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1. Introduction

In this tutorial you will learn how to extend your Command by adding Lite Services that are made available by the executing Engine.

This guide merely demonstrates how to extend a Command. For more information on how to use the Command in the apps, refer to this guide.

2. Prerequisites

To complete this guide you need:

  • Roughly 10 minutes

  • JDK 11+ installed with JAVA_HOME configured appropriately

  • An IDE (we recommend IntelliJ)

  • Some kind of build tool (like gradle, maven or ant)

  • Basic understanding of Commands and the respective annotations

  • Preferably the completion of the step-by-step guide

3. What is a Command Service?

Services mostly handle tasks that are relevant to the executing environment in some way, for example the IPersistenceService, which is responsible for accessing data.

A Lite Service is a special kind of service which is only available to Commands. They can be used to extract relevant business logic or make use of the Engines services.

3.1. Available Services

When executing your command in the Workflow Executor, the following services will always be available.

  • IJsonMapper: Handles the conversion between java objects and JSON and resolves json paths

  • ICommandRestService: Provides web targets which can be used to perform REST actions

  • ILiteServiceProvider: Collection of all available Command Services that a Command may use

4. Example Implementation

In our case, we want to develop a simple Command which can resolve a JSON path within a given object.

4.1. Building the Command

The basic structure of a Command should be known, and will in our case look like the following code snippet.

/**
 * @workflowDocu Simple command that resolves a given JSON path for the
 * given JSON string.
 */
@JavaCommand
@CommandGroup("org.example")
public class ResolveJsonPath {

	/**
         * @workflowDocu The JSON string to look in
         */
	@Persistent
	private String jsonString; (1)

	/**
         * @workflowDocu The JSON path to search
         */
	@Persistent
	private String jsonPath; (2)

	/**
         * @workflowDocu Result of the operation
         */
	@Persistent(scope = FieldScope.WRITE_ONLY)
	private String resolvedPath; (3)

	@Run
	public void resolveJsonPath() {
		// TODO: Fetch the JSON path
	}
}
1 Our first input parameter will be the JSON string that we want to traverse
2 Our second input is the JSON path which we will try to resolve in the given JSON string
3 The output will be the result of our operation

Resolving a JSON path by hand would be too much work for ourselves, but we also want to keep our implementation inline with the Engine. In order to achieve that we use the IJsonMapper, which already is a service of the Engine.

4.2. Building the Command Service

/**
 * Service class which provides JSON path functionality.
 */
public class JsonPathService implements ILiteService { (1)
    @InjectService (2)
    private IJsonMapper jsonMapper;

    /**
     * Resolves a given JSON path in the given object using the Engine's json mapper.
     *
     * @param object Object to look in
     * @param path Path to look for
     * @return Resolved JSON path
     */
    (3)
    public String fetchJsonPath(final String object, final String path) {
        return this.jsonMapper.resolvePathIn(object, path.split("\\."));
    }
}
1 Every Lite Service needs to implement the marker ILiteService
2 Inside the scope of a Lite Service we can freely inject services of the Engine into our service by using the @InjectService annotation
3 Our implementation merely delegates the call to the Engines IJsonMapper.
Due to the nature of services being interfaces, are dependent on your runtime. For example, when running the Command in the Workflow Executor the IJsonMapper functions as a bridge to Jackson and may not handle the complete JSON path syntax.

4.3. Extending the Command

After building our Lite Service we can now extend our Command using the @LiteService annotation. In order to do so, we must create a new resource folder META-INF\services. There, we create a new file called „de.asap.pak.core.commandservices.api.ILiteService“ with one line „org.example.JsonPathService“.

Make sure your file has no extension (.txt etc)
/**
 * @workflowDocu Simple command that resolves a given JSON path for the
 * given JSON string.
 */
@JavaCommand
@CommandGroup("org.example")
public class ResolveJsonPath {
	/**
         * @workflowDocu Service which provides the ability to resolve JSON paths
         */
	@LiteService (1)
	private JsonPathService jsonService;

	/**
         * @workflowDocu The JSON string to look in
         */
	@Persistent
	private String jsonString;

	/**
         * @workflowDocu The JSON path to search
         */
	@Persistent
	private String jsonPath;

	/**
         * @workflowDocu Result of the operation
         */
	@Persistent(scope = FieldScope.WRITE_ONLY)
	private String resolvedPath;

	@Run
	public void resolveJsonPath() {
		this.resolvedPath = this.jsonService.fetchJsonPath(this.jsonString, this.jsonPath);
	}
}
1 Our Service will be injected into our Command using the @LiteService annotation

5. What to do next?

After creating the Command, you might be curious on how to use it in one of our apps or smoke testing it within the Workflow Executor.

Sonatype Nexus

PAK features connectors and commands for Sonatype Nexus. This means the software can directly interact with Nexus repositories for storing and managing artifacts. Through these connectors, PAK can automate tasks like uploading binaries or retrieving dependencies, ensuring efficient artifact management within Nexus.

