postdeploy-hooks/k8s-cleanup/main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"regexp"

	"cloud.google.com/go/storage"
)

var (
	namespace = flag.String("namespace", "", "Namespace(s) to filter on when finding resources to delete. "+
		"For multiple namespaces, separate them with a comma. For example --namespace=foo,bar. By default "+
		"resources will be deleted across all namespaces.")
	resourceType = flag.String("resource-type",
		"service,cronjob.batch,job.batch,deployment.apps,statefulset.apps,pod,configmap,secret,horizontalpodautoscaler.autoscaling",
		"Comma separated list of resource type(s) to filter on when finding "+
			"resources to delete. See default list above of resources that will"+
			"be deleted. To have ALL resources deleted pass in \"all\". "+
			"You can also qualify the resource type by an API group if you want"+
			"to specify resources only in a specific API group. For example --resource-type=deployments.apps")
)

// gkeClusterRegex represents the regex that a GKE cluster resource name needs to match.
var gkeClusterRegex = regexp.MustCompile("^projects/([^/]+)/locations/([^/]+)/clusters/([^/]+)$")

const (
	// The name of the postdeploy hook cleanup sample, this is passed back to
	// Cloud Deploy as metadata in the deploy results.
	cleanupSampleName         = "clouddeploy-k8s-cleanup-sample"
	postdeployHookMetadataKey = "postdeploy-hook-source"
)

func main() {
	flag.Parse()

	// Print the value of the command-line flags to aid debugging.
	fmt.Printf("Value of resource-type command-line flag: %s\n", *resourceType)
	fmt.Printf("Value of namespace command-line flag: %s \n", *namespace)

	if err := do(); err != nil {
		fmt.Printf("err: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("Done!")
	os.Exit(0)
}

func do() error {
	// Step 1. Run gcloud get-credentials to set up the cluster credentials.
	gkeCluster := os.Getenv("GKE_CLUSTER")
	if err := gcloudClusterCredentials(gkeCluster); err != nil {
		return err
	}

	// Step 2. Get a list of resources to delete.
	kubectlExec := CreateCommandExecutor("kubectl")
	oldResources, err := kubectlExec.resourcesToDelete(*namespace, *resourceType)
	if err != nil {
		return err
	}

	// Step 3. Delete the resources.
	if err := kubectlExec.deleteResources(oldResources); err != nil {
		return err
	}

	// Step 4. Upload metadata.
	ctx := context.Background()
	deployHookResult := &postdeployHookResult{
		Metadata: map[string]string{
			postdeployHookMetadataKey: cleanupSampleName,
		},
	}
	gcsClient, err := storage.NewClient(ctx)
	if err != nil {
		return fmt.Errorf("unable to create cloud storage client: %v", err)
	}
	if err := uploadResult(ctx, gcsClient, deployHookResult); err != nil {
		return err
	}

	return nil
}

// gcloudClusterCredentials runs `gcloud container clusters get-crendetials` to set up
// the cluster credentials.
func gcloudClusterCredentials(gkeCluster string) error {
	gcloudExec := CreateCommandExecutor("gcloud")
	m := gkeClusterRegex.FindStringSubmatch(gkeCluster)
	if len(m) == 0 {
		return fmt.Errorf("invalid GKE cluster name: %s", gkeCluster)
	}

	args := []string{"container", "clusters", "get-credentials", m[3], fmt.Sprintf("--region=%s", m[2]), fmt.Sprintf("--project=%s", m[1])}
	_, err := gcloudExec.execCommand(args)
	if err != nil {
		return fmt.Errorf("unable to set up cluster credentials: %w", err)
	}
	return nil
}