Add kubernetes-based backend (#250)

Signed-off-by: Micah Hausler <[email protected]>

## Description

The new backend uses the Kubernetes CRD types in Tinkerbell core. Boots could use a bit of a refactor/organization in how the backends work, but for now I've tried to fit in to the existing structure. 

## Why is this needed

This is the boots side of work for tinkerbell/proposals#46

Fixes: #

## How Has This Been Tested?

Tested with real bare metal workers using an image built from this branch. I will add E2E tests in a follow up PR, or can add to this branch

## How are existing users impacted? What migration steps/scripts do we need?

No impact to existing users

## Checklist:

I have:

- [ ] updated the documentation and/or roadmap (if required)
- [ ] added unit or e2e tests
- [ ] provided instructions on how to upgrade

client/kubernetes/cluster.go

@@ -0,0 +1,135 @@
+package kubernetes
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/tinkerbell/tink/pkg/apis/core/v1alpha1"
+	"k8s.io/apimachinery/pkg/runtime"
+	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
+	"k8s.io/client-go/rest"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/cluster"
+)
+
+const (
+	WorkflowWorkerNonTerminalStateIndex = ".status.state.nonTerminalWorker"
+	HardwareMACAddrIndex                = ".spec.interfaces.dhcp.mac"
+	HardwareIPAddrIndex                 = ".spec.interfaces.dhcp.ip"
+)
+
+// NewCluster returns a controller-runtime cluster.Cluster with the Tinkerbell runtime
+// scheme registered, and indexers for:
+// * Hardware by MAC address
+// * Hardware by IP address
+// * Workflows by worker address
+//
+// Callers must instantiate the client-side cache by calling Start() before use.
+func NewCluster(config *rest.Config) (cluster.Cluster, error) {
+	runtimescheme := runtime.NewScheme()
+
+	err := clientgoscheme.AddToScheme(runtimescheme)
+	if err != nil {
+		return nil, err
+	}
+
+	err = v1alpha1.AddToScheme(runtimescheme)
+	if err != nil {
+		return nil, err
+	}
+
+	c, err := cluster.New(config, func(o *cluster.Options) {
+		o.Scheme = runtimescheme
+	})
+
+	if err != nil {
+		return nil, err
+	}
+	indexers := []struct {
+		obj          client.Object
+		field        string
+		extractValue client.IndexerFunc
+	}{
+		{
+			&v1alpha1.Workflow{},
+			WorkflowWorkerNonTerminalStateIndex,
+			workflowWorkerNonTerminalStateIndexFunc,
+		},
+		{
+			&v1alpha1.Hardware{},
+			HardwareIPAddrIndex,
+			hardwareIPIndexFunc,
+		},
+		{
+			&v1alpha1.Hardware{},
+			HardwareMACAddrIndex,
+			hardwareMacIndexFunc,
+		},
+	}
+	for _, indexer := range indexers {
+		if err := c.GetFieldIndexer().IndexField(
+			context.Background(),
+			indexer.obj,
+			indexer.field,
+			indexer.extractValue,
+		); err != nil {
+			return nil, fmt.Errorf("failed to setup %s indexer, %w", indexer.field, err)
+		}
+	}
+
+	return c, nil
+}
+
+// TODO micahhausler: make the following index functions public in tinkerbell/tink import from there
+
+// workflowWorkerNonTerminalStateIndexFunc func indexes workflow by worker for non terminal workflows.
+func workflowWorkerNonTerminalStateIndexFunc(obj client.Object) []string {
+	wf, ok := obj.(*v1alpha1.Workflow)
+	if !ok {
+		return nil
+	}
+
+	resp := []string{}
+	if !(wf.Status.State == v1alpha1.WorkflowStateRunning || wf.Status.State == v1alpha1.WorkflowStatePending) {
+		return resp
+	}
+	for _, task := range wf.Status.Tasks {
+		if task.WorkerAddr != "" {
+			resp = append(resp, task.WorkerAddr)
+		}
+	}
+
+	return resp
+}
+
+// hardwareMacIndexFunc returns a list of mac addresses from a hardware.
+func hardwareMacIndexFunc(obj client.Object) []string {
+	hw, ok := obj.(*v1alpha1.Hardware)
+	if !ok {
+		return nil
+	}
+	resp := []string{}
+	for _, iface := range hw.Spec.Interfaces {
+		if iface.DHCP != nil && iface.DHCP.MAC != "" {
+			resp = append(resp, iface.DHCP.MAC)
+		}
+	}
+
+	return resp
+}
+
+// hardwareIPIndexFunc returns a list of mac addresses from a hardware.
+func hardwareIPIndexFunc(obj client.Object) []string {
+	hw, ok := obj.(*v1alpha1.Hardware)
+	if !ok {
+		return nil
+	}
+	resp := []string{}
+	for _, iface := range hw.Spec.Interfaces {
+		if iface.DHCP != nil && iface.DHCP.IP != nil && iface.DHCP.IP.Address != "" {
+			resp = append(resp, iface.DHCP.IP.Address)
+		}
+	}
+
+	return resp
+}

