Working with plugins

Logstash has a rich collection of input, filter, codec and output plugins. Plugins are available as self-contained packages called gems and hosted on RubyGems.org. The plugin manager accessed via bin/logstash-plugin script is used to manage the lifecycle of plugins in your Logstash deployment. You can install, remove and upgrade plugins using the Command Line Interface (CLI) invocations described below.

The majority of the plugin manager commands require access to the internet to reach RubyGems.org. If your organization is behind a firewall you can set these environments variables to configure Logstash to use your proxy.

export http_proxy=http://localhost:3128
export https_proxy=http://localhost:3128

Logstash release packages bundle common plugins so you can use them out of the box. To list the plugins currently available in your deployment:

bin/logstash-plugin list 
bin/logstash-plugin list --verbose 
bin/logstash-plugin list '*namefragment*' 
bin/logstash-plugin list --group output 

The most common situation when dealing with plugin installation is when you have access to internet. Using this method, you will be able to retrieve plugins hosted on the public repository (RubyGems.org) and install on top of your Logstash installation.

bin/logstash-plugin install logstash-output-kafka

Once the plugin is successfully installed, you can start using it in your configuration file.

In some cases, you want to install plugins which have not yet been released and not hosted on RubyGems.org. Logstash provides you the option to install a locally built plugin which is packaged as a ruby gem. Using a file location:

bin/logstash-plugin install /path/to/logstash-output-kafka-1.0.0.gem

Using the Logstash --path.plugins flag, you can load a plugin source code located on your file system. Typically this is used by developers who are iterating on a custom plugin and want to test it before creating a ruby gem.

The path needs to be in a specific directory hierarchy: PATH/logstash/TYPE/NAME.rb, where TYPE is inputs filters, outputs or codecs and NAME is the name of the plugin.

# supposing the code is in /opt/shared/lib/logstash/inputs/my-custom-plugin-code.rb
bin/logstash --path.plugins /opt/shared/lib

Plugins have their own release cycle and are often released independent of Logstash’s core release cycle. Using the update subcommand you can get the latest version of the plugin.

bin/logstash-plugin update 
bin/logstash-plugin update logstash-output-kafka 

If you need to remove plugins from your Logstash installation:

bin/logstash-plugin remove logstash-output-kafka

The previous sections relied on Logstash being able to communicate with RubyGems.org. In certain environments, Forwarding Proxy is used to handle HTTP requests. Logstash Plugins can be installed and updated through a Proxy by setting the HTTP_PROXY environment variable:

export HTTP_PROXY=http://127.0.0.1:3128

bin/logstash-plugin install logstash-output-kafka

Once set, plugin commands install, update can be used through this proxy.