feat(external-endpoint): Implement heartbeat (#1173)

Fixes #741

storage/store/memory/memory.go

@@ -211,6 +211,23 @@ func (s *Store) DeleteAllTriggeredAlertsNotInChecksumsByEndpoint(ep *endpoint.En
 	return 0
 }
 
+// HasEndpointStatusNewerThan checks whether an endpoint has a status newer than the provided timestamp
+func (s *Store) HasEndpointStatusNewerThan(key string, timestamp time.Time) (bool, error) {
+	s.RLock()
+	defer s.RUnlock()
+	endpointStatus := s.cache.GetValue(key)
+	if endpointStatus == nil {
+		// If no endpoint exists, there's no newer status, so return false instead of an error
+		return false, nil
+	}
+	for _, result := range endpointStatus.(*endpoint.Status).Results {
+		if result.Timestamp.After(timestamp) {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
 // Clear deletes everything from the store
 func (s *Store) Clear() {
 	s.cache.Clear()

storage/store/memory/memory_test.go

@@ -84,6 +84,7 @@ var (
 // This test is simply an extra sanity check
 func TestStore_SanityCheck(t *testing.T) {
 	store, _ := NewStore(storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
+	defer store.Clear()
 	defer store.Close()
 	store.Insert(&testEndpoint, &testSuccessfulResult)
 	endpointStatuses, _ := store.GetAllEndpointStatuses(paging.NewEndpointStatusParams())
@@ -134,3 +135,30 @@ func TestStore_Save(t *testing.T) {
 	store.Clear()
 	store.Close()
 }
+
+func TestStore_HasEndpointStatusNewerThan(t *testing.T) {
+	store, _ := NewStore(storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
+	defer store.Clear()
+	defer store.Close()
+	// Insert a result
+	err := store.Insert(&testEndpoint, &testSuccessfulResult)
+	if err != nil {
+		t.Fatalf("expected no error while inserting result, got %v", err)
+	}
+	// Check with a timestamp in the past
+	hasNewerStatus, err := store.HasEndpointStatusNewerThan(testEndpoint.Key(), time.Now().Add(-time.Hour))
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if !hasNewerStatus {
+		t.Fatal("expected to have a newer status, but didn't")
+	}
+	// Check with a timestamp in the future
+	hasNewerStatus, err = store.HasEndpointStatusNewerThan(testEndpoint.Key(), time.Now().Add(time.Hour))
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if hasNewerStatus {
+		t.Fatal("expected not to have a newer status, but did")
+	}
+}

storage/store/sql/sql.go

@@ -514,6 +514,24 @@ func (s *Store) DeleteAllTriggeredAlertsNotInChecksumsByEndpoint(ep *endpoint.En
 	return int(rowsAffects)
 }
 
+// HasEndpointStatusNewerThan checks whether an endpoint has a status newer than the provided timestamp
+func (s *Store) HasEndpointStatusNewerThan(key string, timestamp time.Time) (bool, error) {
+	if timestamp.IsZero() {
+		return false, errors.New("timestamp is zero")
+	}
+	var count int
+	err := s.db.QueryRow(
+		"SELECT COUNT(*) FROM endpoint_results WHERE endpoint_id = (SELECT endpoint_id FROM endpoints WHERE endpoint_key = $1 LIMIT 1) AND timestamp > $2",
+		key,
+		timestamp.UTC(),
+	).Scan(&count)
+	if err != nil {
+		// If the endpoint doesn't exist, we return false instead of an error
+		return false, nil
+	}
+	return count > 0, nil
+}
+
 // Clear deletes everything from the store
 func (s *Store) Clear() {
 	_, _ = s.db.Exec("DELETE FROM endpoints")

storage/store/sql/sql_test.go

@@ -853,3 +853,36 @@ func TestStore_DeleteAllTriggeredAlertsNotInChecksumsByEndpoint(t *testing.T) {
 		t.Error("expected alert3 to exist for ep2")
 	}
 }
+
+func TestStore_HasEndpointStatusNewerThan(t *testing.T) {
+	store, _ := NewStore("sqlite", t.TempDir()+"/TestStore_HasEndpointStatusNewerThan.db", false, storage.DefaultMaximumNumberOfResults, storage.DefaultMaximumNumberOfEvents)
+	defer store.Close()
+	// Insert an endpoint status
+	if err := store.Insert(&testEndpoint, &testSuccessfulResult); err != nil {
+		t.Fatal("expected no error, got", err.Error())
+	}
+	// Check if it has a status newer than 1 hour ago
+	hasNewerStatus, err := store.HasEndpointStatusNewerThan(testEndpoint.Key(), time.Now().Add(-time.Hour))
+	if err != nil {
+		t.Fatal("expected no error, got", err.Error())
+	}
+	if !hasNewerStatus {
+		t.Error("expected to have a newer status")
+	}
+	// Check if it has a status newer than 2 days ago
+	hasNewerStatus, err = store.HasEndpointStatusNewerThan(testEndpoint.Key(), time.Now().Add(-48*time.Hour))
+	if err != nil {
+		t.Fatal("expected no error, got", err.Error())
+	}
+	if !hasNewerStatus {
+		t.Error("expected to have a newer status")
+	}
+	// Check if there's a status newer than 1 hour in the future (silly test, but it should work)
+	hasNewerStatus, err = store.HasEndpointStatusNewerThan(testEndpoint.Key(), time.Now().Add(time.Hour))
+	if err != nil {
+		t.Fatal("expected no error, got", err.Error())
+	}
+	if hasNewerStatus {
+		t.Error("expected not to have a newer status in the future")
+	}
+}

storage/store/store.go

@@ -57,6 +57,9 @@ type Store interface {
 	// This prevents triggered alerts that have been removed or modified from lingering in the database.
 	DeleteAllTriggeredAlertsNotInChecksumsByEndpoint(ep *endpoint.Endpoint, checksums []string) int
 
+	// HasEndpointStatusNewerThan checks whether an endpoint has a status newer than the provided timestamp
+	HasEndpointStatusNewerThan(key string, timestamp time.Time) (bool, error)
+
 	// Clear deletes everything from the store
 	Clear()