README.md

Gimme a CLI Starter Project

This project is an example starter project for the Gimme a CLI library.

This project can be forked and used as a starting point for creating your own CLI.

Features

The starter project includes:

• Gimme a CLI - a Java library for creating quick and easy CLIs using JCommander and Spring dependency injection.
• An example Hello World command.
• An example --version command.
• Shadow Plugin gradle setup to make it easy to distribute your CLI. The Shadow plugin creates a fat jar with all dependencies, sh and .bat wrapper scripts, and .tar and .zip distributions.

Usage

1. Install the Java 11 OpenJDK.

2. Fork this project.

3. Find/replace mycli with the name of your CLI.

4. Define one or more commands for your CLI by implementing the Command interface. Optionally use JCommander annotations to define command arguments and options.

   import com.beust.jcommander.Parameter;
   import com.beust.jcommander.Parameters;
   import com.nike.gimme.a.cli.Command;
   
   @Parameters(commandNames = "hello",
               commandDescription = "Prints \"Hello <name>\" to the terminal")
   public class HelloWorldCommand implements Command {
   
       private final Logger log = LoggerFactory.getLogger(getClass());
   
       @Parameter(names = {"--name"}, required = true)
       private String name;
       
       @Override
       public void execute() {
           log.info("Hello " + name);
       }
   }

   Commands are automatically instantiated as Spring beans (e.g. dependencies can be supplied via constructor injection, etc).

5. Build and run

   # Create the distribution
   ./gradlew shadowDistTar
   
   # Extract it
   tar xf build/distributions/mycli-shadow-1.0.0-SNAPSHOT.tar
   
   # Run the CLI
   mycli-shadow-1.0.0-SNAPSHOT/bin/mycli --help

6. Optionally define gradle tasks for running CLI commands

   task helloWorldFromGradle(type: CliExec) {
       description = "Example of defining a CLI command as a Gradle task"
   
       // arguments to pass to the application
       args 'hello', '--name', 'world from gradle'
   }

   This lets you quickly run commands locally without building archives.

References

• Gimme a CLI - the library that this project is a "starter project" for.
• JCommander - a library for CLI argument parsing.
• Spring's IoC - a library for dependency injection.
• Shadow Plugin - a gradle plugin for creating a single output jar. Makes it easy to distribute your CLI to share with others.