Implement TaskLaunchRequestFunction

function/README.adoc

@@ -18,3 +18,43 @@ Transform incoming message payload based on a SpEL expression and produces an ou
 `filter-function`
 
 Filter an incoming message based on a boolean SpEL expression and produces that message or nothing according expression result.
+
+`task-launch-request-function`
+
+Transform input Message to a Message<TaskLaunchRequest>. The `TaskLaunchRequest` can be used as input to the `tasklauncher-function`.
+
+==== Task Launch Request
+
+The `TaskLaunchRequest` is a value object that is used to launch a task using a Data Flow server.
+The TaskLaunchRequest contains the name of the task to launch. This must the name of a defined task in Data Flow.
+You may optionally provide command line arguments and deployment properties. For more details, see `tasklauncher-function`.
+
+===== Task Name
+
+The task name is a required field. This may be statically configured by setting `task.launch.request.task-name`,
+or extracted from the Message by setting `task.launch.request.task-name-expression`.
+You may also provide a custom implementation of the `TaskNameMessageMapper` bean to enable more complex task name mappings.
+
+===== Task Command Line Arguments
+
+The task to be launched often requires additional data which is passed to the task as command line arguments.
+The `task.launch.request.args` property accepts a comma delimited string of key-value pairs, for example
+`key1=val1,key2=val2`. In addition, the  `task.launch.request.arg-expressions` property allows you to use SpEL expressions to evaluate
+message contents to extract command line arguments.
+For example, `task.launch.request.arg-expressions=foo=payload.toUpperCase(),bar=payload.substring(0,2)`.
+
+You may also provide a custom implementation of the `CommandLineArgumentsMessageMapper` bean to implement more complex logic.
+
+===== Task Deployment Properties
+
+Deployment properties are platform-specific configuration used by the `TaskLauncher` and are always statically configured by
+setting `task.launch.request.deployment-properties` and apply to every task launch request.
+
+NOTE: When embedding the `task-launch-request-function` into a Spring Boot application, it should be imported with
+`@ImportAutoConfiguration(TaskLaunchRequestFunctionConfiguration.class)`.
+This is required when providing custom bean definitions, as described above.
+Otherwise, the function configuration will not detect the provided beans.
+
+`TaskLaunchRequestFunctionTests` provides some configuration examples.
+
+

function/task-launch-request-function/pom.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+		 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<parent>
+		<groupId>io.pivotal.java.function</groupId>
+		<artifactId>spring-functions-parent</artifactId>
+		<version>1.0.0.BUILD-SNAPSHOT</version>
+		<relativePath>../../spring-functions-parent</relativePath>
+	</parent>
+
+	<modelVersion>4.0.0</modelVersion>
+
+	<artifactId>task-launch-request-function</artifactId>
+	<name>task-launch-request-function</name>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.integration</groupId>
+			<artifactId>spring-integration-core</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-json</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-validation</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+</project>

function/task-launch-request-function/src/main/java/io/pivotal/java/function/tasklaunchrequest/function/ExpressionEvaluatingTaskNameMessageMapper.java

@@ -0,0 +1,38 @@
+/*
+ * 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
+ *
+ *      https://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 io.pivotal.java.function.tasklaunchrequest.function;
+
+import io.pivotal.java.function.tasklaunchrequest.function.support.TaskNameMessageMapper;
+import org.springframework.expression.EvaluationContext;
+import org.springframework.expression.Expression;
+import org.springframework.messaging.Message;
+
+public class ExpressionEvaluatingTaskNameMessageMapper implements TaskNameMessageMapper {
+
+    private final Expression expression;
+    private final EvaluationContext evaluationContext;
+
+    public ExpressionEvaluatingTaskNameMessageMapper(Expression expression, EvaluationContext evaluationContext) {
+        this.evaluationContext = evaluationContext;
+        this.expression = expression;
+    }
+
+    @Override
+    public String processMessage(Message<?> message) {
+        return expression.getValue(evaluationContext, message).toString();
+    }
+}

function/task-launch-request-function/src/main/java/io/pivotal/java/function/tasklaunchrequest/function/KeyValueListParser.java

