Attempt to implement streaming of large S3 files to disk for DB impor…

…ting (when restoring)

api/ws/wsHelpers/sync-mongo-restore.go

@@ -79,17 +79,17 @@ func DownloadArchive(svcs *services.APIServices) (string, error) {
 			svcs.Log.Errorf(" Failed to get free disk bytes: %v", err)
 		}
 
-		svcs.Log.Infof(" Downloading: %v... free space: %v bytes", dbFile, freeBytes)
+		svcs.Log.Infof(" Downloading: %v... (%v bytes free)", dbFile, freeBytes)
 
-		dbFileBytes, err := svcs.FS.ReadObject(svcs.Config.DataBackupBucket, dbFile)
+		dbStream, err := svcs.FS.ReadObjectStream(svcs.Config.DataBackupBucket, dbFile)
 		if err != nil {
 			return "", fmt.Errorf("Failed to download remote DB dump file: %v. Error: %v", dbFile, err)
 		}
 
 		// Save locally
 		// Remove remote root dir
 		dbFilePathLocal := strings.TrimPrefix(dbFile, dataBackupS3Path+"/")
-		err = localFS.WriteObject(dataBackupLocalPath, dbFilePathLocal, dbFileBytes)
+		err = localFS.WriteObjectStream(dataBackupLocalPath, dbFilePathLocal, dbStream)
 
 		if err != nil {
 			return "", fmt.Errorf("Failed to write local DB dump file: %v. Error: %v", dbFilePathLocal, err)

core/fileaccess/interface.go

@@ -22,7 +22,10 @@
 // available from
 package fileaccess
 
-import "strings"
+import (
+	"io"
+	"strings"
+)
 
 // Generic interface for reading/writing files asynchronously
 // We could have used OS level things but we want to be able to
@@ -45,6 +48,11 @@ type FileAccess interface {
 	// Writes a file as bytes
 	WriteObject(bucket string, path string, data []byte) error
 
+	// Reads a file as bytes (returning a stream)
+	ReadObjectStream(bucket string, path string) (io.ReadCloser, error)
+	// Writes a file from stream
+	WriteObjectStream(bucket string, path string, stream io.Reader) error
+
 	// Reads a file as JSON and decodes it into itemsPtr
 	ReadJSON(bucket string, s3Path string, itemsPtr interface{}, emptyIfNotFound bool) error
 	// Writes itemsPtr as a JSON file

core/fileaccess/localFileSystem.go

@@ -133,6 +133,36 @@ func (fs *FSAccess) WriteObject(rootPath string, path string, data []byte) error
 	return os.WriteFile(fullPath, data, 0777)
 }
 
+func (fs *FSAccess) ReadObjectStream(rootPath string, path string) (io.ReadCloser, error) {
+	fullPath := fs.filePath(rootPath, path)
+	f, err := os.Open(fullPath)
+	if err != nil {
+		return nil, err
+	}
+
+	return f, nil
+}
+
+func (fs *FSAccess) WriteObjectStream(rootPath string, path string, stream io.Reader) error {
+	fullPath := fs.filePath(rootPath, path)
+
+	// Ensure any subdirs in between are created
+	createPath := filepath.Dir(fullPath)
+	err := os.MkdirAll(createPath, 0777)
+	if err != nil {
+		return err
+	}
+
+	outFile, err := os.Create(fullPath)
+	if err != nil {
+		return err
+	}
+	defer outFile.Close()
+
+	_, err = io.Copy(outFile, stream)
+	return err
+}
+
 func (fs *FSAccess) ReadJSON(rootPath string, s3Path string, itemsPtr interface{}, emptyIfNotFound bool) error {
 	fileData, err := fs.ReadObject(rootPath, s3Path)
 

core/fileaccess/s3.go

@@ -121,6 +121,32 @@ func (s3Access S3Access) WriteObject(bucket string, path string, data []byte) er
 	return err
 }
 
+func (s3Access S3Access) ReadObjectStream(bucket string, path string) (io.ReadCloser, error) {
+	input := &s3.GetObjectInput{
+		Bucket: aws.String(bucket),
+		Key:    aws.String(path),
+	}
+
+	result, err := s3Access.s3Api.GetObject(input)
+	if err != nil {
+		return nil, err
+	}
+
+	return result.Body, nil
+}
+
+func (s3Access S3Access) WriteObjectStream(bucket string, path string, stream io.Reader) error {
+	/*input := &s3.PutObjectInput{
+		Body:   stream,
+		Bucket: aws.String(bucket),
+		Key:    aws.String(path),
+	}
+
+	_, err := s3Access.s3Api.PutObject(input)
+	return err*/
+	return fmt.Errorf("Not implemented")
+}
+
 func (s3Access S3Access) ReadJSON(bucket string, s3Path string, itemsPtr interface{}, emptyIfNotFound bool) error {
 	fileData, err := s3Access.ReadObject(bucket, s3Path)