[[cli]]
= Spring Boot CLI

[partintro]
--
The Spring Boot CLI is a command line tool that you can use if you want to quickly develop
a Spring application. It lets you run Groovy scripts, which means that you have a familiar
Java-like syntax without so much boilerplate code. You can also bootstrap a new project or
write your own command for it.
--



[[cli-installation]]
== Installing the CLI
The Spring Boot CLI (Command-Line Interface) can be installed manually by using SDKMAN!
(the SDK Manager) or by using Homebrew or MacPorts if you are an OSX user. See
_<<getting-started.adoc#getting-started-installing-the-cli>>_ in the "`Getting started`"
section for comprehensive installation instructions.



[[cli-using-the-cli]]
== Using the CLI
Once you have installed the CLI, you can run it by typing `spring` and pressing Enter at
the command line. If you run `spring` without any arguments, a simple help screen is
displayed, as follows:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring
	usage: spring [--help] [--version]
	       <command> [<args>]

	Available commands are:

	  run [options] <files> [--] [args]
	    Run a spring groovy script

	  _... more command help is shown here_
----

You can type `spring help` to get more details about any of the supported commands, as
shown in the following example:

[indent=0]
----
	$ spring help run
	spring run - Run a spring groovy script

	usage: spring run [options] <files> [--] [args]

	Option                     Description
	------                     -----------
	--autoconfigure [Boolean]  Add autoconfigure compiler
	                             transformations (default: true)
	--classpath, -cp           Additional classpath entries
	-e, --edit                 Open the file with the default system
	                             editor
	--no-guess-dependencies    Do not attempt to guess dependencies
	--no-guess-imports         Do not attempt to guess imports
	-q, --quiet                Quiet logging
	-v, --verbose              Verbose logging of dependency
	                             resolution
	--watch                    Watch the specified file for changes
----

The `version` command provides a quick way to check which version of Spring Boot you are
using, as follows:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring version
	Spring CLI v{spring-boot-version}
----



[[cli-run]]
=== Running Applications with the CLI
You can compile and run Groovy source code by using the `run` command. The Spring Boot CLI
is completely self-contained, so you do not need any external Groovy installation.

The following example shows a "`hello world`" web application written in Groovy:

.hello.groovy
[source,groovy,indent=0,subs="verbatim,quotes,attributes"]
----
	@RestController
	class WebApplication {

		@RequestMapping("/")
		String home() {
			"Hello World!"
		}

	}
----

To compile and run the application, type the following command:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring run hello.groovy
----

To pass command-line arguments to the application, use `--` to separate the commands
from the "`spring`" command arguments, as shown in the following example:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring run hello.groovy -- --server.port=9000
----

To set JVM command line arguments, you can use the `JAVA_OPTS` environment variable, as
shown in the following example:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ JAVA_OPTS=-Xmx1024m spring run hello.groovy
----

NOTE: When setting `JAVA_OPTS` on Microsoft Windows, make sure to quote the entire
instruction, such as `set "JAVA_OPTS=-Xms256m -Xmx2048m"`. Doing so ensures the values
are properly passed to the process.

[[cli-deduced-grab-annotations]]
==== Deduced "`grab`" Dependencies
Standard Groovy includes a `@Grab` annotation, which lets you declare dependencies on
third-party libraries. This useful technique lets Groovy download jars in the same way as
Maven or Gradle would but without requiring you to use a build tool.

Spring Boot extends this technique further and tries to deduce which libraries to "`grab`"
based on your code. For example, since the `WebApplication` code shown previously uses
`@RestController` annotations, Spring Boot grabs "Tomcat" and "Spring MVC".

The following items are used as "`grab hints`":

|===
| Items | Grabs

|`JdbcTemplate`, `NamedParameterJdbcTemplate`, `DataSource`
|JDBC Application.

|`@EnableJms`
|JMS Application.

|`@EnableCaching`
|Caching abstraction.

|`@Test`
|JUnit.

|`@EnableRabbit`
|RabbitMQ.

|extends `Specification`
|Spock test.

|`@EnableBatchProcessing`
|Spring Batch.

|`@MessageEndpoint` `@EnableIntegration`
|Spring Integration.

|`@Controller` `@RestController` `@EnableWebMvc`
|Spring MVC + Embedded Tomcat.

|`@EnableWebSecurity`
|Spring Security.

|`@EnableTransactionManagement`
|Spring Transaction Management.
|===

TIP: See subclasses of
{sc-spring-boot-cli}/compiler/CompilerAutoConfiguration.{sc-ext}[`CompilerAutoConfiguration`]
in the Spring Boot CLI source code to understand exactly how customizations are applied.



