k8s-utility-client

K8s Utility Client

A library creating a set of Kubernetes clients - both standard and dynamic that can be used within a K8s cluster, or without.

The Operator Framework makes a k8s client that is insufficient to generating a Dynamic client, so I put this together to make all the clients I need.

It works the same whether it's running inside a cluster or without. I don't have to care.

Sometimes you just want things to just work.

Usage

Creating a Client

Creating a clientis easy. Just use:

    client, err := NewK8sClients()
    if err != nil {
        log.Fatalf("failed creating client: %s", err)
    }

It will look for your config file in ~/.kube/config. The dynamic client must be able to reach a k8s cluster in order to do it's thing.

Loading Resource Files

To load the files, run

    interfaces, objects, err := client.ResourcesAndObjectsFromFile(fileName)
    if err != nil {
        log.Fatalf("failed to load yaml file %s: %s", fileName, err)
    }

Applying Resources

The ApplyResources() method is smart enough to Create or Update, depending on whether the resources being applied already exist or not.

    ctx := context.TODO()

    fmt.Printf("Creating resources in k8s.\n")
    err = client.ApplyResources(ctx, interfaces, objects)
    if err != nil {
        t.Errorf("failed to apply resources: %s", err)
    }

Getting Resources

To Get and examine resources, use the 'objects' and 'interfaces' returned by loading:

    fmt.Printf("Verifying resources in k8s.\n")
    for i, obj := range objects {
        ri := interfaces[i]

        o, err := ri.Get(ctx, obj.GetName(), metav1.GetOptions{})
        if err != nil {
            t.Errorf("failed getting resource %s kind %s", obj.GetName(), obj.GetKind())
        }

        assert.Equal(t, obj.GetName(), o.GetName(), "Created Resource name doesn't match expectation.")
        assert.Equal(t, obj.GetKind(), o.GetKind(), "Created Resource Kind does not match expectations.")
        assert.Equal(t, obj.GetNamespace(), o.GetNamespace(), "Created Resource Namespace does not match expectations.")

    }

Deleting Resources

To clean up, call DeleteResources()

    ctx := context.TODO()

    fmt.Printf("Cleaning up resources in k8s.\n")
    err = client.DeleteResources(ctx, interfaces, objects)
    if err != nil {
        t.Errorf("failed deleting resources: %s", err)
    }