Jenkins

PAK has connectors and commands for Jenkins. This allows the software to directly communicate with Jenkins servers, enabling the automation of CI/CD (Continuous Integration/Continuous Deployment) tasks. Through these connectors, PAK can trigger builds, fetch build statuses, or manage job configurations, streamlining the CI/CD processes within Jenkins.

Git Hub

PAK possesses connectors and commands for GitHub. This means the software can interface directly with GitHub repositories, facilitating actions like code pushes, pull requests, or issue tracking. Through these connectors, PAK can automate various GitHub operations, enhancing code collaboration and repository management.

Atlassian Confluence

PAK is equipped with connectors and commands for Atlassian Confluence. This enables the software to directly interact with Confluence spaces and pages. Through these connectors, PAK can automate actions such as creating, updating, or retrieving documentation, ensuring efficient content management and collaboration within Confluence.

Codebeamer

PAK features connectors and commands for Codebeamer. This allows the software to seamlessly integrate with Codebeamer’s ALM (Application Lifecycle Management) platform. Through these connectors, PAK can automate tasks like issue tracking, test management, or requirements tracing, enhancing the coordination and management of software development processes.

JFrog Artifactory

PAK has connectors and commands for JFrog Artifactory. This means the software can directly interface with Artifactory repositories, enabling actions like artifact storage, retrieval, and management. Through these connectors, PAK can automate tasks such as deploying artifacts or managing repository configurations, streamlining the integration and management of binary artifacts within Artifactory.

Amazon Web Services (AWS)

PAK has connectors and commands for Amazon Web Services (AWS). This means the software possesses specialized interfaces to directly interact with AWS services and execute actions on the AWS platform. Through these connectors, PAK can automate AWS-specific commands, such as launching EC2 instances, managing S3 buckets, or configuring Lambda functions. This allows for efficient integration, management, and automation of AWS resources and services directly from PAK.

Atlassian Jira

PAK features integration tools and capabilities for Atlassian Jira. These tools allow for a direct connection to Jira and the execution of specific actions. Using these integration tools, PAK can automate Jira actions such as adding comments or changing ticket priorities, ensuring seamless handling and coordination of Jira processes.

Git

PAK has connectors and commands for Git. This means it has interfaces to directly communicate with Git and execute actions. Through these connectors, the software can automate Git commands such as retrieving changes or creating branches, enabling efficient integration and management of Git tasks.

Generic Human Tasks

PAK offers you a standard set of commands which require creative input from the user. Enables you to start with automating your workflows, that still need abit of human input.

Generic Commands

PAK offers a standard set of commands giving you the first steps to automate your workflows.

Nexus Maven Command Pool

Nexus is an artifact repository manager for storing binaries, libraries, and artifacts, supporting formats like Maven. Maven, a software project management tool, is based on the Project Object Model (POM) and allows developers to consistently define projects and dependencies. Our Command Pool offers commands for interactions between Maven and Nexus, such as artifact uploads or dependency retrieval.

Artifactory Maven Command Pool

Artifactory allows developers to store, retrieve, and manage binary files and artifacts, providing a
central source for all binaries used in a development process. Apache Maven is a software project
management and comprehension tool that enables developers to consistently describe a project and
its dependencies. Our Command Pool offers a collection of commands used to facilitate interactions
between Maven and Artifactory, such as uploading artifacts or retrieving dependencies.

Open API Command Interpreter

The OpenApi Command Interpreter allows you the automatic parsing of commands from an OpenApi defintion. No additional code needs to be written anymore, just add the address to the definition and our framework does the rest!

Kotlin Command Interpreter

The Kotlin Command Interpreter allows you the parsing and execution of commands within a Kotlin environment to automate various tasks or processes.

Bpmn Interpreter

Workflows come in many shapes and forms. The BPMN (Business Process Model and Notation) Interpreter enables the parsing of worklows defined in the BPMN format into the PAK intern model.

Human Task Interpreter

The Human Task Interpreter allows you the parsing and running of commands within a HTML and Javascript environment. Use this to build commands which need the creative input of a workflow user!

Java Command Interpreter

The Java Command Interpreter allows you the parsing and execution of commands within a Java
environment to automate various tasks or processes.

Core

The heart of the PAK-Framework. Contains the means to run workflows with the PAK engine, but also the possibility to enrich the frameworks interfaces with your own implementations and solutions.

RocksDB Persistence

Data that is generated by a workflow run needs to be saved for short or longer terms. Our solution to the Persistence Interface of the PAK-Framework is to use the high-performance, key-value based RocksDB developed by Facebook.

PAK online

PAK Online is a web based application and provides an Open API based REST API. It enables you to upload workflows and run them periodically or on REST demand.

Command Line App

Run tasks and workflows on the console or as part of a CI/CD Pipeline with our Command Line Interface.

Workflow Editor

With our specially developed editor, a wide variety of workflows can be easily modeled in the wide known BPMN process format.

Workflow Executor

The Workflow Executor is the application to run your workflows. It features a multilingual UI and easy managment of your favorite workflows.

Support

We offer a community website where you can exchange ideas and support each other. For our Pro packages we also offer full support via email.