Files
deb-python-openstacksdk/doc/source/users/guides/object_store.rst
Brian Curtin 244fb87f4a Adjust object_store to use upload/download names
object_store had been using create_object and save_object names, but
we've previously aggreed to use upload and download for those types of
calls.

Change-Id: I59a17cc29a989096820093ac7e6dba87c1f58b66
Partial-Bug: #1488631
2015-11-06 12:18:03 -06:00

212 lines
8.3 KiB
ReStructuredText

Using OpenStack Object Store
============================
Before working with the Object Store service, you'll need to create a
connection to your OpenStack cloud by following the :doc:`connect` user
guide. This will provide you with the ``conn`` variable used in the examples
below.
.. contents:: Table of Contents
:local:
The primary resources of the Object Store service are containers and objects.
Working with Containers
-----------------------
Listing Containers
******************
To list existing containers, use the
:meth:`~openstack.object_store.v1._proxy.Proxy.containers` method. ::
>>> for cont in conn.object_store.containers():
... print cont
...
openstack.object_store.v1.container.Container: {u'count': 5,
u'bytes': 500, u'name': u'my container'}
openstack.object_store.v1.container.Container: {u'count': 0,
u'bytes': 0, u'name': u'empty container'}
openstack.object_store.v1.container.Container: {u'count': 100,
u'bytes': 1000000, u'name': u'another container'}
The ``containers`` method returns a generator which yields
:class:`~openstack.object_store.v1.container.Container` objects. It handles
pagination for you, which can be adjusted via the ``limit`` argument.
By default, the ``containers`` method will yield as many containers as the
service will return, and it will continue requesting until it receives
no more. ::
>>> for cont in conn.object_store.containers(limit=500):
... print(cont)
...
<500 Containers>
... another request transparently made to the Object Store service
<500 more Containers>
...
Creating Containers
*******************
To create a container, use the
:meth:`~openstack.object_store.v1._proxy.Proxy.create_container` method. ::
>>> cont = conn.object_store.create_container(name="new container")
>>> cont
openstack.object_store.v1.container.Container: {'name': u'new container'}
Working with Container Metadata
*******************************
To get the metadata for a container, use the
:meth:`~openstack.object_store.v1._proxy.Proxy.get_container_metadata` method.
This method either takes the name of a container, or a
:class:`~openstack.object_store.v1.container.Container` object, and it returns
a `Container` object with all of its metadata attributes set. ::
>>> cont = conn.object_store.get_container_metadata("new container")
openstack.object_store.v1.container.Container: {'content-length': '0',
'x-container-object-count': '0', 'name': u'new container',
'accept-ranges': 'bytes',
'x-trans-id': 'tx22c5de63466e4c05bb104-0054740c39',
'date': 'Tue, 25 Nov 2014 04:57:29 GMT',
'x-timestamp': '1416889793.23520', 'x-container-read': '.r:mysite.com',
'x-container-bytes-used': '0', 'content-type': 'text/plain; charset=utf-8'}
To set the metadata for a container, use the
:meth:`~openstack.object_store.v1._proxy.Proxy.set_container_metadata` method.
This method takes a :class:`~openstack.object_store.v1.container.Container`
object. For example, to grant another user write access to this container,
you can set the
:attr:`~openstack.object_store.v1.container.Container.write_ACL` on a
resource and pass it to `set_container_metadata`. ::
>>> cont.write_ACL = "big_project:another_user"
>>> conn.object_store.set_container_metadata(cont)
openstack.object_store.v1.container.Container: {'content-length': '0',
'x-container-object-count': '0',
'name': u'my new container', 'accept-ranges': 'bytes',
'x-trans-id': 'txc3ee751f971d41de9e9f4-0054740ec1',
'date': 'Tue, 25 Nov 2014 05:08:17 GMT',
'x-timestamp': '1416889793.23520', 'x-container-read': '.r:mysite.com',
'x-container-bytes-used': '0', 'content-type': 'text/plain; charset=utf-8',
'x-container-write': 'big_project:another_user'}
Working with Objects
--------------------
Objects are held in containers. From an API standpoint, you work with
