WIP: implement maxSize alongside maxCapacity

WIP TBD

Signed-off-by: Francesco Romani <fromani@redhat.com>

Author: ffromani

pkg/pfpstatus/record/recorder.go

@@ -19,6 +19,7 @@ package record
 import (
 	"errors"
 	"time"
+	"unsafe"
 
 	"github.com/k8stopologyawareschedwg/podfingerprint"
 )
@@ -36,6 +37,28 @@ type RecordedStatus struct {
 	podfingerprint.Status
 	// RecordTime is a timestamp of when the RecordedStatus was added to the record
 	RecordTime time.Time `json:"recordTime"`
+	statusSize int       `json:"-"`
+}
+
+func cloneStatus(st podfingerprint.Status) (podfingerprint.Status, int) {
+	size := len(st.NodeName) + len(st.FingerprintExpected) + len(st.FingerprintComputed)
+	pods := make([]podfingerprint.NamespacedName, len(st.Pods))
+	for idx := 0; idx < len(st.Pods); idx++ {
+		pods[idx].Namespace = st.Pods[idx].Namespace
+		pods[idx].Name = st.Pods[idx].Name
+		size += len(pods[idx].Namespace) + len(pods[idx].Name)
+	}
+	ret := podfingerprint.Status{
+		FingerprintExpected: st.FingerprintExpected,
+		FingerprintComputed: st.FingerprintComputed,
+		Pods:                pods,
+		NodeName:            st.NodeName,
+	}
+	return ret, size
+}
+
+func (rs RecordedStatus) Size() int {
+	return rs.statusSize + int(unsafe.Sizeof(rs.RecordTime))
 }
 
 func (rs RecordedStatus) Equal(x RecordedStatus) bool {
@@ -51,32 +74,72 @@ type NodeRecorder struct {
 	timestamper func() time.Time
 	nodeName    string // shortcut
 	capacity    int
+	maxSize     int
+	size        int
 	statuses    []RecordedStatus
 }
 
+type NodeOption func(*NodeRecorder)
+
+func WithCapacity(capacity int) NodeOption {
+	return func(nr *NodeRecorder) {
+		nr.capacity = capacity
+	}
+}
+
+func WithMaxSize(maxSize int) NodeOption {
+	return func(nr *NodeRecorder) {
+		nr.maxSize = maxSize
+		nr.capacity = 1
+	}
+}
+
 // NewNodeRecorder creates a new recorder for the given node with the given capacity.
 // The record is a ring buffer, so only the latest <capacity> Statuses are kept at any time.
 // The timestamper callback is used to mark times. Use `time.Now` if unsure.
 // Returns the newly created instance; if parameters are incorrect, returns an error, on which
 // case the returned instance should be ignored.
-func NewNodeRecorder(nodeName string, capacity int, timestamper Timestamper) (*NodeRecorder, error) {
+func NewNodeRecorder(nodeName string, timestamper Timestamper, opts ...NodeOption) (*NodeRecorder, error) {
 	if nodeName == "" {
 		return nil, ErrMissingNode
 	}
-	if capacity < 1 {
-		return nil, ErrInvalidCapacity
-	}
 	nr := NodeRecorder{
 		timestamper: timestamper,
 		nodeName:    nodeName,
-		capacity:    capacity,
 	}
-	if capacity == 1 { // handle common special case
+	for _, opt := range opts {
+		opt(&nr)
+	}
+	if nr.capacity < 1 {
+		return nil, ErrInvalidCapacity
+	}
+	if nr.capacity == 1 { // handle common special case
 		nr.statuses = make([]RecordedStatus, 1)
 	}
 	return &nr, nil
 }
 
