Add Get Workflow API to retrieve a stored template by workflow id

src/main/java/org/opensearch/flowframework/FlowFrameworkPlugin.java

@@ -29,11 +29,14 @@
 import org.opensearch.flowframework.indices.FlowFrameworkIndicesHandler;
 import org.opensearch.flowframework.rest.RestCreateWorkflowAction;
 import org.opensearch.flowframework.rest.RestGetWorkflowAction;
+import org.opensearch.flowframework.rest.RestGetWorkflowStateAction;
 import org.opensearch.flowframework.rest.RestProvisionWorkflowAction;
 import org.opensearch.flowframework.rest.RestSearchWorkflowAction;
 import org.opensearch.flowframework.transport.CreateWorkflowAction;
 import org.opensearch.flowframework.transport.CreateWorkflowTransportAction;
 import org.opensearch.flowframework.transport.GetWorkflowAction;
+import org.opensearch.flowframework.transport.GetWorkflowStateAction;
+import org.opensearch.flowframework.transport.GetWorkflowStateTransportAction;
 import org.opensearch.flowframework.transport.GetWorkflowTransportAction;
 import org.opensearch.flowframework.transport.ProvisionWorkflowAction;
 import org.opensearch.flowframework.transport.ProvisionWorkflowTransportAction;
@@ -125,6 +128,7 @@ public List<RestHandler> getRestHandlers(
             new RestCreateWorkflowAction(flowFrameworkFeatureEnabledSetting, settings, clusterService),
             new RestProvisionWorkflowAction(flowFrameworkFeatureEnabledSetting),
             new RestSearchWorkflowAction(flowFrameworkFeatureEnabledSetting),
+            new RestGetWorkflowStateAction(flowFrameworkFeatureEnabledSetting),
             new RestGetWorkflowAction(flowFrameworkFeatureEnabledSetting)
         );
     }
@@ -135,6 +139,7 @@ public List<RestHandler> getRestHandlers(
             new ActionHandler<>(CreateWorkflowAction.INSTANCE, CreateWorkflowTransportAction.class),
             new ActionHandler<>(ProvisionWorkflowAction.INSTANCE, ProvisionWorkflowTransportAction.class),
             new ActionHandler<>(SearchWorkflowAction.INSTANCE, SearchWorkflowTransportAction.class),
+            new ActionHandler<>(GetWorkflowStateAction.INSTANCE, GetWorkflowStateTransportAction.class),
             new ActionHandler<>(GetWorkflowAction.INSTANCE, GetWorkflowTransportAction.class)
         );
     }

src/main/java/org/opensearch/flowframework/rest/RestGetWorkflowAction.java

@@ -20,7 +20,7 @@
 import org.opensearch.flowframework.common.FlowFrameworkFeatureEnabledSetting;
 import org.opensearch.flowframework.exception.FlowFrameworkException;
 import org.opensearch.flowframework.transport.GetWorkflowAction;
-import org.opensearch.flowframework.transport.GetWorkflowRequest;
+import org.opensearch.flowframework.transport.WorkflowRequest;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.rest.BytesRestResponse;
 import org.opensearch.rest.RestRequest;
@@ -34,7 +34,7 @@
 import static org.opensearch.flowframework.common.FlowFrameworkSettings.FLOW_FRAMEWORK_ENABLED;
 
 /**
- * Rest Action to facilitate requests to get a workflow status
+ * Rest Action to facilitate requests to get a stored template
  */
 public class RestGetWorkflowAction extends BaseRestHandler {
 
@@ -55,6 +55,11 @@ public String getName() {
         return GET_WORKFLOW_ACTION;
     }
 
+    @Override
+    public List<Route> routes() {
+        return ImmutableList.of(new Route(RestRequest.Method.GET, String.format(Locale.ROOT, "%s/{%s}", WORKFLOW_URI, WORKFLOW_ID)));
+    }
+
     @Override
     protected BaseRestHandler.RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
 