client/kubernetes/hardware_finder.go

@@ -0,0 +1,137 @@
+package kubernetes
+
+import (
+	"context"
+	"net"
+
+	"github.com/packethost/pkg/log"
+	"github.com/pkg/errors"
+	"github.com/tinkerbell/boots/client"
+	"github.com/tinkerbell/tink/pkg/apis/core/v1alpha1"
+	"github.com/tinkerbell/tink/pkg/controllers"
+	"github.com/tinkerbell/tink/pkg/convert"
+	"github.com/tinkerbell/tink/protos/workflow"
+	"k8s.io/client-go/tools/clientcmd"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
+	crclient "sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+// Finder is a type that looks up hardware and workflows from Kubernetes
+type Finder struct {
+	clientFunc   func() crclient.Client
+	cacheStarter func(context.Context) error
+	logger       log.Logger
+	namespace    string
+}
+
+// NewFinder returns a HardwareFinder that discovers hardware from Kubernetes.
+//
+// Callers must instantiate the client-side cache by calling Start() before use.
+func NewFinder(logger log.Logger, k8sAPI, kubeconfig string) (*Finder, error) {
+	ccfg := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
+		&clientcmd.ClientConfigLoadingRules{ExplicitPath: kubeconfig},
+		&clientcmd.ConfigOverrides{ClusterInfo: clientcmdapi.Cluster{Server: k8sAPI}})
+
+	config, err := ccfg.ClientConfig()
+	if err != nil {
+		return nil, err
+	}
+
+	namespace, _, err := ccfg.Namespace()
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	cluster, err := NewCluster(config)
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return &Finder{
+		clientFunc:   cluster.GetClient,
+		cacheStarter: cluster.Start,
+		logger:       logger,
+		namespace:    namespace,
+	}, nil
+}
+
+// Start instantiates the client-side cache
+func (f *Finder) Start(ctx context.Context) error {
+	return f.cacheStarter(ctx)
+}
+
+// ByIP returns a Discoverer for a particular IP.
+func (f *Finder) ByIP(ctx context.Context, ip net.IP) (client.Discoverer, error) {
+	hardwareList := &v1alpha1.HardwareList{}
+
+	err := f.clientFunc().List(ctx, hardwareList, &crclient.MatchingFields{
+		controllers.HardwareIPAddrIndex: ip.String(),
+	})
+	if err != nil {
+		return nil, errors.Wrap(err, "failed listing hardware")
+	}
+
+	if len(hardwareList.Items) == 0 {
+		return nil, errors.New("no hardware found")
+	}
+
+	if len(hardwareList.Items) > 1 {
+		return nil, errors.Errorf("got %d hardware for ip %s, expected only 1", len(hardwareList.Items), ip)
+	}
+
+	return NewK8sDiscoverer(&hardwareList.Items[0]), nil
+}
+
+// ByMAC returns a Discoverer for a particular MAC address.
+func (f *Finder) ByMAC(ctx context.Context, mac net.HardwareAddr, _ net.IP, _ string) (client.Discoverer, error) {
+	hardwareList := &v1alpha1.HardwareList{}
+
+	err := f.clientFunc().List(ctx, hardwareList, &crclient.MatchingFields{
+		controllers.HardwareMACAddrIndex: mac.String(),
+	})
+	if err != nil {
+		return nil, errors.Wrap(err, "failed listing hardware")
+	}
+
+	if len(hardwareList.Items) == 0 {
+		return nil, errors.New("no hardware found")
+	}
+
+	if len(hardwareList.Items) > 1 {
+		return nil, errors.Errorf("got %d hardware for mac %s, expected only 1", len(hardwareList.Items), mac)
+	}
+
+	return NewK8sDiscoverer(&hardwareList.Items[0]), nil
+}
+
+// HasActiveWorkflow finds if an active workflow exists for a particular hardware ID.
+func (f *Finder) HasActiveWorkflow(ctx context.Context, hwID client.HardwareID) (bool, error) {
+	if hwID == "" {
+		return false, errors.New("missing hardware id")
+	}
+
+	stored := &v1alpha1.WorkflowList{}
+	err := f.clientFunc().List(ctx, stored, &crclient.MatchingFields{
+		controllers.WorkflowWorkerNonTerminalStateIndex: hwID.String(),
+	})
+	if err != nil {
+		return false, errors.Wrap(err, "failed to list workflows")
+	}
+
+	wfContexts := []*workflow.WorkflowContext{}
+	for _, wf := range stored.Items {
+		wfContexts = append(wfContexts, convert.WorkflowToWorkflowContext(&wf))
+	}
+
+	wcl := &workflow.WorkflowContextList{
+		WorkflowContexts: wfContexts,
+	}
+
+	for _, wf := range (*wcl).WorkflowContexts {
+		if wf.CurrentActionState == workflow.State_STATE_PENDING || wf.CurrentActionState == workflow.State_STATE_RUNNING {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}