rebase: update kubernetes to v1.23.0

updating go dependency to latest kubernetes
released version i.e v1.23.0

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

vendor/sigs.k8s.io/controller-runtime/pkg/manager/runnable_group.go

@@ -0,0 +1,296 @@
+package manager
+
+import (
+	"context"
+	"errors"
+	"sync"
+
+	"sigs.k8s.io/controller-runtime/pkg/webhook"
+)
+
+var (
+	errRunnableGroupStopped = errors.New("can't accept new runnable as stop procedure is already engaged")
+)
+
+// readyRunnable encapsulates a runnable with
+// a ready check.
+type readyRunnable struct {
+	Runnable
+	Check       runnableCheck
+	signalReady bool
+}
+
+// runnableCheck can be passed to Add() to let the runnable group determine that a
+// runnable is ready. A runnable check should block until a runnable is ready,
+// if the returned result is false, the runnable is considered not ready and failed.
+type runnableCheck func(ctx context.Context) bool
+
+// runnables handles all the runnables for a manager by grouping them accordingly to their
+// type (webhooks, caches etc.).
+type runnables struct {
+	Webhooks       *runnableGroup
+	Caches         *runnableGroup
+	LeaderElection *runnableGroup
+	Others         *runnableGroup
+}
+
+// newRunnables creates a new runnables object.
+func newRunnables(errChan chan error) *runnables {
+	return &runnables{
+		Webhooks:       newRunnableGroup(errChan),
+		Caches:         newRunnableGroup(errChan),
+		LeaderElection: newRunnableGroup(errChan),
+		Others:         newRunnableGroup(errChan),
+	}
+}
+
+// Add adds a runnable to closest group of runnable that they belong to.
+//
+// Add should be able to be called before and after Start, but not after StopAndWait.
+// Add should return an error when called during StopAndWait.
+// The runnables added before Start are started when Start is called.
+// The runnables added after Start are started directly.
+func (r *runnables) Add(fn Runnable) error {
+	switch runnable := fn.(type) {
+	case hasCache:
+		return r.Caches.Add(fn, func(ctx context.Context) bool {
+			return runnable.GetCache().WaitForCacheSync(ctx)
+		})
+	case *webhook.Server:
+		return r.Webhooks.Add(fn, nil)
+	case LeaderElectionRunnable:
+		if !runnable.NeedLeaderElection() {
+			return r.Others.Add(fn, nil)
+		}
+		return r.LeaderElection.Add(fn, nil)
+	default:
+		return r.LeaderElection.Add(fn, nil)
+	}
+}
+
+// runnableGroup manages a group of runnables that are
+// meant to be running together until StopAndWait is called.
+//
+// Runnables can be added to a group after the group has started
+// but not after it's stopped or while shutting down.
+type runnableGroup struct {
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	start        sync.Mutex
+	startOnce    sync.Once
+	started      bool
+	startQueue   []*readyRunnable
+	startReadyCh chan *readyRunnable
+
+	stop     sync.RWMutex
+	stopOnce sync.Once
+	stopped  bool
+
+	// errChan is the error channel passed by the caller
+	// when the group is created.
+	// All errors are forwarded to this channel once they occur.
+	errChan chan error
+
+	// ch is the internal channel where the runnables are read off from.
+	ch chan *readyRunnable
+
+	// wg is an internal sync.WaitGroup that allows us to properly stop
+	// and wait for all the runnables to finish before returning.
+	wg *sync.WaitGroup
+}
+
+func newRunnableGroup(errChan chan error) *runnableGroup {
+	r := &runnableGroup{
+		startReadyCh: make(chan *readyRunnable),
+		errChan:      errChan,
+		ch:           make(chan *readyRunnable),
+		wg:           new(sync.WaitGroup),
+	}
+	r.ctx, r.cancel = context.WithCancel(context.Background())
+	return r
+}
+
+// Started returns true if the group has started.
+func (r *runnableGroup) Started() bool {
+	r.start.Lock()
+	defer r.start.Unlock()
+	return r.started
+}
+
+// Start starts the group and waits for all
+// initially registered runnables to start.
+// It can only be called once, subsequent calls have no effect.
+func (r *runnableGroup) Start(ctx context.Context) error {
+	var retErr error
+
+	r.startOnce.Do(func() {