@@ -68,17 +73,16 @@ protected BaseRestHandler.RestChannelConsumer prepareRequest(RestRequest request
 
             // Validate content
             if (request.hasContent()) {
-                throw new FlowFrameworkException("No request body present", RestStatus.BAD_REQUEST);
+                throw new FlowFrameworkException("Invalid request format", RestStatus.BAD_REQUEST);
             }
             // Validate params
             String workflowId = request.param(WORKFLOW_ID);
             if (workflowId == null) {
                 throw new FlowFrameworkException("workflow_id cannot be null", RestStatus.BAD_REQUEST);
             }
 
-            boolean all = request.paramAsBoolean("all", false);
-            GetWorkflowRequest getWorkflowRequest = new GetWorkflowRequest(workflowId, all);
-            return channel -> client.execute(GetWorkflowAction.INSTANCE, getWorkflowRequest, ActionListener.wrap(response -> {
+            WorkflowRequest workflowRequest = new WorkflowRequest(workflowId, null);
+            return channel -> client.execute(GetWorkflowAction.INSTANCE, workflowRequest, ActionListener.wrap(response -> {
                 XContentBuilder builder = response.toXContent(channel.newBuilder(), ToXContent.EMPTY_PARAMS);
                 channel.sendResponse(new BytesRestResponse(RestStatus.OK, builder));
             }, exception -> {
@@ -88,7 +92,7 @@ protected BaseRestHandler.RestChannelConsumer prepareRequest(RestRequest request
                     channel.sendResponse(new BytesRestResponse(ex.getRestStatus(), exceptionBuilder));
 
                 } catch (IOException e) {
-                    logger.error("Failed to send back provision workflow exception", e);
+                    logger.error("Failed to send back get template exception", e);
                     channel.sendResponse(new BytesRestResponse(ExceptionsHelper.status(e), e.getMessage()));
                 }
             }));
@@ -99,12 +103,4 @@ protected BaseRestHandler.RestChannelConsumer prepareRequest(RestRequest request
             );
         }
     }
-
-    @Override
-    public List<Route> routes() {
-        return ImmutableList.of(
-            // Provision workflow from indexed use case template
-            new Route(RestRequest.Method.GET, String.format(Locale.ROOT, "%s/{%s}/%s", WORKFLOW_URI, WORKFLOW_ID, "_status"))
-        );
-    }
 }

