Temporary directory persist across program runs

Question

I need a temporary directory, but I want full control over its creation and deletion.

I will use this directory to place git repositories which I want to monitor for new commits, so I need to store them somewhere permanently.

Therefore I want to avoid /tmp dir, since it can be cleared by user(?). What is the best practice for this?

Answer 1

http://pypi.python.org/pypi/appdirs is a Python module that offers a cross-platform user_cache_dir function.

Answer 2

tempfile.mkdtemp will create a temp dir for you and return its name. It will create it in /tmp by default (on Unix-like systems), but "in the most secure manner possible" and with read/write/list permissions only for the caller's user id.

>>> d = tempfile.mktemp()
>>> with open(os.path.join(d, "secret")) as output:
...     output.write("Ha, you can't read this!")

(Btw., on a Unix/Linux system with default settings, users can't just edit or remove each others' files from /tmp.)

Answer 3

I'd say that the best practice is to use tempfile.mkdtemp.

If you don't wan to use /tmp then, you can take advantage of the prefix parameter:

import tempfile
tempfile.mkdtemp(prefix=<your_preferred_directory>)

Edit: Regarding what's the most appropriate directory to sotre your application configuration, cache data, etc. If you're using linux, please have a look at the XDG Base Directory Specification.

Answer 4

If it's really temporary, follow larmans' advice and use mkdtemp.

If it's some sort of semi-permanent cache that must survive reboots, then you should use the local application directory, as defined by your OS (%APPDATA%, ~/.local/ etc); some toolkits (e.g. Qt) provide functions to look that folder up in a cross-platform manner.

Edit: from Wikipedia:

• HOME (Unix-like) and USERPROFILE (Microsoft Windows) - indicate where a user's home directory is located in the file system.
• HOME/{.AppName} (Unix-like) and APPDATA{DeveloperName\AppName} (Microsoft Windows) - for storing application settings. Many open source programs incorrectly use USERPROFILE for application settings in Windows - USERPROFILE should only be used in dialogs that allow user to choose between paths like Documents/Pictures/Downloads/Music, for programmatic purposes use APPDATA (roaming), LOCALAPPDATA or PROGRAMDATA (shared between users)

So you should look up os.environ['APPDATA'] or os.environ['HOME'], depending on platform (see sys.platform) and then append your app name, and then you can store there anything you want.

mydir = os.path.join( ".myAppName", "cache")
homeVar = 'HOME'  # default for all *nix variants
if sys.platform == 'win32': 
   homeVar = 'APPDATA'
mydir = os.path.join( os.environ[homeVar], mydir)

Answer 5

Usually programs use a ~/.progname directory to store data that should be persistent but should stay "out of the way" of the user.

Answer 6

Just a though: You may want to look into git commit hooks. That way, instead of monitoring a tmp directory for new commits (sounds strange: who would commit into a tmp directory with limited permissions?) the repo informs you about commits, or, more specifically, automatically runs a script whenever a commit occurs..