Best (simplest) way to share data between processes

[MRAB]

On 2024-07-07 23:27, Barry via Python-list wrote:
> 
> 
>> On 7 Jul 2024, at 22:13, Chris Green via Python-list <python-list at python.org> wrote:
>> 
>> a simple file lock can then
>> be used to prevent simultaneous access (well, simultaneous access when
>> the writing process is writing).
> 
> There is a simple pattern to make this robust.
> 
> Write new values to a tmp file.
> Close the tmp file.
> Then use os.rename(tmpfile, productionfile).
> 
> This is guaranteed that any process that reads the file will only see all the old file contents or all the new file contents,  never a mix of both.
> 
For clarity I'd recommend os.replace instead. This is because on Windows 
os.rename it would complain if the target file already exists, but 
os.replace has the same behaviour on both Linux and Windows.