertEquals("""
+                {
+                    "spec": [
+                        {
+                            "group": "basic",
+                            "label": "基本设置",
+                            "formSchema": [
+                                {
+                                    "$el": "h1",
+                                    "children": "Register"
+                                },
+                                {
+                                    "$formkit": "text",
+                                    "help": "This will be used for your account.",
+                                    "label": "Email",
+                                    "name": "email",
+                                    "validation": "required|email"
+                                }
+                            ]
+                        },
+                        {
+                            "group": "sns",
+                            "label": "社交资料",
+                            "formSchema": [
+                                {
+                                    "$formkit": "text",
+                                    "help": "This will be used for your theme.",
+                                    "label": "color",
+                                    "name": "color",
+                                    "validation": "required"
+                                }
+                            ]
+                        }
+                    ],
+                    "apiVersion": "v1alpha1",
+                    "kind": "Setting",
+                    "metadata": {
+                        "name": "setting-name",
+                        "labels": null,
+                        "annotations": null,
+                        "version": null,
+                        "creationTimestamp": null,
+                        "deletionTimestamp": null
+                    }
+                }
+                """,
+            JsonUtils.objectToJson(setting), false);
+    }
+}

src/test/java/run/halo/app/plugin/SettingFetcherTest.java

@@ -0,0 +1,148 @@
+package run.halo.app.plugin;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import org.json.JSONException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.skyscreamer.jsonassert.JSONAssert;
+import run.halo.app.core.extension.Plugin;
+import run.halo.app.extension.ConfigMap;
+import run.halo.app.extension.ExtensionClient;
+import run.halo.app.extension.Metadata;
+import run.halo.app.infra.utils.JsonUtils;
+
+/**
+ * Tests for {@link SettingFetcher}.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+@ExtendWith(MockitoExtension.class)
+class SettingFetcherTest {
+
+    @Mock
+    private ExtensionClient extensionClient;
+
+    private SettingFetcher settingFetcher;
+
+    @BeforeEach
+    void setUp() {
+        settingFetcher = new SettingFetcher("fake", extensionClient);
+        // do not call extensionClient when the settingFetcher first time created
+        verify(extensionClient, times(0)).fetch(eq(ConfigMap.class), any());
+        verify(extensionClient, times(0)).fetch(eq(Plugin.class), any());
+
+        Plugin plugin = buildPlugin();
+        when(extensionClient.fetch(eq(Plugin.class), any())).thenReturn(Optional.of(plugin));
+
+        ConfigMap configMap = buildConfigMap();
+        when(extensionClient.fetch(eq(ConfigMap.class), any())).thenReturn(Optional.of(configMap));
+    }
+
+    @Test
+    void getValues() throws JSONException {
+        JsonNode values = settingFetcher.getValues();
+
+        verify(extensionClient, times(1)).fetch(eq(ConfigMap.class), any());
+
+        assertThat(values).hasSize(2);
+        JSONAssert.assertEquals(getSns(), JsonUtils.objectToJson(values.get("sns")), true);
+
+        // The extensionClient will only be called once
+        JsonNode callAgain = settingFetcher.getValues();
+        assertThat(callAgain).isNotNull();
+        verify(extensionClient, times(1)).fetch(eq(ConfigMap.class), any());
+    }
+
+    @Test
+    void getGroupForObject() throws JSONException {
+        Sns sns = settingFetcher.getGroupForObject("sns", Sns.class);
+        assertThat(sns).isNotNull();
+        JSONAssert.assertEquals(getSns(), JsonUtils.objectToJson(sns), true);
+
+        Sns missing = settingFetcher.getGroupForObject("sns1", Sns.class);
+        assertThat(missing).isNull();
+    }
+
+    @Test
+    void getGroup() {
+        JsonNode jsonNode = settingFetcher.getGroup("basic");
+        assertThat(jsonNode).isNotNull();
+        assertThat(jsonNode.isObject()).isTrue();
+        assertThat(jsonNode.get("color").asText()).isEqualTo("red");
+        assertThat(jsonNode.get("width").asInt()).isEqualTo(100);
+
+        // missing key will return empty json node
+        JsonNode emptyNode = settingFetcher.getGroup("basic1");
+        assertThat(emptyNode.isEmpty()).isTrue();
+    }
+
+    private ConfigMap buildConfigMap() {
+        ConfigMap configMap = new ConfigMap();
+        Metadata metadata = new Metadata();
+        metadata.setName("fake");
+        metadata.setLabels(Map.of("plugin.halo.run/plugin-name", "fake"));
+        configMap.setMetadata(metadata);
+        configMap.setKind("ConfigMap");
+        configMap.setApiVersion("v1alpha1");
+        configMap.setData(Map.of("setting", String.format("""
+            {
+                 "sns": %s,
+                 "basic": {
+                     "color": "red",
+                     "width": "100"
+                 }
+            }
+            """, getSns())));
+        return configMap;
+    }
+
+    private Plugin buildPlugin() {
+        Plugin plugin = new Plugin();
+        plugin.setKind("Plugin");
+        plugin.setApiVersion("plugin.halo.run/v1alpha1");
+
+        Metadata pluginMetadata = new Metadata();
+        pluginMetadata.setName("fakePlugin");
+        plugin.setMetadata(pluginMetadata);
+
+        Plugin.PluginSpec pluginSpec = new Plugin.PluginSpec();
+        pluginSpec.setConfigMapName("fakeConfigMap");
+        pluginSpec.setSettingName("fakeSetting");
+        plugin.setSpec(pluginSpec);
+        return plugin;
+    }
+
+    String getSns() {
+        return """
+            {
+                "email": "example@example.com",
+                "github": "example",
+                "instagram": "123",
+                "twitter": "halo-dev",
+                "user": {
+                "name": "guqing",
+                "age": "18"
+                },
+                "nums": [1, 2, 3]
+            }
+            """;
+    }
+
+    record Sns(String email, String github, String instagram, String twitter,
+               Map<String, Object> user, List<Integer> nums) {
+    }
+}

src/test/java/run/halo/app/plugin/YamlPluginFinderTest.java

@@ -94,7 +94,9 @@ class YamlPluginFinderTest {
                         "requires": ">=2.0.0",
                         "pluginClass": "run.halo.app.plugin.BasePlugin",
                         "enabled": false,
-                        "extensionLocations": null
+                        "extensionLocations": null,
+                        settingName: null,
+                        configMapName: null
                     },
                     "status": null,
                     "apiVersion": "plugin.halo.run/v1alpha1",