Implement suspend, resume, reconcile image-update

.. and refactor. These are all amenable to the adapter refactoring
that has served well so far.

Signed-off-by: Michael Bridgen <michael@weave.works>

cmd/flux/suspend.go

@@ -17,7 +17,13 @@ limitations under the License.
 package main
 
 import (
+	"context"
+	"fmt"
+
 	"github.com/spf13/cobra"
+	"k8s.io/apimachinery/pkg/types"
+
+	"github.com/fluxcd/flux2/internal/utils"
 )
 
 var suspendCmd = &cobra.Command{
@@ -29,3 +35,47 @@ var suspendCmd = &cobra.Command{
 func init() {
 	rootCmd.AddCommand(suspendCmd)
 }
+
+type suspendable interface {
+	adapter
+	isSuspended() bool
+	setSuspended()
+}
+
+type suspendCommand struct {
+	object    suspendable
+	humanKind string
+}
+
+func (suspend suspendCommand) run(cmd *cobra.Command, args []string) error {
+	if len(args) < 1 {
+		return fmt.Errorf("%s name is required", suspend.humanKind)
+	}
+	name := args[0]
+
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	kubeClient, err := utils.KubeClient(kubeconfig, kubecontext)
+	if err != nil {
+		return err
+	}
+
+	namespacedName := types.NamespacedName{
+		Namespace: namespace,
+		Name:      name,
+	}
+	err = kubeClient.Get(ctx, namespacedName, suspend.object.asRuntimeObject())
+	if err != nil {
+		return err
+	}
+
+	logger.Actionf("suspending %s %s in %s namespace", suspend.humanKind, name, namespace)
+	suspend.object.setSuspended()
+	if err := kubeClient.Update(ctx, suspend.object.asRuntimeObject()); err != nil {
+		return err
+	}
+	logger.Successf("%s suspended", suspend.humanKind)
+
+	return nil
+}