cli-extending-plugins-writing.adoc

Writing CLI plug-ins

You can write a plug-in for the {product-title} CLI in any programming language or script that allows you to write command-line commands. Note that you can not use a plug-in to overwrite an existing oc command.

Important

OpenShift CLI plug-ins are currently a Technology Preview feature.

Procedure

This procedure creates a simple Bash plug-in that prints a message to the terminal when the oc foo command is issued.

1. Create a file called oc-foo.

   When naming your plug-in file, keep the following in mind:

   • The file must begin with oc- or kubectl- in order to be recognized as a plug-in.

   • The file name determines the command that invokes the plug-in. For example, a plug-in with the file name oc-foo-bar can be invoked by a command of oc foo bar. You can also use underscores if you want the command to contain dashes. For example, a plug-in with the file name oc-foo_bar can be invoked by a command of oc foo-bar.

2. Add the following contents to the file.

   #!/bin/bash
   
   # optional argument handling
   if [[ "$1" == "version" ]]
   then
       echo "1.0.0"
       exit 0
   fi
   
   # optional argument handling
   if [[ "$1" == "config" ]]
   then
       echo $KUBECONFIG
       exit 0
   fi
   
   echo "I am a plugin named kubectl-foo"

After you install this plug-in for the {product-title} CLI, it can be invoked using the oc foo command.

Additional resources

• Review the Sample plug-in repository for an example of a plug-in written in Go.

• Review the CLI runtime repository for a set of utilities to assist in writing plug-ins in Go.