Add Data Flow Load Generator Example

The `dataflow-template-load-generator` will be able to create a parameterized amount of task applications and generate a definable amount of task/batch executions.

dataflow-template-load-generator/src/main/java/org/springframework/cloud/samples/dataflowtemplate/LoadGeneratorApplication.java

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+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.samples.dataflowtemplate;
+
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.ApplicationArguments;
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.dataflow.rest.client.DataFlowTemplate;
+import org.springframework.cloud.dataflow.rest.client.TaskOperations;
+import org.springframework.cloud.dataflow.rest.client.config.DataFlowClientAutoConfiguration;
+import org.springframework.cloud.dataflow.rest.resource.AppRegistrationResource;
+import org.springframework.cloud.dataflow.rest.resource.CurrentTaskExecutionsResource;
+import org.springframework.cloud.dataflow.rest.resource.TaskDefinitionResource;
+import org.springframework.cloud.dataflow.rest.util.HttpClientConfigurer;
+import org.springframework.hateoas.PagedResources;
+import org.springframework.web.client.RestTemplate;
+
+/**
+ *
+ * @author Gunnar Hillert
+ *
+ */
+@SpringBootApplication(exclude = { DataFlowClientAutoConfiguration.class })
+public class LoadGeneratorApplication implements ApplicationRunner {
+
+	public static void main(String[] args) {
+		SpringApplication.run(LoadGeneratorApplication.class, args);
+	}
+
+	private final Logger logger = LoggerFactory.getLogger(LoadGeneratorApplication.class);
+
+	@Override
+	public void run(ApplicationArguments applicationArguments) throws Exception {
+		final DataFlowTemplate dataFlowTemplate = getDataFlowTemplate(null, null, "http://localhost:9393");
+
+		importApps(dataFlowTemplate);
+
+		final Map<String, String> templateTaskDefinitions = new HashMap<>();
+		templateTaskDefinitions.put("timestamp", "timestamp");
+		templateTaskDefinitions.put("timestamp-batch", "timestamp-batch");
+
+		final TaskOperations taskOperations = dataFlowTemplate.taskOperations();
+
+		final int numberOfDesiredTaskDefinitions = 100;
+
+		final Set<TaskDefinitionResource> taskDefinitions = new HashSet<>(numberOfDesiredTaskDefinitions*templateTaskDefinitions.size());
+
+		for (java.util.Map.Entry<String, String> entry : templateTaskDefinitions.entrySet()) {
+			for (int i = 1; i <= numberOfDesiredTaskDefinitions; i++) {
+				final TaskDefinitionResource createdTaskDefinition = taskOperations.create(entry.getKey() + "_" + i, entry.getValue());
+				taskDefinitions.add(createdTaskDefinition);
+			}
+		}
+
+		logger.info("\n\nCreated a total of {} Task Definitions.\n", taskDefinitions.size());
+
+		final Set<Long> executions = new HashSet<>(0);
+		int numberOfDesiredExecutions = 20;
+
+		for (TaskDefinitionResource taskDefinition : taskDefinitions) {
+			final Set<Long> executionsPerTaskDefinition = new HashSet<>(0);
+			while (executionsPerTaskDefinition.size() < numberOfDesiredExecutions) {
+				CurrentTaskExecutionsResource c = taskOperations.currentTaskExecutions().iterator().next();
+				long runningExecutions = c.getRunningExecutionCount();
+				long maxExecutions = c.getMaximumTaskExecutions();
+				long delta = maxExecutions - runningExecutions;
+
+				if (delta > 0) {
+					long executionId = taskOperations.launch(taskDefinition.getName(), new HashMap<>(), new ArrayList<>());
+					executionsPerTaskDefinition.add(executionId);
+				}
+
+				Thread.sleep(200);
+			}
+			executions.addAll(executionsPerTaskDefinition);
+		}
+
+		logger.info("\n\nCreated a total of {} task executions.", executions.size());
+	}
+
+	private void importApps(DataFlowTemplate dataFlowTemplate) {
+		final String taskAppRegistrationUrl = "https://dataflow.spring.io/Elston-GA-task-applications-maven";
+		final String appRegistrationUrl = "https://dataflow.spring.io/Einstein-SR3-stream-applications-rabbit-maven";
+		logger.info("\n\nImporting Stream Applications from: {}.\n", appRegistrationUrl);
+		logger.info("\n\nImporting Task Applications from: {}.\n", taskAppRegistrationUrl);
+
+		final PagedResources<AppRegistrationResource> appRegistrations =
+			dataFlowTemplate.appRegistryOperations().importFromResource(appRegistrationUrl, false);
+
+		final PagedResources<AppRegistrationResource> taskAppRegistrations =
+				dataFlowTemplate.appRegistryOperations().importFromResource(taskAppRegistrationUrl, false);
+
+		logger.info("Imported {} Stream Applications. Showing the first {} from page {}",
+			appRegistrations.getMetadata().getTotalElements(),
+			appRegistrations.getMetadata().getSize(),
+			appRegistrations.getMetadata().getNumber());
+
+		for (AppRegistrationResource app : appRegistrations.getContent()) {
+			logger.info("{} (type: {})", app.getName(), app.getType());
+		}
+
+		logger.info("Imported {} Task Applications. Showing the first {} from page {}",
+				taskAppRegistrations.getMetadata().getTotalElements(),
+				taskAppRegistrations.getMetadata().getSize(),
+				taskAppRegistrations.getMetadata().getNumber());
+
+		for (AppRegistrationResource app : taskAppRegistrations.getContent()) {
+			logger.info("{} (type: {})", app.getName(), app.getType());
+		}
+
+	}
+
+	private static DataFlowTemplate getDataFlowTemplate(String username, String password, String target) {
+		final URI targetUri = URI.create(target);
+
+		final RestTemplate restTemplate = DataFlowTemplate.getDefaultDataflowRestTemplate();
+
+		if (username != null && password != null) {
+			final HttpClientConfigurer httpClientConfigurer = HttpClientConfigurer.create(targetUri);
+			httpClientConfigurer.basicAuthCredentials(username, password);
+			restTemplate.setRequestFactory(httpClientConfigurer.buildClientHttpRequestFactory());
+		}
+
+		final DataFlowTemplate dataFlowTemplate = new DataFlowTemplate(targetUri, restTemplate);
+
+		return dataFlowTemplate;
+	}
+}