[Python-Dev] best place for an atomic file API (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Thu Feb 16 11:08:26 CET 2012

Am 16.02.2012 10:54, schrieb Victor Stinner:

Most users don't need a truly ACID write, but implement their own best-effort function. Instead of having a different implement in each project, Python can provide something better, especially when the OS provides low level function to implement such feature.

It's then critical how this is named, IMO (and exactly what semantics it comprises). Calling it "atomic" when it is not is a mistake.

Also notice that one user commented that that he already implemented something like this, and left out the issue of permissions. I found that interesting, since preserving permissions might indeed a requirement in a lot of "in-place update" use cases, but hasn't been considered in this discussion yet.

So rather than providing a mechanism for atomic writes, I think providing a mechanism to update a file is what people might need.

One way of providing this might be a "u" mode for open, which updates an existing file on close (unlike "a", which appends, and unlike "w", which truncates first).

Regards, Martin

More information about the Python-Dev mailing list