# Groovy Scripting

This add-on provides support for Groovy (opens new window) 4.0.11 that can be used as a scripting language within automation rules and which eliminates the need to manually install Groovy.

# Creating Groovy Scripts

When this add-on is installed, you can select Groovy as a scripting language when creating a script action within the rule editor of the UI.

Alternatively, you can create scripts in the automation/jsr223 configuration directory. If you create an empty file called test.groovy, you will see a log line with information similar to:

    ... [INFO ] [.a.m.s.r.i.l.ScriptFileWatcher:150  ] - Loading script 'test.groovy'

To enable debug logging, use the console logging commands to enable debug logging for the automation functionality:

log:set DEBUG org.openhab.core.automation

For more information on the available APIs in scripts see the JSR223 Scripting documentation.

# Code reuse

One can place *.groovy files with Groovy classes under automation/groovy configuration directory.
Those classes can be imported in JSR-223 scripts or the UI rules action with the usual Groovy import statement.

To apply shared code changes, one has to restart the openHAB Core :: Bundles :: Automation bundle on the Console or an openHAB instance altogether.

# Script Examples

Groovy scripts provide access to almost all the functionality in an openHAB runtime environment. As a simple example, the following script logs "Hello, World!". Note that System.out.println will usually not work since the output has no terminal to display the text. The openHAB server uses the SLF4J (opens new window) library for logging.

import org.slf4j.LoggerFactory

LoggerFactory.getLogger("org.openhab.core.automation.examples").info("Hello, World!")

Depending on the openHAB logging configuration, you may need to prefix logger names with org.openhab.core.automation for them to show up in the log file (or you modify the logging configuration).

The script uses the LoggerFactory (opens new window) to obtain a named logger and then logs a message like:

    ... [INFO ] [.openhab.core.automation.examples:-2   ] - Hello, World!