7e98020b83
The beginning of the compute user guide. This also begins the simplification of the examples, makes them more specific, and adds testing. Change-Id: Ic4bac2fe30601c196b03ce73b2dd04a916231f33 Partial-Bug: #1487269 Partial-Bug: #1419012 Partial-Bug: #1466180
212 lines
8.3 KiB
ReStructuredText
212 lines
8.3 KiB
ReStructuredText
Using OpenStack Object Store
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============================
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Before working with the Object Store service, you'll need to create a
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connection to your OpenStack cloud by following the :doc:`connect` user
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guide. This will provide you with the ``conn`` variable used in the examples
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below.
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.. contents:: Table of Contents
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:local:
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The primary resources of the Object Store service are containers and objects.
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Working with Containers
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-----------------------
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Listing Containers
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******************
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To list existing containers, use the
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:meth:`~openstack.object_store.v1._proxy.Proxy.containers` method. ::
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>>> for cont in conn.object_store.containers():
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... print cont
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...
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openstack.object_store.v1.container.Container: {u'count': 5,
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u'bytes': 500, u'name': u'my container'}
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openstack.object_store.v1.container.Container: {u'count': 0,
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u'bytes': 0, u'name': u'empty container'}
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openstack.object_store.v1.container.Container: {u'count': 100,
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u'bytes': 1000000, u'name': u'another container'}
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The ``containers`` method returns a generator which yields
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:class:`~openstack.object_store.v1.container.Container` objects. It handles
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pagination for you, which can be adjusted via the ``limit`` argument.
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By default, the ``containers`` method will yield as many containers as the
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service will return, and it will continue requesting until it receives
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no more. ::
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>>> for cont in conn.object_store.containers(limit=500):
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... print(cont)
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...
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<500 Containers>
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... another request transparently made to the Object Store service
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<500 more Containers>
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...
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Creating Containers
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*******************
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To create a container, use the
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:meth:`~openstack.object_store.v1._proxy.Proxy.create_container` method. ::
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>>> cont = conn.object_store.create_container(name="new container")
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>>> cont
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openstack.object_store.v1.container.Container: {'name': u'new container'}
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Working with Container Metadata
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*******************************
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To get the metadata for a container, use the
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:meth:`~openstack.object_store.v1._proxy.Proxy.get_container_metadata` method.
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This method either takes the name of a container, or a
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:class:`~openstack.object_store.v1.container.Container` object, and it returns
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a `Container` object with all of its metadata attributes set. ::
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>>> cont = conn.object_store.get_container_metadata("new container")
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openstack.object_store.v1.container.Container: {'content-length': '0',
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'x-container-object-count': '0', 'name': u'new container',
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'accept-ranges': 'bytes',
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'x-trans-id': 'tx22c5de63466e4c05bb104-0054740c39',
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'date': 'Tue, 25 Nov 2014 04:57:29 GMT',
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'x-timestamp': '1416889793.23520', 'x-container-read': '.r:mysite.com',
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'x-container-bytes-used': '0', 'content-type': 'text/plain; charset=utf-8'}
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To set the metadata for a container, use the
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:meth:`~openstack.object_store.v1._proxy.Proxy.set_container_metadata` method.
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This method takes a :class:`~openstack.object_store.v1.container.Container`
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object. For example, to grant another user write access to this container,
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you can set the
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:attr:`~openstack.object_store.v1.container.Container.write_ACL` on a
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resource and pass it to `set_container_metadata`. ::
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>>> cont.write_ACL = "big_project:another_user"
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>>> conn.object_store.set_container_metadata(cont)
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openstack.object_store.v1.container.Container: {'content-length': '0',
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'x-container-object-count': '0',
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'name': u'my new container', 'accept-ranges': 'bytes',
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'x-trans-id': 'txc3ee751f971d41de9e9f4-0054740ec1',
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'date': 'Tue, 25 Nov 2014 05:08:17 GMT',
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'x-timestamp': '1416889793.23520', 'x-container-read': '.r:mysite.com',
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'x-container-bytes-used': '0', 'content-type': 'text/plain; charset=utf-8',
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'x-container-write': 'big_project:another_user'}
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Working with Objects
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--------------------
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Objects are held in containers. From an API standpoint, you work with
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them using similarly named methods, typically with an additional argument
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to specify their container.
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Listing Objects
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***************
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To list the objects that exist in a container, use the
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:meth:`~openstack.object_store.v1._proxy.Proxy.objects` method.