[[cli-default-grab-deduced-coordinates]]
==== Deduced "`grab`" Coordinates
Spring Boot extends Groovy's standard `@Grab` support by letting you specify a dependency
without a group or version (for example, `@Grab('freemarker')`). Doing so consults Spring
Boot's default dependency metadata to deduce the artifact's group and version.

NOTE: The default metadata is tied to the version of the CLI that you use. it changes only
when you move to a new version of the CLI, putting you in control of when the versions of
your dependencies may change. A table showing the dependencies and their versions that are
included in the default metadata can be found in the <<appendix-dependency-versions,
appendix>>.



[[cli-default-import-statements]]
==== Default Import Statements
To help reduce the size of your Groovy code, several `import` statements are automatically
included. Notice how the preceding example refers to `@Component`, `@RestController`, and
`@RequestMapping` without needing to use fully-qualified names or `import` statements.

TIP: Many Spring annotations work without using `import` statements. Try running your
application to see what fails before adding imports.



[[cli-automatic-main-method]]
==== Automatic Main Method
Unlike the equivalent Java application, you do not need to include a
`public static void main(String[] args)` method with your `Groovy` scripts. A
`SpringApplication` is automatically created, with your compiled code acting as the
`source`.



[[cli-default-grab-deduced-coordinates-custom-dependency-management]]
==== Custom Dependency Management
By default, the CLI uses the dependency management declared in `spring-boot-dependencies`
when resolving `@Grab` dependencies. Additional dependency management, which overrides
the default dependency management, can be configured by using the
`@DependencyManagementBom` annotation. The annotation's value should specify the
coordinates (`groupId:artifactId:version`) of one or more Maven BOMs.

For example, consider the following declaration:

[source,groovy,indent=0]
----
	@DependencyManagementBom("com.example.custom-bom:1.0.0")
----

The preceding declaration picks up `custom-bom-1.0.0.pom` in a Maven repository under
`com/example/custom-versions/1.0.0/`.

When you specify multiple BOMs, they are applied in the order in which you declare them,
as shown in the following example:

[source,java,indent=0]
----
	@DependencyManagementBom(["com.example.custom-bom:1.0.0",
			"com.example.another-bom:1.0.0"])
----

The preceding example indicates that the dependency management in `another-bom` overrides
the dependency management in `custom-bom`.

You can use `@DependencyManagementBom` anywhere that you can use `@Grab`. However, to
ensure consistent ordering of the dependency management, you can use
`@DependencyManagementBom` at most once in your application. A useful source of dependency
management (which is a superset of Spring Boot's dependency management) is the
https://platform.spring.io/[Spring IO Platform], which you might include with the following
line:

[source,java,indent=0]
----
@DependencyManagementBom('io.spring.platform:platform-bom:1.1.2.RELEASE')
----


[[cli-multiple-source-files]]
=== Applications with Multiple Source Files
You can use "`shell globbing`" with all commands that accept file input. Doing so lets
you use multiple files from a single directory, as shown in the following example:

[indent=0]
----
	$ spring run *.groovy
----



[[cli-jar]]
=== Packaging Your Application
You can use the `jar` command to package your application into a self-contained executable
jar file, as shown in the following example:

[indent=0]
----
	$ spring jar my-app.jar *.groovy
----

The resulting jar contains the classes produced by compiling the application and all of
the application's dependencies so that it can then be run by using `java -jar`. The jar
file also contains entries from the application's classpath. You can add and remove
explicit paths to the jar by using `--include` and `--exclude`. Both are comma-separated,
and both accept prefixes, in the form of "`+`" and "`-`", to signify that they should be
removed from the defaults. The default includes are as follows:

[indent=0]
----
	public/**, resources/**, static/**, templates/**, META-INF/**, *
----

The default excludes are as follows:

[indent=0]
----
	.*, repository/**, build/**, target/**, **/*.jar, **/*.groovy
----

Type `spring help jar` on the command line for more information.



