Issue #3 consider filestamp of file before downloading

sync_sftp.py

@@ -1,6 +1,8 @@
 import os
-import logging
 import sys
+import pathlib
+import datetime
+import logging
 
 import tqdm
 import paramiko.util
@@ -23,14 +25,29 @@ def download_files():
             for file_name in tqdm.tqdm(settings.files, file=sys.stdout):
                 source = os.path.join(settings.paths['source'], file_name)
                 destination = os.path.join(settings.paths['destination'], file_name)
-                sftp.get(source, destination)
+                remote_timestamp, destination_timestamp = sftp.stat(source).st_mtime, pathlib.Path(
+                    destination).stat().st_mtime
+                if remote_timestamp > destination_timestamp:
+                    sftp.get(source, destination)
+                else:
+                    logging.info(f"Remote file {file_name} - {ts(remote_timestamp)} has lower or equal timestamp "
+                                 f"as destination file {destination} - {ts(destination_timestamp)}. Download skipped.")
     except socket.timeout as msg:
         logging.warning(f"A timeout was ignored: Actual exception message: {msg}")
         pass
 
     return None
 
 
-if __name__ == '__main__':
+def ts(timestamp: float) -> str:
+    """Return human readable time from `timestamp`.
+
+    :param timestamp: st_mtime from file.
+    """
+    dt = datetime.datetime.fromtimestamp(timestamp)
 
+    return dt.strftime("%Y-%m-%d %H:%M:%S")
+
+
+if __name__ == '__main__':
     download_files()