mock cache-service oplog truncation functionality

render-2023-10-11/cmd/cache-service/oplog.go

@@ -7,7 +7,9 @@ import (
 )
 
 type Oplog struct {
-	events []timestampedEvent
+	events        []timestampedEvent
+	idx           int // todo
+	lastTruncated time.Time
 }
 
 type timestampedEvent struct {
@@ -34,7 +36,11 @@ func (oplog *Oplog) push(t time.Time, event thestore.Event) {
 	})
 }
 
-func (oplog *Oplog) Since(t time.Time) []thestore.Event {
+func (oplog *Oplog) Since(t time.Time) ([]thestore.Event, bool) {
+	if !t.After(oplog.lastTruncated) {
+		return nil, false
+	}
+
 	result := make([]thestore.Event, 0, 5)
 	for i := len(oplog.events) - 1; i >= 0; i-- {
 		if !oplog.events[i].t.After(t) {
@@ -43,5 +49,5 @@ func (oplog *Oplog) Since(t time.Time) []thestore.Event {
 		result = append(result, oplog.events[i].e)
 	}
 	slices.Reverse(result)
-	return result
+	return result, len(result) > 0
 }

render-2023-10-11/cmd/cache-service/oplog_test.go

@@ -13,7 +13,7 @@ func TestOplog(t *testing.T) {
 	oplog.push(time.Unix(3, 0), thestore.Event{ID: "3"})
 	oplog.push(time.Unix(4, 0), thestore.Event{ID: "4"})
 
-	got := oplog.Since(time.Unix(2, 0))
+	got, _ := oplog.Since(time.Unix(2, 0))
 	if len(got) != 2 {
 		t.Error(got)
 	} else if got[0].ID != "3" {

render-2023-10-11/cmd/cache-service/server.go

@@ -56,10 +56,13 @@ func (server Server) serveGetEvents(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		// todo emit helpful err message
 		w.WriteHeader(http.StatusBadRequest)
-		return nil
+		return
 	}
 	since := time.Unix(sinceInt, 0)
 
-	result := server.oplog.Since(since)
+	result, ok := server.oplog.Since(since)
+	if !ok {
+		result = server.store.Dump()
+	}
 	json.NewEncoder(w).Encode(result)
 }

render-2023-10-11/internal/thestore/store.go

@@ -10,6 +10,16 @@ func NewStore() *Store {
 	return &store
 }
 
+// todo pass context.context and failfast
+func (store *Store) Dump() []Event {
+	result := make([]Event, 0)
+	(*sync.Map)(store).Range(func(_, v any) bool {
+		result = append(result, v.(Event))
+		return true
+	})
+	return result
+}
+
 func (store *Store) Push(op Event) {
 	k := op.ID
 	event, ok := store.Get(k)