src/main/java/org/opensearch/flowframework/rest/RestGetWorkflowStateAction.java

@@ -0,0 +1,109 @@
+/*
+ * Copyright OpenSearch Contributors
+ * 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.flowframework.rest;
+
+import com.google.common.collect.ImmutableList;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.ExceptionsHelper;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.core.action.ActionListener;
+import org.opensearch.core.rest.RestStatus;
+import org.opensearch.core.xcontent.ToXContent;
+import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.flowframework.common.FlowFrameworkFeatureEnabledSetting;
+import org.opensearch.flowframework.exception.FlowFrameworkException;
+import org.opensearch.flowframework.transport.GetWorkflowStateAction;
+import org.opensearch.flowframework.transport.GetWorkflowStateRequest;
+import org.opensearch.rest.BaseRestHandler;
+import org.opensearch.rest.BytesRestResponse;
+import org.opensearch.rest.RestRequest;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Locale;
+
+import static org.opensearch.flowframework.common.CommonValue.WORKFLOW_ID;
+import static org.opensearch.flowframework.common.CommonValue.WORKFLOW_URI;
+import static org.opensearch.flowframework.common.FlowFrameworkSettings.FLOW_FRAMEWORK_ENABLED;
+
+/**
+ * Rest Action to facilitate requests to get a workflow status
+ */
+public class RestGetWorkflowStateAction extends BaseRestHandler {
+
+    private static final String GET_WORKFLOW_STATE_ACTION = "get_workflow_state";
+    private static final Logger logger = LogManager.getLogger(RestGetWorkflowStateAction.class);
+    private FlowFrameworkFeatureEnabledSetting flowFrameworkFeatureEnabledSetting;
+
+    /**
+     * Instantiates a new RestGetWorkflowStateAction
+     * @param flowFrameworkFeatureEnabledSetting Whether this API is enabled
+     */
+    public RestGetWorkflowStateAction(FlowFrameworkFeatureEnabledSetting flowFrameworkFeatureEnabledSetting) {
+        this.flowFrameworkFeatureEnabledSetting = flowFrameworkFeatureEnabledSetting;
+    }
+
+    @Override
+    public String getName() {
+        return GET_WORKFLOW_STATE_ACTION;
+    }
+
+    @Override
+    protected BaseRestHandler.RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
+
+        try {
+            if (!flowFrameworkFeatureEnabledSetting.isFlowFrameworkEnabled()) {
+                throw new FlowFrameworkException(
+                    "This API is disabled. To enable it, update the setting [" + FLOW_FRAMEWORK_ENABLED.getKey() + "] to true.",
+                    RestStatus.FORBIDDEN
+                );
+            }
+
+            // Validate content
+            if (request.hasContent()) {
+                throw new FlowFrameworkException("No request body present", RestStatus.BAD_REQUEST);
+            }
+            // Validate params
+            String workflowId = request.param(WORKFLOW_ID);
+            if (workflowId == null) {
+                throw new FlowFrameworkException("workflow_id cannot be null", RestStatus.BAD_REQUEST);
+            }
+
+            boolean all = request.paramAsBoolean("all", false);
+            GetWorkflowStateRequest getWorkflowRequest = new GetWorkflowStateRequest(workflowId, all);
+            return channel -> client.execute(GetWorkflowStateAction.INSTANCE, getWorkflowRequest, ActionListener.wrap(response -> {
+                XContentBuilder builder = response.toXContent(channel.newBuilder(), ToXContent.EMPTY_PARAMS);
+                channel.sendResponse(new BytesRestResponse(RestStatus.OK, builder));
+            }, exception -> {
+                try {
+                    FlowFrameworkException ex = new FlowFrameworkException(exception.getMessage(), ExceptionsHelper.status(exception));
+                    XContentBuilder exceptionBuilder = ex.toXContent(channel.newErrorBuilder(), ToXContent.EMPTY_PARAMS);
+                    channel.sendResponse(new BytesRestResponse(ex.getRestStatus(), exceptionBuilder));
+
+                } catch (IOException e) {
+                    logger.error("Failed to send back provision workflow exception", e);
+                    channel.sendResponse(new BytesRestResponse(ExceptionsHelper.status(e), e.getMessage()));
+                }
+            }));
+
+        } catch (FlowFrameworkException ex) {
+            return channel -> channel.sendResponse(
+                new BytesRestResponse(ex.getRestStatus(), ex.toXContent(channel.newErrorBuilder(), ToXContent.EMPTY_PARAMS))
+            );
+        }
+    }
+
+    @Override
+    public List<Route> routes() {
+        return ImmutableList.of(
+            new Route(RestRequest.Method.GET, String.format(Locale.ROOT, "%s/{%s}/%s", WORKFLOW_URI, WORKFLOW_ID, "_status"))
+        );
+    }
+}

src/main/java/org/opensearch/flowframework/transport/GetWorkflowResponse.java

@@ -13,55 +13,52 @@
 import org.opensearch.core.common.io.stream.StreamOutput;
 import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.core.xcontent.XContentBuilder;
-import org.opensearch.flowframework.model.WorkflowState;
+import org.opensearch.flowframework.model.Template;
 
 import java.io.IOException;
 
 /**
- * Transport Response from getting a workflow status
+ * Transport Response from getting a template
  */
 public class GetWorkflowResponse extends ActionResponse implements ToXContentObject {
 
-    /** The workflow state */
-    public WorkflowState workflowState;
-    /** Flag to indicate if the entire state should be returned */
-    public boolean allStatus;
+    /** The template */
+    private Template template;
 