+func (nr *NodeRecorder) dropOldest() {
+	if nr.Len() < 1 {
+		return
+	}
+	nr.size -= nr.statuses[0].Size()
+	nr.statuses = nr.statuses[1:]
+}
+
+func (nr *NodeRecorder) makeRoom() {
+	if nr.capacity > 1 && nr.Len() == nr.Cap() {
+		nr.dropOldest()
+		return
+	}
+	if nr.maxSize == 0 {
+		return
+	}
+	for nr.size > nr.maxSize {
+		nr.dropOldest()
+	}
+}
+
 // Push adds a new Status to the record, evicting the oldest Status if necessary.
 // The pushed status is a full independent copy of the provided Status.
 // If the Status added is inconsistent, returns an error detailing the reason.
@@ -88,21 +151,21 @@ func (nr *NodeRecorder) Push(st podfingerprint.Status) error {
 	if st.NodeName != nr.nodeName {
 		return ErrMismatchingNode
 	}
+	ts := nr.timestamper()
+	cloned, size := cloneStatus(st)
+	item := RecordedStatus{
+		Status:     cloned,
+		RecordTime: ts,
+		statusSize: size,
+	}
 	if nr.capacity == 1 { // handle common special case, avoid any resize
-		nr.statuses[0] = RecordedStatus{
-			Status:     st.Clone(),
-			RecordTime: nr.timestamper(),
-		}
+		nr.statuses[0] = item
+		nr.size = item.Size()
 		return nil
 	}
-	if nr.Len() == nr.Cap() {
-		// drop the older sample
-		nr.statuses = nr.statuses[1:]
-	}
-	nr.statuses = append(nr.statuses, RecordedStatus{
-		Status:     st.Clone(),
-		RecordTime: nr.timestamper(),
-	})
+	nr.makeRoom()
+	nr.statuses = append(nr.statuses, item)
+	nr.size += item.Size()
 	return nil
 }
 
@@ -200,7 +263,7 @@ func (rr *Recorder) Push(st podfingerprint.Status) error {
 	var err error
 	nr, ok := rr.nodes[st.NodeName]
 	if !ok {
-		nr, err = NewNodeRecorder(st.NodeName, rr.nodeCapacity, rr.timestamper)
+		nr, err = NewNodeRecorder(st.NodeName, rr.timestamper, WithCapacity(rr.nodeCapacity))
 		if err != nil {
 			return err
 		}

pkg/pfpstatus/record/recorder_test.go

@@ -26,7 +26,7 @@ import (
 )
 
 func TestNodeRecorderCreate(t *testing.T) {
-	nr, err := NewNodeRecorder("test-node", 16, time.Now)
+	nr, err := NewNodeRecorder("test-node", time.Now, WithCapacity(16))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -40,7 +40,7 @@ func TestNodeRecorderCreate(t *testing.T) {
 }
 
 func TestNodeRecorderCreateInvalid(t *testing.T) {
-	_, err := NewNodeRecorder("test-node", 0, time.Now)
+	_, err := NewNodeRecorder("test-node", time.Now)
 	if err == nil {
 		t.Fatalf("unexpected success")
 	}
@@ -50,7 +50,7 @@ func TestNodeRecorderCreateInvalid(t *testing.T) {
 }
 
 func TestNodeRecorderPushMissingNodeName(t *testing.T) {
-	nr, err := NewNodeRecorder("test-node", 16, time.Now)
+	nr, err := NewNodeRecorder("test-node", time.Now, WithCapacity(16))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -66,7 +66,7 @@ func TestNodeRecorderPushMissingNodeName(t *testing.T) {
 }
 
 func TestNodeRecorderPushMismatchingNodeName(t *testing.T) {
-	nr, err := NewNodeRecorder("test-node", 16, time.Now)
+	nr, err := NewNodeRecorder("test-node", time.Now, WithCapacity(16))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -82,7 +82,7 @@ func TestNodeRecorderPushMismatchingNodeName(t *testing.T) {
 }
 
 func TestNodeRecorderPushBasic(t *testing.T) {
-	nr, err := NewNodeRecorder("test-node", 16, time.Now)
+	nr, err := NewNodeRecorder("test-node", time.Now, WithCapacity(16))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -98,7 +98,7 @@ func TestNodeRecorderPushBasic(t *testing.T) {
 }
 
 func TestNodeRecorderSingleEntryPushEvict(t *testing.T) {
-	nr, err := NewNodeRecorder("test-node", 1, time.Now)
+	nr, err := NewNodeRecorder("test-node", time.Now, WithCapacity(1))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -132,7 +132,7 @@ func TestNodeRecorderSingleEntryPushEvict(t *testing.T) {
 }
 
 func TestNodeRecorderMultiEntryPushContentEvict(t *testing.T) {
-	nr, err := NewNodeRecorder("test-node", 3, time.Now)
+	nr, err := NewNodeRecorder("test-node", time.Now, WithCapacity(3))
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}