Add Get QueryGroup API Logic

Signed-off-by: Ruirui Zhang <mariazrr@amazon.com>

plugins/workload-management/build.gradle

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+
+opensearchplugin {
+  description 'OpenSearch Workload Management Plugin.'
+  classname 'org.opensearch.plugin.wlm.action.WorkloadManagementPlugin'
+}
+
+dependencies {
+}

plugins/workload-management/src/main/java/org/opensearch/plugin/wlm/action/GetQueryGroupAction.java

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugin.wlm.action;
+
+import org.opensearch.action.ActionType;
+
+/**
+ * Transport action to get QueryGroup
+ *
+ * @opensearch.api
+ */
+public class GetQueryGroupAction extends ActionType<GetQueryGroupResponse> {
+
+    /**
+     /**
+     * An instance of GetQueryGroupAction
+     */
+    public static final GetQueryGroupAction INSTANCE = new GetQueryGroupAction();
+
+    /**
+     * Name for GetQueryGroupAction
+     */
+    public static final String NAME = "cluster:admin/opensearch/query_group/wlm/_get";
+
+    /**
+     * Default constructor
+     */
+    private GetQueryGroupAction() {
+        super(NAME, GetQueryGroupResponse::new);
+    }
+}

plugins/workload-management/src/main/java/org/opensearch/plugin/wlm/action/GetQueryGroupRequest.java

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugin.wlm.action;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.action.ActionRequestValidationException;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.common.io.stream.Writeable;
+
+import java.io.IOException;
+
+/**
+ * A request for get QueryGroup
+ *
+ * @opensearch.internal
+ */
+public class GetQueryGroupRequest extends ActionRequest implements Writeable.Reader<GetQueryGroupRequest> {
+    String name;
+
+    /**
+     * Default constructor for GetQueryGroupRequest
+     * @param name - name for the QueryGroup to get
+     */
+    public GetQueryGroupRequest(String name) {
+        this.name = name;
+    }
+
+    /**
+     * Constructor for GetQueryGroupRequest
+     * @param in - A {@link StreamInput} object
+     */
+    public GetQueryGroupRequest(StreamInput in) throws IOException {
+        super(in);
+        name = in.readOptionalString();
+    }
+
+    @Override
+    public GetQueryGroupRequest read(StreamInput in) throws IOException {
+        return new GetQueryGroupRequest(in);
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+
+    /**
+     * Name getter
+     */
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeOptionalString(name);
+    }
+}

plugins/workload-management/src/main/java/org/opensearch/plugin/wlm/action/GetQueryGroupResponse.java

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugin.wlm.action;
+
+import org.opensearch.cluster.metadata.QueryGroup;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.core.common.io.stream.StreamInput;
+import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.ToXContentObject;
+import org.opensearch.core.xcontent.XContentBuilder;
+
+import java.io.IOException;
+import java.util.List;
+
+/**
+ * Response for the get API for QueryGroup
+ *
+ * @opensearch.internal
+ */
+public class GetQueryGroupResponse extends ActionResponse implements ToXContent, ToXContentObject {
+    private final List<QueryGroup> queryGroups;
+    private RestStatus restStatus;
+
+    /**
+     * Constructor for GetQueryGroupResponse
+     * @param queryGroups - The QueryGroup list to be fetched
+     * @param restStatus - The rest status of the request
+     */
+    public GetQueryGroupResponse(final List<QueryGroup> queryGroups, RestStatus restStatus) {
+        this.queryGroups = queryGroups;
+        this.restStatus = restStatus;
+    }
+
+    /**
+     * Constructor for GetQueryGroupResponse
+     * @param in - A {@link StreamInput} object
+     */
+    public GetQueryGroupResponse(StreamInput in) throws IOException {
+        this.queryGroups = in.readList(QueryGroup::new);
+        restStatus = RestStatus.readFrom(in);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeList(queryGroups);
+        RestStatus.writeTo(out, restStatus);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject();
+        builder.startArray("query_groups");
+        for (QueryGroup group : queryGroups) {
+            group.toXContent(builder, params);
+        }
+        builder.endArray();
+        builder.endObject();
+        return builder;
+    }
+
+    /**
+     * queryGroups getter
+     */
+    public List<QueryGroup> getQueryGroups() {
+        return queryGroups;
+    }
+
+    /**
+     * restStatus getter
+     */
+    public RestStatus getRestStatus() {
+        return restStatus;
+    }
+}

plugins/workload-management/src/main/java/org/opensearch/plugin/wlm/action/TransportGetQueryGroupAction.java

