Add support for policy types, 'erasure_coding' policy

[OpenStack Infra]

https://review.openstack.org/169985
commit ed5406628884432e23bbabb02d2855d4b51a332d
Author: Tushar Gohad <email address hidden>
Date: Mon Jun 30 11:14:28 2014 -0700

    Add support for policy types, 'erasure_coding' policy

    This patch extends the StoragePolicy class for non-replication storage
    policies, the first one being "erasure coding".

    Changes:

     - Add 'policy_type' support to BaseStoragePolicy class
     - Disallow direct instantiation of BaseStoragePolicy class

     - Subclass BaseStoragePolicy

       - "StoragePolicy":
         . Replication policy, default
         . policy_type = 'replication'

       - "ECStoragePolicy":
         . Erasure Coding policy
         . policy_type = 'erasure_coding'
         . Private member variables
           ec_type (EC backend),
           ec_num_data_fragments (number of fragments original
             data split into after erasure coding operation),
           ec_num_parity_fragments (number of parity fragments
           generated during erasure coding)
         . Private methods
           EC specific attributes and ring validator methods.

     - Swift will use PyECLib, a Python Erasure Coding library, for
       erasure coding operations. PyECLib is already an approved
       OpenStack core requirement.
       (https://bitbucket.org/kmgreen2/pyeclib/)

     - Add test cases for
       - 'policy_type' StoragePolicy member
       - policy_type == 'erasure_coding'

    DocImpact

    Co-Authored-By: Alistair Coles <email address hidden>
    Co-Authored-By: Thiago da Silva <email address hidden>
    Co-Authored-By: Clay Gerrard <email address hidden>
    Co-Authored-By: Paul Luse <email address hidden>
    Co-Authored-By: Samuel Merritt <email address hidden>
    Co-Authored-By: Christian Schwede <email address hidden>
    Co-Authored-By: Yuan Zhou <email address hidden>
    Change-Id: Ie0e09796e3ec45d3e656fb7540d0e5a5709b8386
    Implements: blueprint ec-proxy-work

[Atsushi SAKAI (sakaia)]

From seeing swift document, storage_policy is defined in configuration file.
Of course, storage-policy "name" can be selected, but erasure-code itself cannot be selected.
So I think it is relate to manual, no relation to api-site.
Is my understanding is incorrect?

Configuring Policies
https://github.com/openstack/swift/blob/2.3.0/doc/source/overview_policies.rst

[Alexandra Settle (alexandra-settle)]

These are essentially the same bug: https://bugs.launchpad.net/openstack-manuals/+bug/1357139

One or either of these can be closed and since nobody is assigned to this bug, I will close this one and move Atsushi Sakai's comment over.

Thanks.