From 1b641d2c660fa003e73db970cbbbc935345a495d Mon Sep 17 00:00:00 2001 From: Christian Heller Date: Sun, 22 Feb 2015 11:50:03 +0100 Subject: [PATCH] Server/py: Improve atomicity of record(), description of its strategy. --- plomrogue-server.py | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/plomrogue-server.py b/plomrogue-server.py index 47390a4..c9cc20e 100755 --- a/plomrogue-server.py +++ b/plomrogue-server.py @@ -78,8 +78,10 @@ def obey(cmd, io_db, prefix): def record(cmd, io_db): - """Append cmd string plus newline to file at path_recordfile.""" - # Doesn't yet replace old record() fully. + """Append cmd string plus newline to file at path_recordfile. (Atomic.)""" + # This misses some optimizations from the original record(), namely only + # finishing the atomic write with flush() and fsync() every 15 seconds + # unless explicitely forced. Implement as needed. path_tmp = io_db["path_record"] + io_db["tmp_suffix"] if os.access(io_db["path_record"], os.F_OK): shutil.copyfile(io_db["path_record"], path_tmp) @@ -88,6 +90,8 @@ def record(cmd, io_db): file.flush() os.fsync(file.fileno()) file.close() + if os.access(io_db["path_record"], os.F_OK): + os.remove(io_db["path_record"]) os.rename(path_tmp, io_db["path_record"]) -- 2.30.2