Setting absolute date based Amazon S3 bucket lifecycles with curl

Sun, 06 Jul 2014 11:45:27 +0100
backups, s3

For my local backup regimen I use flexbackup to create a full backup twice a year and differential/incremental backups on a weekly/monthly basis. I then upload these to a new amazon S3 bucket for each half year (so each bucket corresponds to the a full backup plus the associated differentials and incrementals).

I then set the bucket's lifecycle to archive to glacier (cheaper offline storage) from the month after that half year has ended (reducing costs) and to delete it a year after the half ends. It used to be possible to do this via the S3 web interface but the absolute date based options seem to have been removed in favour of time since last update, which is not what I want. However the UI will still display such lifecycles if they are configured and directs you to the REST API to set them up.

I had a look around but couldn't any existing CLI tools to do this directly but I figured it must be possible with curl. A little bit of reading later I found that it was possible but it involved some faff calculating signatures etc. Luckily EricW has written Amazon S3 Authentication Tool for Curl (AKA s3curl) which automates the majority of that faff. The tool is "New BSD" licensed according to that page or Apache 2.0 license according to the included LICENSE file and code comments.

Setup

Following the included README setup ~/.s3curl containing your id and secret key (I called mine personal which I then use below).

Getting the existing lifecycle

Retrieving an existing lifecycle is pretty easy. For the bucket which I used for the first half of 2014:

$ s3curl --id=personal -- --silent http://$bucket.s3.amazonaws.com/?lifecycle | xmllint --format -
<?xml version="1.0" encoding="UTF-8"?>
<LifecycleConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
  <Rule>
    <ID>Archive and Expire</ID>
    <Prefix/>
    <Status>Enabled</Status>
    <Transition>
      <Date>2014-07-31T00:00:00.000Z</Date>
      <StorageClass>GLACIER</StorageClass>
    </Transition>
    <Expiration>
      <Date>2015-01-31T00:00:00.000Z</Date>
    </Expiration>
  </Rule>
</LifecycleConfiguration>

See GET Bucket Lifecycle for details of the XML.

Setting a new lifecycle

The desired configuration needs to be written to a file. For example to set the lifecycle for the bucket I'm going to use for the second half of 2014:

$ cat s3.lifecycle
<LifecycleConfiguration>
  <Rule>
    <ID>Archive and Expire</ID>
    <Prefix/>
    <Status>Enabled</Status>
    <Transition>
      <Date>2015-01-31T00:00:00.000Z</Date>
      <StorageClass>GLACIER</StorageClass>
    </Transition>
    <Expiration>
      <Date>2015-07-31T00:00:00.000Z</Date>
    </Expiration>
  </Rule>
</LifecycleConfiguration>
$ s3curl --id=personal --put s3.lifecycle --calculateContentMd5 -- http://$bucket.s3.amazonaws.com/?lifecycle

See PUT Bucket Lifecycle for details of the XML.