filestream: fix 'requires pointer' error

CHANGELOG.next.asciidoc

@@ -59,6 +59,7 @@ https://github.com/elastic/beats/compare/v8.2.0\...main[Check the HEAD diff]
 - Fix Google workspace pagination and document ID generation. {pull}33666[33666]
 - Fix PANW handling of messages with event.original already set. {issue}33829[33829] {pull}33830[33830]
 - Rename identity as identity_name when the value is a string in Azure Platform Logs. {pull}33654[33654]
+- Fix 'requires pointer' error while getting cursor metadata. {pull}33956[33956]
 - Fix input cancellation handling when HTTP client does not support contexts. {issue}33962[33962] {pull}33968[33968]
 - Update mito CEL extension library to v0.0.0-20221207004749-2f0f2875e464 {pull}33974[33974]
 

filebeat/input/filestream/prospector.go

@@ -267,11 +267,12 @@ func (p *fileProspector) onRename(log *logp.Logger, ctx input.Context, fe loginp
 	} else {
 		// update file metadata as the path has changed
 		var meta fileMeta
-		err := s.FindCursorMeta(src, meta)
+		err := s.FindCursorMeta(src, &meta)
 		if err != nil {
-			log.Errorf("Error while getting cursor meta data of entry %s: %v", src.Name(), err)
-
 			meta.IdentifierName = p.identifier.Name()
+			log.Warnf("Error while getting cursor meta data of entry '%s': '%w'"+
+				", using prospector's identifier: '%s'",
+				src.Name(), err, meta.IdentifierName)
 		}
 		err = s.UpdateMetadata(src, fileMeta{Source: fe.NewPath, IdentifierName: meta.IdentifierName})
 		if err != nil {

filebeat/input/filestream/prospector_test.go

@@ -574,11 +574,11 @@ func (mu *mockMetadataUpdater) checkOffset(id string, offset int64) bool {
 }
 
 func (mu *mockMetadataUpdater) FindCursorMeta(s loginp.Source, v interface{}) error {
-	_, ok := mu.table[s.Name()]
+	meta, ok := mu.table[s.Name()]
 	if !ok {
-		return fmt.Errorf("no such id")
+		return fmt.Errorf("no such id [%q]", s.Name())
 	}
-	return nil
+	return typeconv.Convert(v, meta)
 }
 
 func (mu *mockMetadataUpdater) ResetCursor(s loginp.Source, cur interface{}) error {
@@ -654,3 +654,74 @@ func mustPathIdentifier(renamed bool) fileIdentifier {
 	}
 	return pathIdentifier
 }
+
+func TestOnRenameIdentifierMustNotChange(t *testing.T) {
+	events := []loginp.FSEvent{
+		{
+			Op:      loginp.OpRename,
+			OldPath: "/old/path/to/file",
+			NewPath: "/new/path/to/file",
+			Info:    testFileInfo{},
+		},
+	}
+
+	p := fileProspector{
+		filewatcher:       newMockFileWatcher(events, len(events)),
+		identifier:        mustPathIdentifier(true),
+		stateChangeCloser: stateChangeCloserConfig{Renamed: true},
+	}
+	ctx := input.Context{Logger: logp.L(), Cancelation: context.Background()}
+
+	path := "/new/path/to/file"
+	expectedIdentifier := "foo"
+	id := expectedIdentifier + "::" + path
+
+	testStore := newMockMetadataUpdater()
+	testStore.table[id] = fileMeta{Source: path, IdentifierName: expectedIdentifier}
+
+	hg := newTestHarvesterGroup()
+	p.Run(ctx, testStore, hg)
+
+	got := testStore.table[id]
+	meta := fileMeta{}
+	typeconv.Convert(&meta, got)
+
+	if meta.IdentifierName != expectedIdentifier {
+		t.Errorf("fileMeta.IdentifierName must not change, expecting: %q, got: %q", expectedIdentifier, meta.IdentifierName)
+	}
+}
+
+func TestOnRenameFindCursorMetaErrorUseProspectorIdentifier(t *testing.T) {
+	events := []loginp.FSEvent{
+		{
+			Op:      loginp.OpRename,
+			OldPath: "/old/path/to/file",
+			NewPath: "/new/path/to/file",
+			Info:    testFileInfo{},
+		},
+	}
+
+	p := fileProspector{
+		filewatcher:       newMockFileWatcher(events, len(events)),
+		identifier:        mustPathIdentifier(true),
+		stateChangeCloser: stateChangeCloserConfig{Renamed: true},
+	}
+	ctx := input.Context{Logger: logp.L(), Cancelation: context.Background()}
+
+	path := "/new/path/to/file"
+	expectedIdentifier := "path"
+	id := expectedIdentifier + "::" + path
+
+	testStore := newMockMetadataUpdater()
+
+	hg := newTestHarvesterGroup()
+	p.Run(ctx, testStore, hg)
+
+	got := testStore.table[id]
+	meta := fileMeta{}
+	typeconv.Convert(&meta, got)
+
+	if meta.IdentifierName != expectedIdentifier {
+		t.Errorf("fileMeta.IdentifierName must not change, expecting: %q, got: %q", expectedIdentifier, meta.IdentifierName)
+	}
+}