Re: [foxboro] File Transfer
- From: stan <stanb@xxxxxxxxx>
- To: "Johnson, Alex P (IPS)" <alex.johnson@xxxxxxxxxxxxxxxx>
- Date: Tue, 7 Oct 2008 17:21:48 -0400
On Tue, Oct 07, 2008 at 04:56:12PM -0400, Johnson, Alex P (IPS) wrote:
> My two cents.
>
> The application that creates the file should move it and signal that the
> move is complete. On many projects, I've used ftp to move the file and
> rsh to run the application that processes the file. This combination
> ensures that the file is fully transferred before processing begins.
>
> Failing that, I will monitor the 'modification date' on the transferred
> file and wait some period after that date before processing the file.
>
>
I agree with Alex on his points. But in practice I have run into a scenario
where we did not have control of the application on the Windows side. So,
what I did was have the DCS side transfer the file, and the Windows side
delete the file after it had processed it. At least I could check (using
ftp) for the existence of the file, and not transfer a new on if the Windows
app has died. I admit it's not an elegant solution, since I have no control
over the Windows side trying to "consume" an incomplete file, since ftp is
not atomic. My original design had their side checking for a lock file, that
I would have transfered _after_ the data file, and them then deleting this
lock file when they were done consuming the data, but it did not get
implemented that way, unfortunately.
--
One of the main causes of the fall of the roman empire was that, lacking
zero, they had no way to indicate successful termination of their C
programs.
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