A management command to put on a cron to keep daily backups of a postgres database (with a 1-week window)

backup_db.py

import datetime
import subprocess

from django.conf import settings
from django.core.management.base import BaseCommand

from boto.s3.connection import S3Connection
from boto.s3.key import Key

class Command(BaseCommand):
    help = "Backs up the database and uploads it to S3"

    def handle(self, *app_labels, **options):
        filename = '%s.dump' % (datetime.date.today(),)
        filepath = '/tmp/%s' % (filename,)
        old_filename = '%s.dump' % (
            datetime.date.today() - datetime.timedelta(days=7),)
        
        cmd = [
            'pg_dump',
            '-h',
            settings.DATABASE_HOST,
            '-p',
            settings.DATABASE_PORT,
            '-c',
            '-Fc',
            '-Z9',
            settings.DATABASE_NAME,
        ]
        
        with open(filepath, 'w') as f:
            with open(filepath + '.err', 'w') as err_f:
                proc = subprocess.Popen(cmd, stdout=f, stderr=err_f)
                proc.wait()
        
        conn = S3Connection(settings.AWS_ACCESS_KEY_ID,
            settings.AWS_SECRET_ACCESS_KEY)
        bucket_name = settings.AWS_STORAGE_BUCKET_NAME + '-db'
        bucket = conn.get_bucket(bucket_name)
        k = Key(bucket)
        k.key = filename
        k.set_contents_from_filename(filepath)
        # Delete the week old backup
        try:
            old = Key(bucket)
            old.key = old_filename
            old.delete()
        except (KeyboardInterrupt, SystemExit):
            raise
        except:
            pass