Event-handler: call SearchUnstructuredEvents with smaller windows

This PR aims to reduce the windows sent from `SearchUnstructuredEvents`.
StartTime is never update so it's kept with its initial value which
causes problems to the event handler sending windows that include more
than 1Gb of data when using the Athena backend which causes failures.

Signed-off-by: Tiago Silva <[email protected]>

event-handler/app.go

@@ -179,7 +179,7 @@ func (a *App) init(ctx context.Context) error {
 		return trace.Wrap(err)
 	}
 
-	t, err := NewTeleportEventsWatcher(ctx, a.Config, *startTime, latestCursor, latestID)
+	t, err := NewTeleportEventsWatcher(ctx, a.Config, *startTime, latestCursor, latestID, s)
 	if err != nil {
 		return trace.Wrap(err)
 	}

event-handler/teleport_events_watcher.go

@@ -71,6 +71,7 @@ type TeleportEventsWatcher struct {
 	config *StartCmdConfig
 	// startTime is event time frame start
 	startTime time.Time
+	state     *State
 }
 
 // NewTeleportEventsWatcher builds Teleport client instance
@@ -80,6 +81,7 @@ func NewTeleportEventsWatcher(
 	startTime time.Time,
 	cursor string,
 	id string,
+	state *State,
 ) (*TeleportEventsWatcher, error) {
 	var creds []client.Credentials
 	switch {
@@ -207,16 +209,49 @@ func (t *TeleportEventsWatcher) fetch(ctx context.Context) error {
 
 // getEvents calls Teleport client and loads events
 func (t *TeleportEventsWatcher) getEvents(ctx context.Context) ([]*auditlogpb.EventUnstructured, string, error) {
-	return t.client.SearchUnstructuredEvents(
-		ctx,
-		t.startTime,
-		time.Now().UTC(),
-		"default",
-		t.config.Types,
-		t.config.BatchSize,
-		types.EventOrderAscending,
-		t.cursor,
-	)
+	rangeSplitByDay := splitRangeByDay(t.startTime, time.Now().UTC())
+	for i := 1; i < len(rangeSplitByDay); i++ {
+		startTime := rangeSplitByDay[i-1]
+		endTime := rangeSplitByDay[i]
+		log.Debugf("Fetching events from %v to %v", startTime, endTime)
+		evts, cursor, err := t.client.SearchUnstructuredEvents(
+			ctx,
+			startTime,
+			endTime,
+			"default",
+			t.config.Types,
+			t.config.BatchSize,
+			types.EventOrderAscending,
+			t.cursor,
+		)
+		if err != nil {
+			return nil, "", trace.Wrap(err)
+		}
+
+		// if no events are found, the cursor is out of the range [startTime, endTime]
+		// and it's the last complete day, update start time to the next day.
+		if len(evts) == 0 && i < len(rangeSplitByDay)-2 {
+			log.Infof("No events found for the range %v to %v", startTime, endTime)
+			// update start time to the next day
+			if err := t.state.SetStartTime(&endTime); err != nil {
+				return nil, "", trace.Wrap(err)
+			}
+			continue
+		}
+		// if any events are found, return them
+		return evts, cursor, nil
+
+	}
+	return nil, t.cursor, nil
+}
+
+func splitRangeByDay(from, to time.Time) []time.Time {
+	// splitRangeByDay splits the range into days
+	var days []time.Time
+	for d := from; d.Before(to); d = d.AddDate(0, 0, 1) {
+		days = append(days, d)
+	}
+	return append(days, to) // add the last date
 }
 
 // pause sleeps for timeout seconds

event-handler/teleport_events_watcher_test.go

@@ -27,6 +27,7 @@ import (
 	"github.com/gravitational/teleport/api/types"
 	"github.com/gravitational/teleport/api/types/events"
 	"github.com/gravitational/trace"
+	"github.com/peterbourgon/diskv/v3"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/net/context"
 )
@@ -121,6 +122,12 @@ func (c *mockTeleportEventWatcher) Close() error {
 }
 
 func newTeleportEventWatcher(t *testing.T, eventsClient TeleportSearchEventsClient) *TeleportEventsWatcher {
+	dv := diskv.New(diskv.Options{
+		BasePath:     t.TempDir(),
+		Transform:    func(s string) []string { return []string{} },
+		CacheSizeMax: cacheSizeMaxBytes,
+	})
+
 	client := &TeleportEventsWatcher{
 		client: eventsClient,
 		pos:    -1,
@@ -130,6 +137,7 @@ func newTeleportEventWatcher(t *testing.T, eventsClient TeleportSearchEventsClie
 				ExitOnLastEvent: true,
 			},
 		},
+		state: &State{dv},
 	}
 
 	return client