Chapter 3. Extending the CLI with plug-ins

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"

Procedure

1. If necessary, update the plug-in file to be executable.

   $ chmod +x <plugin_file>

2. Place the file anywhere in your PATH, such as /usr/local/bin/.

   $ sudo mv <plugin_file> /usr/local/bin/.

3. Run oc plugin list to make sure that the plug-in is listed.

   $ oc plugin list
   The following compatible plugins are available:
   
   /usr/local/bin/<plugin_file>

   If your plug-in is not listed here, verify that the file begins with oc- or kubectl-, is executable, and is on your PATH.

4. Invoke the new command or option introduced by the plug-in.

   For example, if you built and installed the kubectl-ns plug-in from the Sample plug-in repository, you can use the following command to view the current namespace.

   $ oc ns

   Note that the command to invoke the plug-in depends on the plug-in file name. For example, a plug-in with the file name of oc-foo-bar is invoked by the oc foo bar command.