     /**
      * Instantiates a new GetWorkflowResponse from an input stream
      * @param in the input stream to read from
-     * @throws IOException if the workflowId cannot be read from the input stream
+     * @throws IOException if the template json cannot be read from the input stream
      */
     public GetWorkflowResponse(StreamInput in) throws IOException {
         super(in);
-        workflowState = new WorkflowState(in);
-        allStatus = in.readBoolean();
+        this.template = Template.parse(in.readString());
     }
 
     /**
-     * Instatiates a new GetWorkflowResponse from an input stream
-     * @param workflowState the workflow state object
-     * @param allStatus whether to return all fields in state index
+     * Instantiates a new GetWorkflowResponse
+     * @param template the template
      */
-    public GetWorkflowResponse(WorkflowState workflowState, boolean allStatus) {
-        if (allStatus) {
-            this.workflowState = workflowState;
-        } else {
-            this.workflowState = new WorkflowState.Builder().workflowId(workflowState.getWorkflowId())
-                .error(workflowState.getError())
-                .state(workflowState.getState())
-                .resourcesCreated(workflowState.resourcesCreated())
-                .build();
-        }
+    public GetWorkflowResponse(Template template) {
+        this.template = template;
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        workflowState.writeTo(out);
+        out.writeString(template.toJson());
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder xContentBuilder, Params params) throws IOException {
-        return workflowState.toXContent(xContentBuilder, params);
+        return this.template.toXContent(xContentBuilder, params);
     }
+
+    /**
+     * Gets the template
+     * @return the template
+     */
+    public Template getTemplate() {
+        return this.template;
+    }
+
 }

src/main/java/org/opensearch/flowframework/transport/GetWorkflowStateAction.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright OpenSearch Contributors
+ * 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.flowframework.transport;
+
+import org.opensearch.action.ActionType;
+
+import static org.opensearch.flowframework.common.CommonValue.TRANSPORT_ACTION_NAME_PREFIX;
+
+/**
+ * External Action for public facing RestGetWorkflowStateAction
+ */
+public class GetWorkflowStateAction extends ActionType<GetWorkflowStateResponse> {
+    /** The name of this action */
+    public static final String NAME = TRANSPORT_ACTION_NAME_PREFIX + "workflowstate/get";
+    /** An instance of this action */
+    public static final GetWorkflowStateAction INSTANCE = new GetWorkflowStateAction();
+
+    private GetWorkflowStateAction() {
+        super(NAME, GetWorkflowStateResponse::new);
+    }
+}

src/main/java/org/opensearch/flowframework/transport/GetWorkflowRequest.java → src/main/java/org/opensearch/flowframework/transport/GetWorkflowStateRequest.java

@@ -17,9 +17,9 @@
 import java.io.IOException;
 
 /**
- * Transport Request to get a workflow or workflow status
+ * Transport Request to get a workflow state
  */
-public class GetWorkflowRequest extends ActionRequest {
+public class GetWorkflowStateRequest extends ActionRequest {
 
     /**
      * The documentId of the workflow entry within the Global Context index
@@ -37,7 +37,7 @@ public class GetWorkflowRequest extends ActionRequest {
      * @param workflowId the documentId of the workflow
      * @param all whether the get request is looking for all fields in status
      */
-    public GetWorkflowRequest(@Nullable String workflowId, boolean all) {
+    public GetWorkflowStateRequest(@Nullable String workflowId, boolean all) {
         this.workflowId = workflowId;
         this.all = all;
     }
@@ -47,7 +47,7 @@ public GetWorkflowRequest(@Nullable String workflowId, boolean all) {
      * @param in The input stream to read from
      * @throws IOException If the stream cannot be read properly
      */
-    public GetWorkflowRequest(StreamInput in) throws IOException {
+    public GetWorkflowStateRequest(StreamInput in) throws IOException {
         super(in);
         this.workflowId = in.readString();
         this.all = in.readBoolean();