Make Full ListOptions Available

Create an alternate constructor that allows us to set all the fields of
the ListOptions so we can filter on Fields as well as Labels.  Also,
delegate to the new, more flexible, constructor from the old one.

k8s_pod_watcher.go

@@ -174,7 +174,7 @@ func (i *InitialListComplete) Continues() bool {
 type PodWatcher struct {
 	cs           kubernetes.Interface
 	k8sNamespace string
-	selector     string
+	listOpts     k8smeta.ListOptions
 
 	cbs []EventCallback
 
@@ -189,13 +189,14 @@ type Logger interface {
 	Printf(string, ...interface{})
 }
 
-// NewPodWatcher constructs a new PodWatcher. Each callback in the variadic
-// callback list is called in its own goroutine.
-func NewPodWatcher(cs kubernetes.Interface, k8sNamespace, selector string, cbs ...EventCallback) *PodWatcher {
+// NewPodWatcherOptions constructs a new PodWatcher with a potentially more
+// complicated selector. Each callback in the variadic callback list is called
+// in its own goroutine.
+func NewPodWatcherOptions(cs kubernetes.Interface, k8sNamespace string, options k8smeta.ListOptions, cbs ...EventCallback) *PodWatcher {
 	return &PodWatcher{
 		cs:           cs,
 		k8sNamespace: k8sNamespace,
-		selector:     selector,
+		listOpts:     options,
 		cbs:          cbs,
 		tracker: podTracker{
 			lastStatus:  map[string]*k8score.Pod{},
@@ -204,17 +205,20 @@ func NewPodWatcher(cs kubernetes.Interface, k8sNamespace, selector string, cbs .
 	}
 }
 
+// NewPodWatcher constructs a new PodWatcher. The `selector` selects by labels
+// only.  Each callback in the variadic callback list is called in its own
+// goroutine.
+func NewPodWatcher(cs kubernetes.Interface, k8sNamespace, selector string, cbs ...EventCallback) *PodWatcher {
+	return NewPodWatcherOptions(cs, k8sNamespace, k8smeta.ListOptions{LabelSelector: selector}, cbs...)
+}
+
 func (p *PodWatcher) logf(format string, args ...interface{}) {
 	if p.Logger == nil {
 		return
 	}
 	p.Logger.Printf(format, args...)
 }
 
-func (p *PodWatcher) listOpts() k8smeta.ListOptions {
-	return k8smeta.ListOptions{LabelSelector: p.selector}
-}
-
 func setContinues(ev PodEvent, continues bool) {
 	switch pe := ev.(type) {
 	case *CreatePod:
@@ -231,7 +235,7 @@ func setContinues(ev PodEvent, continues bool) {
 // returns the new version ID (or an error)
 func (p *PodWatcher) resync(ctx context.Context, cbChans []chan<- PodEvent) (string, error) {
 	initPods, initListerr := p.cs.CoreV1().Pods(p.k8sNamespace).List(
-		ctx, p.listOpts())
+		ctx, p.listOpts)
 	if initListerr != nil {
 		return "", fmt.Errorf("failed pod listing: %w", initListerr)
 	}
@@ -278,7 +282,7 @@ func (p *PodWatcher) resync(ctx context.Context, cbChans []chan<- PodEvent) (str
 // returns the number of pods, resource version and (optionally) an error
 func (p *PodWatcher) initialPods(ctx context.Context) (int, string, error) {
 	initPods, initListerr := p.cs.CoreV1().Pods(p.k8sNamespace).List(
-		ctx, p.listOpts())
+		ctx, p.listOpts)
 	if initListerr != nil {
 		return -1, "", fmt.Errorf("failed initial pod listing: %w", initListerr)
 	}
@@ -391,7 +395,7 @@ func (p *PodWatcher) Run(ctx context.Context) error {
 
 	lastwatchStart := time.Now()
 	for {
-		watchOpt := p.listOpts()
+		watchOpt := p.listOpts
 		watchOpt.ResourceVersion = version
 		podWatch, watchStartErr := p.cs.CoreV1().Pods(p.k8sNamespace).Watch(ctx, watchOpt)
 		if watchStartErr != nil {