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugin.wlm.action;
+
+import org.opensearch.action.support.ActionFilters;
+import org.opensearch.action.support.HandledTransportAction;
+import org.opensearch.cluster.metadata.QueryGroup;
+import org.opensearch.common.inject.Inject;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.plugin.wlm.action.service.Persistable;
+import org.opensearch.tasks.Task;
+import org.opensearch.threadpool.ThreadPool;
+import org.opensearch.transport.TransportService;
+
+/**
+ * Transport action for get QueryGroup
+ *
+ * @opensearch.internal
+ */
+public class TransportGetQueryGroupAction extends HandledTransportAction<GetQueryGroupRequest, GetQueryGroupResponse> {
+
+    private final ThreadPool threadPool;
+    private final Persistable<QueryGroup> queryGroupPersistenceService;
+
+    /**
+     * Constructor for TransportGetQueryGroupAction
+     *
+     * @param actionName - action name
+     * @param transportService - a {@link TransportService} object
+     * @param actionFilters - a {@link ActionFilters} object
+     * @param threadPool - a {@link ThreadPool} object
+     * @param queryGroupPersistenceService - a {@link Persistable} object
+     */
+    @Inject
+    public TransportGetQueryGroupAction(
+        String actionName,
+        TransportService transportService,
+        ActionFilters actionFilters,
+        ThreadPool threadPool,
+        Persistable<QueryGroup> queryGroupPersistenceService
+    ) {
+        super(GetQueryGroupAction.NAME, transportService, actionFilters, GetQueryGroupRequest::new);
+        this.threadPool = threadPool;
+        this.queryGroupPersistenceService = queryGroupPersistenceService;
+    }
+
+    @Override
+    protected void doExecute(Task task, GetQueryGroupRequest request, ActionListener<GetQueryGroupResponse> listener) {
+        String name = request.getName();
+        threadPool.executor(ThreadPool.Names.GENERIC).execute(() -> queryGroupPersistenceService.get(name, listener));
+    }
+}

plugins/workload-management/src/main/java/org/opensearch/plugin/wlm/action/WorkloadManagementPlugin.java

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugin.wlm.action;
+
+import org.opensearch.action.ActionRequest;
+import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
+import org.opensearch.cluster.node.DiscoveryNodes;
+import org.opensearch.common.inject.Module;
+import org.opensearch.common.settings.ClusterSettings;
+import org.opensearch.common.settings.IndexScopedSettings;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.settings.SettingsFilter;
+import org.opensearch.core.action.ActionResponse;
+import org.opensearch.plugin.wlm.action.rest.RestGetQueryGroupAction;
+import org.opensearch.plugins.ActionPlugin;
+import org.opensearch.plugins.Plugin;
+import org.opensearch.rest.RestController;
+import org.opensearch.rest.RestHandler;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.function.Supplier;
+
+/**
+ * Plugin class for WorkloadManagement
+ */
+public class WorkloadManagementPlugin extends Plugin implements ActionPlugin {
+
+    /**
+     * Default constructor
+     */
+    public WorkloadManagementPlugin() {}
+
+    @Override
+    public List<ActionHandler<? extends ActionRequest, ? extends ActionResponse>> getActions() {
+        return List.of(new ActionPlugin.ActionHandler<>(GetQueryGroupAction.INSTANCE, TransportGetQueryGroupAction.class));
+    }
+
+    @Override
+    public List<RestHandler> getRestHandlers(
+        Settings settings,
+        RestController restController,
+        ClusterSettings clusterSettings,
+        IndexScopedSettings indexScopedSettings,
+        SettingsFilter settingsFilter,
+        IndexNameExpressionResolver indexNameExpressionResolver,
+        Supplier<DiscoveryNodes> nodesInCluster
+    ) {
+        return List.of(new RestGetQueryGroupAction());
+    }
+
+    @Override
+    public Collection<Module> createGuiceModules() {
+        return List.of(new WorkloadManagementPluginModule());
+    }
+}

plugins/workload-management/src/main/java/org/opensearch/plugin/wlm/action/WorkloadManagementPluginModule.java

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugin.wlm.action;
+
+import org.opensearch.cluster.metadata.QueryGroup;
+import org.opensearch.common.inject.AbstractModule;
+import org.opensearch.common.inject.TypeLiteral;
+import org.opensearch.plugin.wlm.action.service.Persistable;
+import org.opensearch.plugin.wlm.action.service.QueryGroupPersistenceService;
+
+/**
+ * Guice Module to manage WorkloadManagement related objects
+ */
+public class WorkloadManagementPluginModule extends AbstractModule {
+
+    /**
+     * Constructor for WorkloadManagementPluginModule
+     */
+    public WorkloadManagementPluginModule() {}
+
+    @Override
+    protected void configure() {
+        bind(new TypeLiteral<Persistable<QueryGroup>>() {
+        }).to(QueryGroupPersistenceService.class).asEagerSingleton();
+    }
+}

plugins/workload-management/src/main/java/org/opensearch/plugin/wlm/action/package-info.java

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+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+/**
+ * Base Package of CRUD API of QueryGroup
+ */
+package org.opensearch.plugin.wlm.action;