+		defer close(r.startReadyCh)
+
+		// Start the internal reconciler.
+		go r.reconcile()
+
+		// Start the group and queue up all
+		// the runnables that were added prior.
+		r.start.Lock()
+		r.started = true
+		for _, rn := range r.startQueue {
+			rn.signalReady = true
+			r.ch <- rn
+		}
+		r.start.Unlock()
+
+		// If we don't have any queue, return.
+		if len(r.startQueue) == 0 {
+			return
+		}
+
+		// Wait for all runnables to signal.
+		for {
+			select {
+			case <-ctx.Done():
+				if err := ctx.Err(); !errors.Is(err, context.Canceled) {
+					retErr = err
+				}
+			case rn := <-r.startReadyCh:
+				for i, existing := range r.startQueue {
+					if existing == rn {
+						// Remove the item from the start queue.
+						r.startQueue = append(r.startQueue[:i], r.startQueue[i+1:]...)
+						break
+					}
+				}
+				// We're done waiting if the queue is empty, return.
+				if len(r.startQueue) == 0 {
+					return
+				}
+			}
+		}
+	})
+
+	return retErr
+}
+
+// reconcile is our main entrypoint for every runnable added
+// to this group. Its primary job is to read off the internal channel
+// and schedule runnables while tracking their state.
+func (r *runnableGroup) reconcile() {
+	for runnable := range r.ch {
+		// Handle stop.
+		// If the shutdown has been called we want to avoid
+		// adding new goroutines to the WaitGroup because Wait()
+		// panics if Add() is called after it.
+		{
+			r.stop.RLock()
+			if r.stopped {
+				// Drop any runnables if we're stopped.
+				r.errChan <- errRunnableGroupStopped
+				r.stop.RUnlock()
+				continue
+			}
+
+			// Why is this here?
+			// When StopAndWait is called, if a runnable is in the process
+			// of being added, we could end up in a situation where
+			// the WaitGroup is incremented while StopAndWait has called Wait(),
+			// which would result in a panic.
+			r.wg.Add(1)
+			r.stop.RUnlock()
+		}
+
+		// Start the runnable.
+		go func(rn *readyRunnable) {
+			go func() {
+				if rn.Check(r.ctx) {
+					if rn.signalReady {
+						r.startReadyCh <- rn
+					}
+				}
+			}()
+
+			// If we return, the runnable ended cleanly
+			// or returned an error to the channel.
+			//
+			// We should always decrement the WaitGroup here.
+			defer r.wg.Done()
+
+			// Start the runnable.
+			if err := rn.Start(r.ctx); err != nil {
+				r.errChan <- err
+			}
+		}(runnable)
+	}
+}
+
+// Add should be able to be called before and after Start, but not after StopAndWait.
+// Add should return an error when called during StopAndWait.
+func (r *runnableGroup) Add(rn Runnable, ready runnableCheck) error {
+	r.stop.RLock()
+	if r.stopped {
+		r.stop.RUnlock()
+		return errRunnableGroupStopped
+	}
+	r.stop.RUnlock()
+
+	if ready == nil {
+		ready = func(_ context.Context) bool { return true }
+	}
+
+	readyRunnable := &readyRunnable{
+		Runnable: rn,
+		Check:    ready,
+	}
+
+	// Handle start.
+	// If the overall runnable group isn't started yet
+	// we want to buffer the runnables and let Start()
+	// queue them up again later.
+	{
+		r.start.Lock()
+
+		// Check if we're already started.
+		if !r.started {
+			// Store the runnable in the internal if not.
+			r.startQueue = append(r.startQueue, readyRunnable)
+			r.start.Unlock()
+			return nil
+		}
+		r.start.Unlock()
+	}
+
+	// Enqueue the runnable.
+	r.ch <- readyRunnable
+	return nil
+}
+
+// StopAndWait waits for all the runnables to finish before returning.
+func (r *runnableGroup) StopAndWait(ctx context.Context) {
+	r.stopOnce.Do(func() {
+		// Close the reconciler channel once we're done.
+		defer close(r.ch)
+
+		_ = r.Start(ctx)
+		r.stop.Lock()
+		// Store the stopped variable so we don't accept any new
+		// runnables for the time being.
+		r.stopped = true
+		r.stop.Unlock()
+
+		// Cancel the internal channel.
+		r.cancel()
+
+		done := make(chan struct{})
+		go func() {
+			defer close(done)
+			// Wait for all the runnables to finish.
+			r.wg.Wait()
+		}()
+
+		select {
+		case <-done:
+			// We're done, exit.
+		case <-ctx.Done():
+			// Calling context has expired, exit.
+		}
+	})
+}