You can store multiple versions of your content so that you can recover from unintended overwrites. Object versioning is an easy way to implement version control, which you can use with any type of content.
Note | |
---|---|
You cannot version a large-object manifest file, but the large-object manifest file can point to versioned segments. |
It is strongly recommended that you put non-current objects in a different container than the container where current object versions reside.
To enable and use object versioning
To enable object versioning, ask your cloud provider to set the
allow_versions
option toTRUE
in the container configuration file.Create an
archive
container to store older versions of objects.Create the
archive
container:# curl -i $publicURL/archive -X PUT -H "Content-Length: 0" -H "X-Auth-Token: $token"
HTTP/1.1 201 Created Content-Length: 0 Content-Type: text/html; charset=UTF-8 X-Trans-Id: tx46f8c29050834d88b8d7e-0052e1859d Date: Thu, 23 Jan 2014 21:11:57 GMT
Create a
current
container to store current versions of objects.Include the
X-Versions-Location
header. This header defines the container that holds the non-current versions of your objects. You must UTF-8-encode and then URL-encode the container name before you include it in theX-Versions-Location
header. This header enables object versioning for all objects in thecurrent
container. Changes to objects in thecurrent
container automatically create non-current versions in thearchive
container.Create the
current
container:# curl -i $publicURL/current -X PUT -H "Content-Length: 0" -H "X-Auth-Token: $token" -H "X-Versions-Location: archive"
HTTP/1.1 201 Created Content-Length: 0 Content-Type: text/html; charset=UTF-8 X-Trans-Id: txb91810fb717347d09eec8-0052e18997 Date: Thu, 23 Jan 2014 21:28:55 GMT
Create the first version of an object in the
current
container:# curl -i $publicURL/current/my_object --data-binary 1 -X PUT -H "Content-Length: 0" -H "X-Auth-Token: $token"
HTTP/1.1 201 Created Last-Modified: Thu, 23 Jan 2014 21:31:22 GMT Content-Length: 0 Etag: d41d8cd98f00b204e9800998ecf8427e Content-Type: text/html; charset=UTF-8 X-Trans-Id: tx5992d536a4bd4fec973aa-0052e18a2a Date: Thu, 23 Jan 2014 21:31:22 GMT
Nothing is written to the non-current version container when you initially PUT an object in the
current
container. However, subsequent PUT requests that edit an object trigger the creation of a version of that object in thearchive
container.These non-current versions are named as follows:
<length><object_name><timestamp>
Where
length
is the 3-character, zero-padded hexadecimal character length of the object,<object_name>
is the object name, and<timestamp>
is the time when the object was initially created as a current version.Create a second version of the object in the
current
container:# curl -i $publicURL/current/my_object --data-binary 2 -X PUT -H "Content-Length: 0" -H "X-Auth-Token: $token"
HTTP/1.1 201 Created Last-Modified: Thu, 23 Jan 2014 21:41:32 GMT Content-Length: 0 Etag: d41d8cd98f00b204e9800998ecf8427e Content-Type: text/html; charset=UTF-8 X-Trans-Id: tx468287ce4fc94eada96ec-0052e18c8c Date: Thu, 23 Jan 2014 21:41:32 GMT
Issue a GET request to a versioned object to get the current version of the object. You do not have to do any request redirects or metadata lookups.
List older versions of the object in the
archive
container:# curl -i $publicURL/archive?prefix=009my_object -X GET -H "X-Auth-Token: $token"
HTTP/1.1 200 OK Content-Length: 30 X-Container-Object-Count: 1 Accept-Ranges: bytes X-Timestamp: 1390513280.79684 X-Container-Bytes-Used: 0 Content-Type: text/plain; charset=utf-8 X-Trans-Id: tx9a441884997542d3a5868-0052e18d8e Date: Thu, 23 Jan 2014 21:45:50 GMT 009my_object/1390512682.92052
Note A POST request to a versioned object updates only the metadata for the object and does not create a new version of the object. New versions are created only when the content of the object changes.
Issue a DELETE request to a versioned object to remove the current version of the object and replace it with the next-most current version in the non-current container.
# curl -i $publicURL/current/my_object -X DELETE -H "X-Auth-Token: $token"
HTTP/1.1 204 No Content Content-Length: 0 Content-Type: text/html; charset=UTF-8 X-Trans-Id: tx006d944e02494e229b8ee-0052e18edd Date: Thu, 23 Jan 2014 21:51:25 GMT
List objects in the
archive
container to show that the archived object was moved back to thecurrent
container:# curl -i $publicURL/archive?prefix=009my_object -X GET -H "X-Auth-Token: $token"
HTTP/1.1 204 No Content Content-Length: 0 X-Container-Object-Count: 0 Accept-Ranges: bytes X-Timestamp: 1390513280.79684 X-Container-Bytes-Used: 0 Content-Type: text/html; charset=UTF-8 X-Trans-Id: tx044f2a05f56f4997af737-0052e18eed Date: Thu, 23 Jan 2014 21:51:41 GMT
This next-most current version carries with it any metadata last set on it. If want to completely remove an object and you have five versions of it, you must DELETE it five times.
To disable object versioning for the
current
container, remove itsX-Versions-Location
metadata header by sending an empty key value.# curl -i $publicURL/current -X PUT -H "Content-Length: 0" -H "X-Auth-Token: $token" -H "X-Versions-Location: "
HTTP/1.1 202 Accepted Content-Length: 76 Content-Type: text/html; charset=UTF-8 X-Trans-Id: txe2476de217134549996d0-0052e19038 Date: Thu, 23 Jan 2014 21:57:12 GMT <html><h1>Accepted</h1><p>The request is accepted for processing.</p></html>