How to create a Plugin

    This section will walk you through a basic plugin development.

    Types

    If you are using Typescript for developing the plugin, the @kinvolk/headlamp-plugin package does ship some type declarations in @kinvolk/headlamp-plugin/types. Please notice that the whole external plugin mechanics are still in an early development phase and thus only the actual type declarations (and not the corresponding code) is shipped in this package at the moment.

    Hello Kubernetes

    The following example will show a basic plugin declaration and registration in a file that should match the src/index.tsx structure explained in the building section.

    import { registerAppBarAction } from '@kinvolk/headlamp-plugin/lib';
    registerAppBarAction(<span>Hello Kubernetes</span>);
    

    Plugin Example

    Let’s create a plugin that just gets the number of pods in the cluster and displays that information in the top bar (i.e. registers an “app bar action”).

    import { K8s, registerAppBarAction } from '@kinvolk/headlamp-plugin/lib';
    import { Typography } from '@mui/material';
    
    function PodCounter() {
      const [pods, error] = K8s.ResourceClasses.Pod.useList();
      const msg = pods === null ? 'Loading…' : pods.length.toString();
    
      return (
        <Typography color="textPrimary" sx={{fontStyle: 'italic'}}>
          {!error ? `# Pods: ${msg}` : 'Uh, pods!?'}
        </Typography>
      );
    }
    
    registerAppBarAction(<PodCounter />);
    

    Here is the result, running Headlamp with this plugin and using with a Minikube cluster:

    screenshot showing a label on the top bar with the number of pods available

    Please refer to the functionality section for learning about the different functionality that is available to plugins by the registry.