[Tilecache] make dir error

[Fredrik Lundh]

>  i just tried myself having a look into the source code, but i am a totally rookie in python. surrounding the self.makedirs() statement with a try: / finally: did not do the job and resulted in another error.

you want

    try:
         ...
    except OSError:
         pass

instead of try-finally (the latter catches exceptions and reraises them).

the real reason for this is that os.makedirs isn't quite robust enough
for parallel use; it does catch "already exists" errors (errno 17) for
intermediate directory levels, but not for the final node.  to fix
this, TileCache could do something like:

    import errno, os

    def safe_mkdir(path):
        if os.path.isdir(path):
            return
        try:
            os.makedirs(path)
        except OSError, e:
            if e.errno != errno.EEXIST:
                raise

and then use safe_mkdir instead of any isdir/makedirs combo.

</F>