[Backport 2.x] Add WorkflowStep Factory and implement XContent-based Template Parsing

build.gradle

@@ -106,7 +106,6 @@ repositories {
 dependencies {
     implementation "org.opensearch:opensearch:${opensearch_version}"
     implementation 'org.junit.jupiter:junit-jupiter:5.10.0'
-    implementation "com.google.code.gson:gson:2.10.1"
     implementation "com.google.guava:guava:32.1.2-jre"
     api group: 'org.opensearch', name:'opensearch-ml-client', version: "${opensearch_build}"
 

src/main/java/demo/Demo.java

@@ -10,48 +10,41 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.opensearch.client.Client;
+import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.io.PathUtils;
-import org.opensearch.flowframework.template.ProcessNode;
-import org.opensearch.flowframework.template.TemplateParser;
-import org.opensearch.flowframework.workflow.WorkflowStep;
+import org.opensearch.flowframework.model.Template;
+import org.opensearch.flowframework.workflow.ProcessNode;
+import org.opensearch.flowframework.workflow.WorkflowProcessSorter;
+import org.opensearch.flowframework.workflow.WorkflowStepFactory;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
-import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.stream.Collectors;
 
 /**
- * Demo class exercising {@link TemplateParser}. This will be moved to a unit test.
+ * Demo class exercising {@link WorkflowProcessSorter}. This will be moved to a unit test.
  */
 public class Demo {
 
     private static final Logger logger = LogManager.getLogger(Demo.class);
 
-    // This is temporary. We need a factory class to generate these workflow steps
-    // based on a field in the JSON.
-    private static Map<String, WorkflowStep> workflowMap = new HashMap<>();
-    static {
-        workflowMap.put("fetch_model", new DemoWorkflowStep(3000));
-        workflowMap.put("create_ingest_pipeline", new DemoWorkflowStep(3000));
-        workflowMap.put("create_search_pipeline", new DemoWorkflowStep(5000));
-        workflowMap.put("create_neural_search_index", new DemoWorkflowStep(2000));
-    }
-
     /**
      * Demonstrate parsing a JSON graph.
      *
      * @param args unused
+     * @throws IOException on a failure
      */
     @SuppressForbidden(reason = "just a demo class that will be deleted")
-    public static void main(String[] args) {
+    public static void main(String[] args) throws IOException {
         String path = "src/test/resources/template/demo.json";
         String json;
         try {
@@ -60,13 +53,18 @@ public static void main(String[] args) {
             logger.error("Failed to read JSON at path {}", path);
             return;
         }
+        Client client = new NodeClient(null, null);
+        WorkflowStepFactory factory = WorkflowStepFactory.create(client);
+        ExecutorService executor = Executors.newFixedThreadPool(10);
+        WorkflowProcessSorter.create(factory, executor);
 
         logger.info("Parsing graph to sequence...");
-        List<ProcessNode> processSequence = TemplateParser.parseJsonGraphToSequence(json, workflowMap);
+        Template t = Template.parse(json);
+        List<ProcessNode> processSequence = WorkflowProcessSorter.get().sortProcessNodes(t.workflows().get("demo"));
         List<CompletableFuture<?>> futureList = new ArrayList<>();
 
         for (ProcessNode n : processSequence) {
-            Set<ProcessNode> predecessors = n.getPredecessors();
+            List<ProcessNode> predecessors = n.predecessors();
             logger.info(
                 "Queueing process [{}].{}",
                 n.id(),
@@ -78,11 +76,10 @@ public static void main(String[] args) {
                         predecessors.stream().map(p -> p.id()).collect(Collectors.joining(", "))
                     )
             );
-            // TODO need to handle this better, passing an argument when we start them all at the beginning is silly
             futureList.add(n.execute());
         }
         futureList.forEach(CompletableFuture::join);
         logger.info("All done!");
+        executor.shutdown();
     }
-
 }

src/main/java/demo/TemplateParseDemo.java

@@ -0,0 +1,65 @@
+/*
+ * 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 demo;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.opensearch.client.Client;
+import org.opensearch.client.node.NodeClient;
+import org.opensearch.common.SuppressForbidden;
+import org.opensearch.common.io.PathUtils;
+import org.opensearch.flowframework.model.Template;
+import org.opensearch.flowframework.model.Workflow;
+import org.opensearch.flowframework.workflow.WorkflowProcessSorter;
+import org.opensearch.flowframework.workflow.WorkflowStepFactory;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.util.Map.Entry;
+import java.util.concurrent.Executors;
+
+/**
+ * Demo class exercising {@link WorkflowProcessSorter}. This will be moved to a unit test.
+ */
+public class TemplateParseDemo {
+
+    private static final Logger logger = LogManager.getLogger(TemplateParseDemo.class);
+
+    /**
+     * Demonstrate parsing a JSON graph.
+     *
+     * @param args unused
+     * @throws IOException on error.
+     */
+    @SuppressForbidden(reason = "just a demo class that will be deleted")
+    public static void main(String[] args) throws IOException {
+        String path = "src/test/resources/template/finaltemplate.json";
+        String json;
+        try {
+            json = new String(Files.readAllBytes(PathUtils.get(path)), StandardCharsets.UTF_8);
+        } catch (IOException e) {
+            logger.error("Failed to read JSON at path {}", path);
+            return;
+        }
+        Client client = new NodeClient(null, null);
+        WorkflowStepFactory factory = WorkflowStepFactory.create(client);
+        WorkflowProcessSorter.create(factory, Executors.newFixedThreadPool(10));
+
+        Template t = Template.parse(json);
+
+        System.out.println(t.toJson());
+        System.out.println(t.toYaml());
+
+        for (Entry<String, Workflow> e : t.workflows().entrySet()) {
+            logger.info("Parsing {} workflow.", e.getKey());
+            WorkflowProcessSorter.get().sortProcessNodes(e.getValue());
+        }
+    }
+}

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

@@ -16,8 +16,8 @@
 import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.env.Environment;
 import org.opensearch.env.NodeEnvironment;
-import org.opensearch.flowframework.workflow.CreateIndex.CreateIndexStep;
-import org.opensearch.flowframework.workflow.CreateIngestPipelineStep;
+import org.opensearch.flowframework.workflow.WorkflowProcessSorter;
+import org.opensearch.flowframework.workflow.WorkflowStepFactory;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.script.ScriptService;
@@ -32,8 +32,6 @@
  */
 public class FlowFrameworkPlugin extends Plugin {
 
-    private Client client;
-
     @Override
     public Collection<Object> createComponents(
         Client client,
@@ -48,9 +46,9 @@
         IndexNameExpressionResolver indexNameExpressionResolver,
         Supplier<RepositoriesService> repositoriesServiceSupplier
     ) {
-        this.client = client;
-        CreateIngestPipelineStep createIngestPipelineStep = new CreateIngestPipelineStep(client);
-        CreateIndexStep createIndexStep = new CreateIndexStep(client);
-        return ImmutableList.of(createIngestPipelineStep, createIndexStep);
+        WorkflowStepFactory workflowStepFactory = WorkflowStepFactory.create(client);
+        WorkflowProcessSorter workflowProcessSorter = WorkflowProcessSorter.create(workflowStepFactory, threadPool.generic());
+
+        return ImmutableList.of(workflowStepFactory, workflowProcessSorter);
     }
 }