them using similarly named methods, typically with an additional argument
to specify their container.
Listing Objects
***************
To list the objects that exist in a container, use the
:meth:`~openstack.object_store.v1._proxy.Proxy.objects` method.
If you have a :class:`~openstack.object_store.v1.container.Container`
object, you can pass it to ``objects``. ::
>>> print cont.name
pictures
>>> for obj in conn.object_store.objects(cont):
... print obj
...
openstack.object_store.v1.container.Object:
{u'hash': u'0522d4ccdf9956badcb15c4087a0c4cb',
u'name': u'pictures/selfie.jpg', u'bytes': 15744,
'last-modified': u'2014-10-31T06:33:36.618640',
u'last_modified': u'2014-10-31T06:33:36.618640',
u'content_type': u'image/jpeg', 'container': u'pictures',
'content-type': u'image/jpeg'}
...
Similar to the :meth:`~openstack.object_store.v1._proxy.Proxy.containers`
method, ``objects`` returns a generator which yields
:class:`~openstack.object_store.v1.obj.Object` objects stored in the
container. It also handles pagination for you, which you can adjust
with the ``limit`` parameter, otherwise making each request for the maximum
that your Object Store will return.
If you have the name of a container instead of an object, you can also
pass that to the ``objects`` method. ::
>>> for obj in conn.object_store.objects("pictures".decode("utf8"),
limit=100):
... print obj
...
<100 Objects>
... another request transparently made to the Object Store service
<100 more Objects>
Getting Object Data
*******************
Once you have an :class:`~openstack.object_store.v1.obj.Object`, you get
the data stored inside of it with the
:meth:`~openstack.object_store.v1._proxy.Proxy.get_object_data` method. ::
>>> print ob.name
message.txt
>>> data = conn.object_store.get_object_data(ob)
>>> print data
Hello, world!
Additionally, if you want to save the object to disk, the
:meth:`~openstack.object_store.v1._proxy.Proxy.download_object` convenience
method takes an :class:`~openstack.object_store.v1.obj.Object` and a
``path`` to write the contents to. ::
>>> conn.object_store.download_object(ob, "the_message.txt")
Uploading Objects
*****************
Once you have data you'd like to store in the Object Store service, you use
the :meth:`~openstack.object_store.v1._proxy.Proxy.upload_object` method.
This method takes the ``data`` to be stored, along with at least an object
``name`` and the ``container`` it is to be stored in. ::
>>> hello = conn.object_store.upload_object(container="messages",
name="helloworld.txt",
data="Hello, world!")
>>> print hello
openstack.object_store.v1.container.Object: {'content-length': '0',
'container': u'messages', 'name': u'helloworld.txt',
'last-modified': 'Tue, 25 Nov 2014 17:39:29 GMT',
'etag': '5eb63bbbe01eeed093cb22bb8f5acdc3',
'x-trans-id': 'tx3035d41b03334aeaaf3dd-005474bed0',
'date': 'Tue, 25 Nov 2014 17:39:28 GMT',
'content-type': 'text/html; charset=UTF-8'}
Working with Object Metadata
****************************
Working with metadata on objects is identical to how it's done with
containers. You use the
:meth:`~openstack.object_store.v1._proxy.Proxy.get_object_metadata` and
:meth:`~openstack.object_store.v1._proxy.Proxy.set_object_metadata` methods.
The metadata attributes to be set can be found on the
:class:`~openstack.object_store.v1.obj.Object` object. ::
>>> secret.delete_after = 300
>>> secret = conn.object_store.set_object_metadata(secret)
We set the :attr:`~openstack.object_store.obj.Object.delete_after`
value to 500 seconds, causing the object to be deleted in 300 seconds,
or five minutes. That attribute corresponds to the ``X-Delete-After``
header value, which you can see is returned when we retreive the updated
metadata. ::
>>> conn.object_store.get_object_metadata(ob)
openstack.object_store.v1.container.Object: {'content-length': '11',
'container': u'Secret Container',
'name': u'selfdestruct.txt', 'x-delete-after': 300,
'accept-ranges': 'bytes', 'last-modified': 'Tue, 25 Nov 2014 17:50:45 GMT',
'etag': '5eb63bbbe01eeed093cb22bb8f5acdc3',
'x-timestamp': '1416937844.36805',
'x-trans-id': 'tx5c3fd94adf7c4e1b8f334-005474c17b',
'date': 'Tue, 25 Nov 2014 17:50:51 GMT', 'content-type': 'text/plain'}