@@ -0,0 +1,66 @@
+/*
+ * 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
+ *
+ *      https://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 io.pivotal.java.function.tasklaunchrequest.function;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.util.StringUtils;
+
+/**
+ * Parses a comma delimited list of key value pairs in which the values can contain commas as well.
+ *
+ * @author Chris Schaeffer
+ * @author David Turanski
+ **/
+abstract class KeyValueListParser {
+
+	static Map<String, String> parseCommaDelimitedKeyValuePairs(String value) {
+		Map<String, String> keyValuePairs = new HashMap<>();
+
+		if (StringUtils.isEmpty(value)) {
+			return keyValuePairs;
+		}
+
+		ArrayList<String> pairs = new ArrayList<>();
+
+		String[] candidates = StringUtils.commaDelimitedListToStringArray(value);
+
+		for (int i = 0; i < candidates.length; i++) {
+			if (i > 0 && !candidates[i].contains("=")) {
+				pairs.add(pairs.get(pairs.size() - 1) + "," + candidates[i]);
+			}
+			else {
+				pairs.add(candidates[i]);
+			}
+		}
+
+		for (String pair : pairs) {
+			addKeyValuePair(pair, keyValuePairs);
+		}
+
+		return keyValuePairs;
+	}
+
+	private static void addKeyValuePair(String pair, Map<String, String> properties) {
+		int firstEquals = pair.indexOf('=');
+		if (firstEquals != -1) {
+			properties.put(pair.substring(0, firstEquals).trim(), pair.substring(firstEquals + 1).trim());
+		}
+	}
+}

function/task-launch-request-function/src/main/java/io/pivotal/java/function/tasklaunchrequest/function/TaskLaunchRequest.java

@@ -0,0 +1,64 @@
+/*
+ * 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
+ *
+ *      https://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 io.pivotal.java.function.tasklaunchrequest.function;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class TaskLaunchRequest {
+    @JsonProperty("args")
+    private List<String> commandlineArguments = new ArrayList<>();
+
+    @JsonProperty("deploymentProps")
+    private Map<String, String> deploymentProperties = new HashMap<>();
+
+    @JsonProperty("name")
+    private String taskName;
+
+    public void setCommandlineArguments(List<String> commandlineArguments) {
+        this.commandlineArguments = new ArrayList<>(commandlineArguments);
+    }
+
+    public List<String> getCommandlineArguments() {
+        return this.commandlineArguments;
+    }
+
+    public void setDeploymentProperties(Map<String, String> deploymentProperties) {
+        this.deploymentProperties = deploymentProperties;
+    }
+
+    public Map<String, String> getDeploymentProperties() {
+        return this.deploymentProperties;
+    }
+
+    public void setTaskName(String taskName) {
+        this.taskName = taskName;
+    }
+
+    public String getTaskName() {
+        return this.taskName;
+    }
+
+    public TaskLaunchRequest addCommmandLineArguments(Collection<String> args) {
+        this.commandlineArguments.addAll(args);
+        return this;
+    }
+}

function/task-launch-request-function/src/main/java/io/pivotal/java/function/tasklaunchrequest/function/TaskLaunchRequestFunction.java

@@ -0,0 +1,31 @@
+/*
+ * 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
+ *
+ *      https://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 io.pivotal.java.function.tasklaunchrequest.function;
+
+import java.util.function.Function;
+
+import org.springframework.messaging.Message;
+
+/**
+ * A marker interface useful for unambiguous dependency injection of this Function.
+ *
+ * @author David Turanski
+ **/
+@FunctionalInterface
+public interface TaskLaunchRequestFunction extends Function<Message<?>, Message<TaskLaunchRequest>> {
+
+}