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If you have a :class:`~openstack.object_store.v1.container.Container`
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object, you can pass it to ``objects``. ::
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>>> print cont.name
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pictures
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>>> for obj in conn.object_store.objects(cont):
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... print obj
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...
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openstack.object_store.v1.container.Object:
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{u'hash': u'0522d4ccdf9956badcb15c4087a0c4cb',
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u'name': u'pictures/selfie.jpg', u'bytes': 15744,
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'last-modified': u'2014-10-31T06:33:36.618640',
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u'last_modified': u'2014-10-31T06:33:36.618640',
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u'content_type': u'image/jpeg', 'container': u'pictures',
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'content-type': u'image/jpeg'}
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...
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Similar to the :meth:`~openstack.object_store.v1._proxy.Proxy.containers`
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method, ``objects`` returns a generator which yields
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:class:`~openstack.object_store.v1.obj.Object` objects stored in the
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container. It also handles pagination for you, which you can adjust
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with the ``limit`` parameter, otherwise making each request for the maximum
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that your Object Store will return.
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If you have the name of a container instead of an object, you can also
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pass that to the ``objects`` method. ::
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>>> for obj in conn.object_store.objects("pictures".decode("utf8"),
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limit=100):
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... print obj
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...
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<100 Objects>
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... another request transparently made to the Object Store service
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<100 more Objects>
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Getting Object Data
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*******************
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Once you have an :class:`~openstack.object_store.v1.obj.Object`, you get
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the data stored inside of it with the
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:meth:`~openstack.object_store.v1._proxy.Proxy.get_object_data` method. ::
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>>> print ob.name
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message.txt
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>>> data = conn.object_store.get_object_data(ob)
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>>> print data
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Hello, world!
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Additionally, if you want to save the object to disk, the
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:meth:`~openstack.object_store.v1._proxy.Proxy.save_object` convenience
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method takes an :class:`~openstack.object_store.v1.obj.Object` and a
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``path`` to write the contents to. ::
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>>> conn.object_store.save_object(ob, "the_message.txt")
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Creating Objects
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****************
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Once you have data you'd like to store in the Object Store service, you use
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the :meth:`~openstack.object_store.v1._proxy.Proxy.create_object` method.
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This method takes the ``data`` to be stored, along with at least an object
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``name`` and the ``container`` it is to be stored in. ::
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>>> hello = conn.object_store.create_object(container="messages",
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name="helloworld.txt",
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data="Hello, world!")
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>>> print hello
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openstack.object_store.v1.container.Object: {'content-length': '0',
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'container': u'messages', 'name': u'helloworld.txt',
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'last-modified': 'Tue, 25 Nov 2014 17:39:29 GMT',
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'etag': '5eb63bbbe01eeed093cb22bb8f5acdc3',
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'x-trans-id': 'tx3035d41b03334aeaaf3dd-005474bed0',
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'date': 'Tue, 25 Nov 2014 17:39:28 GMT',
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'content-type': 'text/html; charset=UTF-8'}
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Working with Object Metadata
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****************************
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Working with metadata on objects is identical to how it's done with
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containers. You use the
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:meth:`~openstack.object_store.v1._proxy.Proxy.get_object_metadata` and
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:meth:`~openstack.object_store.v1._proxy.Proxy.set_object_metadata` methods.
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The metadata attributes to be set can be found on the
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:class:`~openstack.object_store.v1.obj.Object` object. ::
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>>> secret.delete_after = 300
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>>> secret = conn.object_store.set_object_metadata(secret)
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We set the :attr:`~openstack.object_store.obj.Object.delete_after`
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value to 500 seconds, causing the object to be deleted in 300 seconds,
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or five minutes. That attribute corresponds to the ``X-Delete-After``
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header value, which you can see is returned when we retreive the updated
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metadata. ::
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>>> conn.object_store.get_object_metadata(ob)
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openstack.object_store.v1.container.Object: {'content-length': '11',
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'container': u'Secret Container',
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'name': u'selfdestruct.txt', 'x-delete-after': 300,
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'accept-ranges': 'bytes', 'last-modified': 'Tue, 25 Nov 2014 17:50:45 GMT',
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'etag': '5eb63bbbe01eeed093cb22bb8f5acdc3',
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'x-timestamp': '1416937844.36805',
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'x-trans-id': 'tx5c3fd94adf7c4e1b8f334-005474c17b',
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'date': 'Tue, 25 Nov 2014 17:50:51 GMT', 'content-type': 'text/plain'}
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