Removing outdated files

[Jan Danielsson]

Hello all,

I have a backup system which produces files using the following pattern:

<basename>.<date>.<extension>

For instance:

documents.2007-01-01.tar.bz2.gpg
documents.2007-01-02.tar.bz2.gpg
.
.
.
system_files.2007-01-01.tar.bz2.gpg
system_files.2007-01-02.tar.bz2.gpg
.
.
.
etc.

Obviously, I have little need for *all* those files. What I want to
do is to delete old files according to this pattern:

- Keep all backup files which are two weeks, or less, old
- If backups are more than two weeks old, then keep only the latest
one for each week.
- If backups are more than two months old, then keep only the latest
one for each month.
- If backups are more than two years old, then keep only the latest
one for each year.

I have generated a list of files, parsed the date from the entries,
and created date object from them. I have a list where I have grouped
the "basenames" together. I.e. (lists in a list):

documents
2007-01-01
2007-01-02
.
.
.
system_files
2007-01-01
2007-01-02
.
.
.

Now all I have to do is iterate through the date-lists for each of
the basenames, and apply the rules! Well..

How does one group by week, for instance? I'd like to create a new
set of lists which looks like this:

basename:documents
week:01
2007-01-01
2007-01-02
week:02
2007-01-07
2007-01-08

Date-grouping is dead easy in SQL, but I don't feel like resorting to
postgresql just for this.

I've been looking at the datetime.date class, but I can't see any
easy way to parse the week number from it. I could calculate this
information by brute force -- but I get a feeling that there are
functions in Python to extract week numbers from a date.

--
Kind regards,
Jan Danielsson
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[Gabriel Genellina]

I've been looking at the datetime.date class, but I can't see any
easy way to parse the week number from it. I could calculate this
information by brute force -- but I get a feeling that there are
functions in Python to extract week numbers from a date.

..isocalendar()


--
Gabriel Genellina
Softlab SRL






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[Jan Danielsson]

.isocalendar()

.thanks()

 

[Laurent Pointal]

Jan Danielsson a écrit :

Hello all,

I have a backup system which produces files using the following pattern: ....

Obviously, I have little need for *all* those files. What I want to
do is to delete old files according to this pattern:

- Keep all backup files which are two weeks, or less, old
- If backups are more than two weeks old, then keep only the latest
one for each week.
- If backups are more than two months old, then keep only the latest
one for each month.
- If backups are more than two years old, then keep only the latest
one for each year.

You should take a look at snapy, AFAIR it does things like this to
manage snapshot backups (with cp [+rsync] [+ssh]).

http://www.flibuste.net/libre/snapy/