[[cli-init]]
=== Initialize a New Project
The `init` command lets you create a new project by using https://start.spring.io without
leaving the shell, as shown in the following example:

[indent=0]
----
	$ spring init --dependencies=web,data-jpa my-project
	Using service at https://start.spring.io
	Project extracted to '/Users/developer/example/my-project'
----

The preceding example creates a `my-project` directory with a Maven-based project that
uses `spring-boot-starter-web` and `spring-boot-starter-data-jpa`. You can list the
capabilities of the service by using the `--list` flag, as shown in the following example:

[indent=0]
----
	$ spring init --list
	=======================================
	Capabilities of https://start.spring.io
	=======================================

	Available dependencies:
	-----------------------
	actuator - Actuator: Production ready features to help you monitor and manage your application
	...
	web - Web: Support for full-stack web development, including Tomcat and spring-webmvc
	websocket - Websocket: Support for WebSocket development
	ws - WS: Support for Spring Web Services

	Available project types:
	------------------------
	gradle-build -  Gradle Config [format:build, build:gradle]
	gradle-project -  Gradle Project [format:project, build:gradle]
	maven-build -  Maven POM [format:build, build:maven]
	maven-project -  Maven Project [format:project, build:maven] (default)

	...
----

The `init` command supports many options. See the `help` output for more details. For
instance, the following command creates a Gradle project that uses Java 8 and `war`
packaging:

[indent=0]
----
	$ spring init --build=gradle --java-version=1.8 --dependencies=websocket --packaging=war sample-app.zip
	Using service at https://start.spring.io
	Content saved to 'sample-app.zip'
----



[[cli-shell]]
=== Using the Embedded Shell
Spring Boot includes command-line completion scripts for the BASH and zsh shells. If you
do not use either of these shells (perhaps you are a Windows user), you can use the
`shell` command to launch an integrated shell, as shown in the following example:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring shell
	*Spring Boot* (v{spring-boot-version})
	Hit TAB to complete. Type \'help' and hit RETURN for help, and \'exit' to quit.
----

From inside the embedded shell, you can run other commands directly:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ version
	Spring CLI v{spring-boot-version}
----

The embedded shell supports ANSI color output as well as `tab` completion. If you need to
run a native command, you can use the `!` prefix. To exit the embedded shell, press
`ctrl-c`.



[[cli-install-uninstall]]
=== Adding Extensions to the CLI
You can add extensions to the CLI by using the `install` command. The command takes one
or more sets of artifact coordinates in the format `group:artifact:version`, as shown in
the following example:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring install com.example:spring-boot-cli-extension:1.0.0.RELEASE
----

In addition to installing the artifacts identified by the coordinates you supply, all of
the artifacts' dependencies are also installed.

To uninstall a dependency, use the `uninstall` command. As with the `install` command, it
takes one or more sets of artifact coordinates in the format of `group:artifact:version`,
as shown in the following example:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring uninstall com.example:spring-boot-cli-extension:1.0.0.RELEASE
----

It uninstalls the artifacts identified by the coordinates you supply and their
dependencies.

To uninstall all additional dependencies, you can use the `--all` option, as shown in the
following example:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ spring uninstall --all
----



[[cli-groovy-beans-dsl]]
== Developing Applications with the Groovy Beans DSL
Spring Framework 4.0 has native support for a `beans{}` "`DSL`" (borrowed from
https://grails.org/[Grails]), and you can embed bean definitions in your Groovy application
scripts by using the same format. This is sometimes a good way to include external
features like middleware declarations, as shown in the following example:

[source,groovy,indent=0]
----
	@Configuration
	class Application implements CommandLineRunner {

		@Autowired
		SharedService service

		@Override
		void run(String... args) {
			println service.message
		}

	}

	import my.company.SharedService

	beans {
		service(SharedService) {
			message = "Hello World"
		}
	}
----

You can mix class declarations with `beans{}` in the same file as long as they stay at
the top level, or, if you prefer, you can put the beans DSL in a separate file.



[[cli-maven-settings]]
== Configuring the CLI with `settings.xml`
The Spring Boot CLI uses Aether, Maven's dependency resolution engine, to resolve
dependencies. The CLI makes use of the Maven configuration found in `~/.m2/settings.xml`
to configure Aether. The following configuration settings are honored by the CLI:

* Offline
* Mirrors
* Servers
* Proxies
* Profiles
** Activation
** Repositories
* Active profiles

See https://maven.apache.org/settings.html[Maven's settings documentation] for further
information.



[[cli-whats-next]]
== What to Read Next
There are some {github-code}/spring-boot-project/spring-boot-cli/samples[sample groovy
scripts] available from the GitHub repository that you can use to try out the Spring Boot
CLI. There is also extensive Javadoc throughout the {sc-spring-boot-cli}[source code].

If you find that you reach the limit of the CLI tool, you probably want to look at
converting your application to a full Gradle or Maven built "`Groovy project`". The
next section covers Spring Boot's "<<build-tool-plugins.adoc#build-tool-plugins, Build
tool plugins>>", which you can use with Gradle or Maven.
