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Re: creating size-limited tar files

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On 7 November 2012 21:52, Andrea Crotti <andrea.crotti.0@gmail.com> wrote:
> On 11/07/2012 08:32 PM, Roy Smith wrote:
>>
>> In article <509ab0fa$0$6636$9b4e6d93@newsspool2.arcor-online.net>,
>>   Alexander Blinne <news@blinne.net> wrote:
>>
>>> I don't know the best way to find the current size, I only have a
>>> general remark.
>>> This solution is not so good if you have to impose a hard limit on the
>>> resulting file size. You could end up having a tar file of size "limit +
>>> size of biggest file - 1 + overhead" in the worst case if the tar is at
>>> limit - 1 and the next file is the biggest file. Of course that may be
>>> acceptable in many cases or it may be acceptable to do something about
>>> it by adjusting the limit.
>
> But the other problem is that at the moment the people that get our chunks
> reassemble the file with a simple:
>
> cat file1.tar.gz file2.tar.gz > file.tar.gz
>
> which I suppose is not going to work if I create 2 different tar files,
> since it would recreate the header in all of the them, right?

Correct. But if you read the rest of Alexander's post you'll find a
suggestion that would work in this case and that can guarantee to give
files of the desired size.

You just need to define your own class that implements a write()
method and then distributes any data it receives to separate files.
You can then pass this as the fileobj argument to the tarfile.open
function:
http://docs.python.org/2/library/tarfile.html#tarfile.open


Oscar

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creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-07 17:13 +0000
  Re: creating size-limited tar files Neil Cerutti <neilc@norwich.edu> - 2012-11-07 18:40 +0000
  Re: creating size-limited tar files Alexander Blinne <news@blinne.net> - 2012-11-07 20:05 +0100
    Re: creating size-limited tar files Roy Smith <roy@panix.com> - 2012-11-07 15:32 -0500
      Re: creating size-limited tar files Andrea Crotti <andrea.crotti.0@gmail.com> - 2012-11-07 21:52 +0000
      Re: creating size-limited tar files Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2012-11-07 23:15 +0000
      Re: creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-08 10:11 +0000
      Re: creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-08 10:29 +0000
      Re: creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-09 10:39 +0000
      Re: creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-13 10:31 +0000
      Re: creating size-limited tar files Ian Kelly <ian.g.kelly@gmail.com> - 2012-11-13 09:07 -0700
      Re: creating size-limited tar files Ian Kelly <ian.g.kelly@gmail.com> - 2012-11-13 09:25 -0700
      Re: creating size-limited tar files Ian Kelly <ian.g.kelly@gmail.com> - 2012-11-13 09:30 -0700
      Re: creating size-limited tar files Kushal Kumaran <kushal.kumaran+python@gmail.com> - 2012-11-14 11:35 +0530
      Re: creating size-limited tar files Ian Kelly <ian.g.kelly@gmail.com> - 2012-11-14 00:22 -0700
      Re: creating size-limited tar files Kushal Kumaran <kushal.kumaran+python@gmail.com> - 2012-11-14 14:21 +0530
      Re: creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-14 11:52 +0000
      Re: creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-14 15:56 +0000
      Re: creating size-limited tar files Dave Angel <d@davea.name> - 2012-11-14 11:10 -0500
      Re: creating size-limited tar files andrea crotti <andrea.crotti.0@gmail.com> - 2012-11-14 16:16 +0000
  Re: creating size-limited tar files Dave Angel <d@davea.name> - 2012-11-14 11:33 -0500
  Re: creating size-limited tar files Andrea Crotti <andrea.crotti.0@gmail.com> - 2012-11-14 20:43 +0000
  Re: creating size-limited tar files Dave Angel <d@davea.name> - 2012-11-14 15:57 -0500

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