MetadataSearch

Proposed Metadata Search API

This document is a work in progress used to define the proposed API for searching account, container, and object metadata in Swift/Object Storage. It was discussed in a design summit session on 7 November 2013 at the Ice House summit in Hong Kong.

Blueprint: https://blueprints.launchpad.net/swift/+spec/searchable-metadata
Etherpad: https://etherpad.openstack.org/p/icehouse-swift-metadata-search
Session: http://icehousedesignsummit.sched.org/event/66176e0859c0fc933d50988b5dc89c12

• Existing implementations
  • SoftLayer: http://sldn.softlayer.com/article/API-Operations-Search-Services

Search API Version

• Extends base Swift API
• Doesn't affect existing base request handling
• Search API Version independent of base API version, e.g.:

    GET /<object storage API version>[/<account>[/<container>[/<object>]]]?<search API version>/...

Search scopes

• An object (unlikely to be used): /acct1/cont2/obj3
• A container (and all of its objects): /acct1/cont2
• An account (and all of its containers and objects): /acct1
• The entire object store (across all accounts): [/]

Search criteria

   [&query=[(]<query expr1>[ [AND|OR] <query expr2>][)][ [AND|OR]...] ]

...where:

   query expr=<query attr><operator><query value>

...and `<operator>` is one of:

   =, !=, <, <=, >, >=, ~

• Note: Generating SQL query for complex boolean expressions across multiple tables may be complex! (If using SQL)
• Simpler: support only AND (multiple ANDs OK)
• Services request shows whether simple (ANDs only) or complex supported