Peter Portante 5202b0e586 DiskFile API, with reference implementation

Refactor on-disk knowledge out of the object server by pushing the
async update pickle creation to the new DiskFileManager class (name is
not the best, so suggestions welcome), along with the REPLICATOR
method logic. We also move the mount checking and thread pool storage
to the new ondisk.Devices object, which then also becomes the new home
of the audit_location_generator method.

For the object server, a new setup() method is now called at the end
of the controller's construction, and the _diskfile() method has been
renamed to get_diskfile(), to allow implementation specific behavior.

We then hide the need for the REST API layer to know how and where
quarantining needs to be performed. There are now two places it is
checked internally, on open() where we verify the content-length,
name, and x-timestamp metadata, and in the reader on close where the
etag metadata is checked if the entire file was read.

We add a reader class to allow implementations to isolate the WSGI
handling code for that specific environment (it is used no-where else
in the REST APIs). This simplifies the caller's code to just use a
"with" statement once open to avoid multiple points where close needs
to be called.

For a full historical comparison, including the usage patterns see:
https://gist.github.com/portante/5488238

(as of master, 2b639f5, Merge
 "Fix 500 from account-quota     This Commit
 middleware")
--------------------------------+------------------------------------
                                 DiskFileManager(conf)

                                   Methods:
                                     .pickle_async_update()
                                     .get_diskfile()
                                     .get_hashes()

                                   Attributes:
                                     .devices
                                     .logger
                                     .disk_chunk_size
                                     .keep_cache_size
                                     .bytes_per_sync

DiskFile(a,c,o,keep_data_fp=)    DiskFile(a,c,o)

  Methods:                         Methods:
   *.__iter__()
    .close(verify_file=)
    .is_deleted()
    .is_expired()
    .quarantine()
    .get_data_file_size()
                                     .open()
                                     .read_metadata()
    .create()                        .create()
                                     .write_metadata()
    .delete()                        .delete()

  Attributes:                      Attributes:
    .quarantined_dir
    .keep_cache
    .metadata
                                *DiskFileReader()

                                   Methods:
                                     .__iter__()
                                     .close()

                                   Attributes:
                                    +.was_quarantined

DiskWriter()                     DiskFileWriter()

  Methods:                         Methods:
    .write()                         .write()
    .put()                           .put()

* Note that the DiskFile class   * Note that the DiskReader() object
  implements all the methods       returned by the
  necessary for a WSGI app         DiskFileOpened.reader() method
  iterator                         implements all the methods
                                   necessary for a WSGI app iterator

                                 + Note that if the auditor is
                                   refactored to not use the DiskFile
                                   class, see
                                   https://review.openstack.org/44787
                                   then we don't need the
                                   was_quarantined attribute

A reference "in-memory" object server implementation of a backend
DiskFile class in swift/obj/mem_server.py and
swift/obj/mem_diskfile.py.

One can also reference
https://github.com/portante/gluster-swift/commits/diskfile for the
proposed integration with the gluster-swift code based on these
changes.

Change-Id: I44e153fdb405a5743e9c05349008f94136764916
Signed-off-by: Peter Portante <peter.portante@redhat.com>

2013-10-17 15:03:31 -04:00

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Welcome to Swift's documentation!

Swift is a highly available, distributed, eventually consistent object/blob store. Organizations can use Swift to store lots of data efficiently, safely, and cheaply.

This documentation is generated by the Sphinx toolkit and lives in the source tree. Additional documentation on Swift and other components of OpenStack can be found on the OpenStack wiki and at http://docs.openstack.org.

Note

If you're looking for associated projects that enhance or use Swift, please see the associated_projects page.

getting_started

Overview and Concepts

Swift's API docs <http://docs.openstack.org/api/openstack-object-storage/1.0/content/> overview_architecture overview_ring overview_reaper overview_auth overview_replication ratelimit overview_large_objects overview_object_versioning overview_container_sync overview_expiring_objects cors crossdomain associated_projects

Developer Documentation

development_guidelines development_saio development_auth development_ondisk_backends

Administrator Documentation

howto_installmultinode deployment_guide apache_deployment_guide admin_guide replication_network

Source Documentation

ring proxy account container db object misc

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