© 2006 Open Grid Forum SAGA and SD OGF19 Chapel Hill, NC Steve Fisher

© 2006 Open Grid Forum 2 Inputs Work in gLite (EGEE) on SD Meeting (Copenhagen) between EGEE, OSG, OMII (Europe and UK), Nordugrid, ARC, Globus and FSU decided that SD API is a good thing

© 2006 Open Grid Forum 3 SD architecture in gLite Service Discovery API Applications/Services R-GMA Plug-in BDII Plug-in XML File Plug-in XPath Query R-GMA Info. Systems BDII Info. Systems SQL Query LDAP Query Services publish directly to the information system

© 2006 Open Grid Forum 4 GLUE 1.3 Service Site may have many services Services have n:n self-relationship Service may have service data (key, value) * * * *

© 2006 Open Grid Forum 5 SD API Finding Services Based on various search criteria Includes key/value pairs (open-ended) Can use multiple plugins (and combine the results) Returns a service object Has getter methods Hide implementation Allow changes Optimal efficiency

© 2006 Open Grid Forum 6 listServices Filter strings uses SQL syntax as if it were part of a where clause selecting from a single table. 3 filter strings simplifies the implementation, clarifies the description of the functionality avoids clash with key name being glue attributes. ListServices IN ServiceFilterString IN VOFilterString IN DataFilterString OUT List of service objects"

© 2006 Open Grid Forum 7 Column Names Column names in the service filter are: Type - type of service Name - name of service Site - name of site Endpoint - will normally be used wth the LIKE operator Service - for associated services Column names in the VOFilterString are VO - will often be used with the IN operator Column names in the The DataFilterString are taken from the service data key/value pairs.

© 2006 Open Grid Forum 8 Examples listServices ("Type = 'org.glite.security.voms' ", NULL, NULL) for a matching type ListServices ("Site IN ('INFN-CNAF', 'RAL-LCG2') ", NULL, NULL) all services running at any of the two sites listServices("Type = 'ResourceBroker' AND Site LIKE '%INFN%' ", NULL, NULL) all services matching a type and site name by pattern listServices (NULL, "VO IN ('cms', 'atlas') ", NULL) all services for matching VOs listServices (NULL, "VO = 'dteam'", "source = 'RAL-LCG2' OR destination = 'RAL-LCG2' ") all services of a matching VO and key/value pairs listServices ("Type = 'ResourceBroker' ", NULL, "RunningJobs >=1 AND RunningJobs <= 5 ") all service matching service type and key/value interval listServices ("Endpoint LIKE '%PrimaryProducer%' ", NULL, NULL) all services matching end point pattern

© 2006 Open Grid Forum 9 Going further Have so far done nothing about conformance to SAGA style Currently writing a prototype 3 string selection (to replace current large set of calls) Need to define both the user API the plug-in API Does the approach feel right?

© 2006 Open Grid Forum 10 Full Copyright Notice Copyright (C) Open Grid Forum (2006). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. The limited permissions granted above are perpetual and will not be revoked by the OGF or its successors or assignees.