#### Install dependencies with gradle (recommended)[^1]
* Install development dependencies

* Install default plugins and other dependencies

Verify the installation  Copy Section
To verify your environment, run the following to start Logstash and send your first event:

This should start Logstash with stdin input waiting for you to enter an event

Advanced: Drip Launcher
Drip is a tool that solves the slow JVM startup problem while developing Logstash. The drip script is intended to be a drop-in replacement for the java command. We recommend using drip during development, in particular for running tests. Using drip, the first invocation of a command will not be faster but the subsequent commands will be swift.
To tell logstash to use drip, set the environment variable  JAVACMD=which drip .
Example (but see the Testing section below before running rspec for the first time):
    JAVACMD=which drip bin/rspec
Caveats
Drip does not work with STDIN. You cannot use drip for running configs which use the stdin plugin.
Building Logstash Documentation  Copy Chapter
To build the Logstash Reference (open source content only) on your local
machine, clone the following repos:
logstash - contains main docs about core features
logstash-docs - contains generated plugin docs
docs - contains doc build files
Make sure you have the same branch checked out in logstash and logstash-docs.
Check out master in the docs repo.
Run the doc build script from within the docs repo. For example:

Testing  Copy Chapter
Most of the unit tests in Logstash are written using rspec for the Ruby parts. For the Java parts, we use junit. For testing you can use the test rake tasks and the bin/rspec command, see instructions below:
Core tests  Copy Section
1- To run the core tests you can use the Gradle task:
    ./gradlew test
  or use the rspec tool to run all tests or run a specific test:
    bin/rspec
    bin/rspec spec/foo/bar_spec.rb
  Note that before running the rspec command for the first time you need to set up the RSpec test dependencies by running:
    ./gradlew bootstrap
2- To run the subset of tests covering the Java codebase only run:
    ./gradlew javaTests
3- To execute the complete test-suite including the integration tests run:
    ./gradlew check
4- To execute a single Ruby test run:
    SPEC_OPTS="-fd -P logstash-core/spec/logstash/api/commands/default_metadata_spec.rb" ./gradlew :logstash-core:rubyTests --tests org.logstash.RSpecTests
5- To execute single spec for integration test, run:
    ./gradlew integrationTests -PrubyIntegrationSpecs=specs/slowlog_spec.rb
Sometimes you might find a change to a piece of Logstash code causes a test to hang. These can be hard to debug.
If you set LS_JAVA_OPTS="-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005" you can connect to a running Logstash with your IDEs debugger which can be a great way of finding the issue.
Plugins tests  Copy Section
To run the tests of all currently installed plugins:
    rake test:plugins
You can install the default set of plugins included in the logstash package:
    rake test:install-default
---
Note that if a plugin is installed using the plugin manager bin/logstash-plugin install ... do not forget to also install the plugins development dependencies using the following command after the plugin installation:
    bin/logstash-plugin install --development
Building Artifacts  Copy Chapter
Built artifacts will be placed in the LS_HOME/build directory, and will create the directory if it is not already present.
You can build a Logstash snapshot package as tarball or zip file

OSS-only artifacts can similarly be built with their own gradle tasks:

You can also build .rpm and .deb, but the fpm tool is required.

and:

Using a Custom JRuby Distribution  Copy Chapter
If you want the build to use a custom JRuby you can do so by setting a path to a custom
JRuby distribution's source root via the custom.jruby.path Gradle property.
E.g.

Project Principles  Copy Chapter
* Community: If a newbie has a bad time, it's a bug.
* Software: Make it work, then make it right, then make it fast.
* Technology: If it doesn't do a thing today, we can make it do it tomorrow.
Contributing  Copy Chapter
All contributions are welcome: ideas, patches, documentation, bug reports,
complaints, and even something you drew up on a napkin.
Programming is not a required skill. Whatever you've seen about open source and
maintainers or community members saying "send patches or die" - you will not
see that here.
It is more important that you are able to contribute.
For more information about contributing, see the
CONTRIBUTING file.
Footnotes  Copy Chapter
[^1]: <details><summary>Use bundle instead of gradle to install dependencies</summary>
    #### Alternatively, instead of using gradle you can also use bundle:
    * Install development dependencies

* Bootstrap the environment:

* You can then use bin/logstash to start Logstash, but there are no plugins installed. To install default plugins, you can run: