Added Manifest file to manage files on disk

internal/file/file_manager_service.go

@@ -7,6 +7,7 @@ package file
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -37,7 +38,16 @@ import (
 //go:generate go run github.com/maxbrunsfeld/counterfeiter/v6@v6.8.1 -generate
 //counterfeiter:generate . fileManagerServiceInterface
 
-const maxAttempts = 5
+const (
+	maxAttempts = 5
+	dirPerm     = 0o755
+	filePerm    = 0o600
+)
+
+var (
+	manifestDirPath  = "/var/lib/nginx-agent"
+	manifestFilePath = manifestDirPath + "/manifest.json"
+)
 
 type (
 	fileOperator interface {
@@ -303,9 +313,12 @@ func (fms *FileManagerService) ConfigApply(ctx context.Context,
 	if fileErr != nil {
 		return model.RollbackRequired, fileErr
 	}
-
 	// Update map of current files on disk
 	fms.UpdateCurrentFilesOnDisk(files.ConvertToMapOfFiles(fileOverview.GetFiles()))
+	manifestFileErr := fms.UpdateManifestFile(files.ConvertToMapOfFiles(fileOverview.GetFiles()))
+	if manifestFileErr != nil {
+		return model.RollbackRequired, manifestFileErr
+	}
 
 	return model.OK, nil
 }
@@ -315,8 +328,10 @@ func (fms *FileManagerService) ClearCache() {
 	clear(fms.fileActions)
 }
 
+// nolint:revive,cyclop
 func (fms *FileManagerService) Rollback(ctx context.Context, instanceID string) error {
 	slog.InfoContext(ctx, "Rolling back config for instance", "instanceid", instanceID)
+	areFilesUpdated := false
 	fms.filesMutex.Lock()
 	defer fms.filesMutex.Unlock()
 	for _, file := range fms.fileActions {
@@ -328,11 +343,11 @@ func (fms *FileManagerService) Rollback(ctx context.Context, instanceID string)
 
 			// currentFilesOnDisk needs to be updated after rollback action is performed
 			delete(fms.currentFilesOnDisk, file.GetFileMeta().GetName())
+			areFilesUpdated = true
 
 			continue
 		case mpi.File_FILE_ACTION_DELETE, mpi.File_FILE_ACTION_UPDATE:
 			content := fms.rollbackFileContents[file.GetFileMeta().GetName()]
-
 			err := fms.fileOperator.Write(ctx, content, file.GetFileMeta())
 			if err != nil {
 				return err
@@ -341,13 +356,21 @@ func (fms *FileManagerService) Rollback(ctx context.Context, instanceID string)
 			// currentFilesOnDisk needs to be updated after rollback action is performed
 			file.GetFileMeta().Hash = files.GenerateHash(content)
 			fms.currentFilesOnDisk[file.GetFileMeta().GetName()] = file
+			areFilesUpdated = true
 		case mpi.File_FILE_ACTION_UNSPECIFIED, mpi.File_FILE_ACTION_UNCHANGED:
 			fallthrough
 		default:
 			slog.DebugContext(ctx, "File Action not implemented")
 		}
 	}
 
+	if areFilesUpdated {
+		manifestFileErr := fms.UpdateManifestFile(fms.currentFilesOnDisk)
+		if manifestFileErr != nil {
+			return manifestFileErr
+		}
+	}
+
 	return nil
 }
 
@@ -436,7 +459,7 @@ func (fms *FileManagerService) checkAllowedDirectory(checkFiles []*mpi.File) err
 
 // DetermineFileActions compares two sets of files to determine the file action for each file. Returns a map of files
 // that have changed and a map of the contents for each updated and deleted file. Key to both maps is file path
-// nolint: revive
+// nolint: revive,cyclop
 func (fms *FileManagerService) DetermineFileActions(currentFiles, modifiedFiles map[string]*mpi.File) (
 	map[string]*mpi.File, map[string][]byte, error,
 ) {
@@ -451,26 +474,31 @@ func (fms *FileManagerService) DetermineFileActions(currentFiles, modifiedFiles
 	fileDiff := make(map[string]*mpi.File)  // Files that have changed, key is file name
 	fileContents := make(map[string][]byte) // contents of the file, key is file name
 
-	// if file is in currentFiles but not in modified files, file has been deleted
+	manifestFiles, manifestFileErr := fms.getManifestFile(currentFiles)
+
+	if manifestFileErr != nil && manifestFiles == nil {
+		return nil, nil, manifestFileErr
+	}
+	// if file is in manifestFiles but not in modified files, file has been deleted
 	// copy contents, set file action
-	for _, currentFile := range currentFiles {
-		fileName := currentFile.GetFileMeta().GetName()
-		_, ok := modifiedFiles[fileName]
+	for fileName, currentFile := range manifestFiles {
+		_, exists := modifiedFiles[fileName]
 
-		if !ok {
+		if !exists {
+			// Read file contents before marking it deleted
 			fileContent, readErr := os.ReadFile(fileName)
 			if readErr != nil {
 				return nil, nil, fmt.Errorf("error reading file %s, error: %w", fileName, readErr)
 			}
 			fileContents[fileName] = fileContent
 			currentFile.Action = &deleteAction
-			fileDiff[currentFile.GetFileMeta().GetName()] = currentFile
+			fileDiff[fileName] = currentFile
 		}
 	}
 
 	for _, file := range modifiedFiles {
 		fileName := file.GetFileMeta().GetName()
-		currentFile, ok := currentFiles[file.GetFileMeta().GetName()]
+		currentFile, ok := manifestFiles[file.GetFileMeta().GetName()]
 		// default to unchanged action
 		file.Action = &unchangedAction
 
@@ -511,3 +539,104 @@ func (fms *FileManagerService) UpdateCurrentFilesOnDisk(currentFiles map[string]
 		fms.currentFilesOnDisk[file.GetFileMeta().GetName()] = file
 	}
 }
+
+func (fms *FileManagerService) UpdateManifestFile(currentFiles map[string]*mpi.File) (err error) {
+	manifestFiles := fms.convertToManifestFileMap(currentFiles)
+	manifestJSON, err := json.MarshalIndent(manifestFiles, "", "  ")
+	if err != nil {
+		slog.Error("Unable to marshal manifest file json ", "err", err)
+		return err
+	}
+
+	// 0755 allows read/execute for all, write for owner
+	if err = os.MkdirAll(manifestDirPath, dirPerm); err != nil {
+		slog.Error("Unable to create directory", "err", err)
+		return err
+	}
+
+	// 0600 ensures only root can read/write
+	newFile, err := os.OpenFile(manifestFilePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, filePerm)
+	if err != nil {
+		slog.Error("Failed to read manifest file", "error", err)
+		return err
+	}
+	defer newFile.Close()
+
+	_, err = newFile.Write(manifestJSON)
+	if err != nil {
+		slog.Error("Failed to write manifest file: %v\n", "error", err)
+		return err
+	}
+
+	return nil
+}
+
+func (fms *FileManagerService) getManifestFile(currentFiles map[string]*mpi.File) (map[string]*mpi.File, error) {
+	if _, err := os.Stat(manifestFilePath); err != nil {
+		return currentFiles, err // Return current files if manifest directory still doesn't exist
+	}
+
+	file, err := os.ReadFile(manifestFilePath)
+	if err != nil {
+		slog.Error("Failed to read manifest file", "error", err)
+		return nil, err
+	}
+
+	var manifestFiles map[string]*model.ManifestFile
+
+	err = json.Unmarshal(file, &manifestFiles)
+	if err != nil {
+		slog.Error("Failed to parse manifest file", "error", err)
+		return nil, err
+	}
+
+	fileMap := fms.convertToFileMap(manifestFiles)
+
+	return fileMap, nil
+}
+
+func (fms *FileManagerService) convertToManifestFileMap(
+	currentFiles map[string]*mpi.File,
+) map[string]*model.ManifestFile {
+	manifestFileMap := make(map[string]*model.ManifestFile)
+
+	for name, file := range currentFiles {
+		if file == nil || file.GetFileMeta() == nil {
+			continue
+		}
+		manifestFile := fms.convertToManifestFile(file)
+		manifestFileMap[name] = manifestFile
+	}
+
+	return manifestFileMap
+}
+
+func (fms *FileManagerService) convertToManifestFile(file *mpi.File) *model.ManifestFile {
+	return &model.ManifestFile{
+		ManifestFileMeta: &model.ManifestFileMeta{
+			Name: file.GetFileMeta().GetName(),
+			Size: file.GetFileMeta().GetSize(),
+			Hash: file.GetFileMeta().GetHash(),
+		},
+	}
+}
+
+func (fms *FileManagerService) convertToFileMap(manifestFiles map[string]*model.ManifestFile) map[string]*mpi.File {
+	currentFileMap := make(map[string]*mpi.File)
+	for name, manifestFile := range manifestFiles {
+		currentFile := fms.convertToFile(manifestFile)
+		currentFileMap[name] = currentFile
+	}
+
+	return currentFileMap
+}
+
+func (fms *FileManagerService) convertToFile(manifestFile *model.ManifestFile) *mpi.File {
+	return &mpi.File{
+		FileMeta: &mpi.FileMeta{
+			Name: manifestFile.ManifestFileMeta.Name,
+			Hash: manifestFile.ManifestFileMeta.Hash,
+			Size: manifestFile.ManifestFileMeta.Size,
+		},
+	}
+}

internal/file/file_manager_service_test.go

@@ -153,6 +153,10 @@ func TestFileManagerService_ConfigApply_Add(t *testing.T) {
 
 	overview := protos.FileOverview(filePath, fileHash)
 
+	manifestDirPath = tempDir
+	manifestFilePath = manifestDirPath + "/manifest.json"
+	helpers.CreateFileWithErrorCheck(t, manifestDirPath, "manifest.json")
+
 	fakeFileServiceClient := &v1fakes.FakeFileServiceClient{}
 	fakeFileServiceClient.GetOverviewReturns(&mpi.GetOverviewResponse{
 		Overview: overview,
@@ -201,6 +205,10 @@ func TestFileManagerService_ConfigApply_Update(t *testing.T) {
 		},
 	}
 
+	manifestDirPath = tempDir
+	manifestFilePath = manifestDirPath + "/manifest.json"
+	helpers.CreateFileWithErrorCheck(t, manifestDirPath, "manifest.json")
+
 	overview := protos.FileOverview(tempFile.Name(), fileHash)
 
 	fakeFileServiceClient := &v1fakes.FakeFileServiceClient{}
@@ -253,6 +261,10 @@ func TestFileManagerService_ConfigApply_Delete(t *testing.T) {
 		},
 	}
 
+	manifestDirPath = tempDir
+	manifestFilePath = manifestDirPath + "/manifest.json"
+	helpers.CreateFileWithErrorCheck(t, manifestDirPath, "manifest.json")
+
 	fakeFileServiceClient := &v1fakes.FakeFileServiceClient{}
 	agentConfig := types.AgentConfig()
 	agentConfig.AllowedDirectories = []string{tempDir}
@@ -368,6 +380,10 @@ func TestFileManagerService_Rollback(t *testing.T) {
 	_, writeErr = updateFile.Write(newFileContent)
 	require.NoError(t, writeErr)
 
+	manifestDirPath = tempDir
+	manifestFilePath = manifestDirPath + "/manifest.json"
+	helpers.CreateFileWithErrorCheck(t, manifestDirPath, "manifest.json")
+
 	filesCache := map[string]*mpi.File{
 		addFile.Name(): {
 			FileMeta: &mpi.FileMeta{
@@ -468,6 +484,10 @@ func TestFileManagerService_DetermineFileActions(t *testing.T) {
 	unmanagedErr := os.WriteFile(unmanagedFile.Name(), unmanagedFileContent, 0o600)
 	require.NoError(t, unmanagedErr)
 
+	manifestDirPath = tempDir
+	manifestFilePath = manifestDirPath + "/manifest.json"
+	helpers.CreateFileWithErrorCheck(t, manifestDirPath, "manifest.json")
+
 	tests := []struct {
 		expectedError   error
 		modifiedFiles   map[string]*mpi.File
@@ -504,7 +524,7 @@ func TestFileManagerService_DetermineFileActions(t *testing.T) {
 			},
 			expectedCache: map[string]*mpi.File{
 				deleteTestFile.Name(): {
-					FileMeta: protos.FileMeta(deleteTestFile.Name(), files.GenerateHash(fileContent)),
+					FileMeta: protos.ManifestFileMeta(deleteTestFile.Name(), files.GenerateHash(fileContent)),
 					Action:   &deleteAction,
 				},
 				updateTestFile.Name(): {
@@ -556,9 +576,10 @@ func TestFileManagerService_DetermineFileActions(t *testing.T) {
 		t.Run(test.name, func(tt *testing.T) {
 			fakeFileServiceClient := &v1fakes.FakeFileServiceClient{}
 			fileManagerService := NewFileManagerService(fakeFileServiceClient, types.AgentConfig())
+			err = fileManagerService.UpdateManifestFile(test.currentFiles)
+			require.NoError(tt, err)
 			diff, contents, fileActionErr := fileManagerService.DetermineFileActions(test.currentFiles,
 				test.modifiedFiles)
-
 			require.NoError(tt, fileActionErr)
 			assert.Equal(tt, test.expectedContent, contents)
 			assert.Equal(tt, test.expectedCache, diff)

internal/model/config.go

@@ -27,6 +27,19 @@ type APIDetails struct {
 	Location string
 }
 
+type ManifestFile struct {
+	ManifestFileMeta *ManifestFileMeta `json:"manifest_file_meta"`
+}
+
+type ManifestFileMeta struct {
+	// The full path of the file
+	Name string `json:"name"`
+	// The hash of the file contents sha256, hex encoded
+	Hash string `json:"hash"`
+	// The size of the file in bytes
+	Size int64 `json:"size"`
+}
+
 // Complexity is 11, allowed is 10
 // nolint: revive, cyclop
 func (ncc *NginxConfigContext) Equal(otherNginxConfigContext *NginxConfigContext) bool {

test/protos/files.go

@@ -21,6 +21,15 @@ func FileMeta(fileName, fileHash string) *mpi.FileMeta {
 	}
 }
 
+func ManifestFileMeta(fileName, fileHash string) *mpi.FileMeta {
+	return &mpi.FileMeta{
+		ModifiedTime: nil,
+		Name:         fileName,
+		Hash:         fileHash,
+		Permissions:  "",
+	}
+}
+
 func CertMeta(fileName, fileHash string) *mpi.FileMeta {
 	lastModified, _ := CreateProtoTime("2024-01-09T13:22:21Z")