waiting for file lock?

[Christos Georgiou]

On Tue, 11 Apr 2006 19:07:19 +1200, rumours say that Lawrence D'Oliveiro
<ldo at geek-central.gen.new_zealand> might have written:

>In article <1144725394.174399.4030 at j33g2000cwa.googlegroups.com>,
> s99999999s2003 at yahoo.com wrote:
>
>>i need to go into a directory to grab some files and do some
>>processing.
>>The thing is, i need to wait till the process that generates the files
>>in that directory to finish
>>before i can grab the files. eg if file A is being generated and has
>>not finished, my python script will not go into the directory.
>>how can i check that file A has actually finished?

>I wrote a similar system that watches for new files arriving in an 
>"uploads" directory, whether copied there via FTP or using a GUI desktop 
>script. My heuristic was to only process files whose last-modified 
>date/time was at least 5 minutes in the past. My assumption was that it 
>was unlikely that 5 minutes would go by between more information being 
>added to a file.

This works (unless there are long network timeouts, when downloading...),
but another idea is to wait for the existence of a zero-byte sentinel file
that is created last, after the transfer (or process, in general) has ended.

This method is the one that has worked best for me.
-- 
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please stop spamming us."
The Corinthians