A General Information System API in LCG A

A General Information System API in LCG A. Delgado Peris, P. Méndez Lorenzo, S. Campana, F. Donno, R. Santinelli, A. Sciaba’ CERN - Switzerland Introduction The problem Access to the Information System is a fundamental operation for Grid middleware and for VO applications Its Protocol YESTERDAY: LDAP Its Schema Its Query Language New Technology Grid Middleware Its Protocol Vo Users TODAY: R-GMA Its Schema Its Query Language Workload and Data Management Monitoring Tools Their applications New Technology Its Protocol TOMORROW: MDS 3 Its Schema Its Query Language Application SQL Canonical Schema Proposed Solution We propose a general API able to interact with any actual and/or future protocol. General Interface Canonical Schema SQL Semantic Translator Characteristics: 1. Single interface for User Applications. 2. Defined query language and data model are included. 3. The user needs to specify the service he wants to access and the query to perform on the data using the canonical schema. The query and schema are syntactically and semantically translated internally in a transparent manner. Implem. Schema SQL to LDAP Syntactic Tr. Implem. Schema LDAP MDS Info Service Canonical Schema SQL Semantic Translator SQL Implem. Schema SQL to SQL Syntactic Tr. SQL Implem. Schema SQL Interface LDAP Interface Implem. Schema SQL LDAP SQL Implem. Schema R-GMA Info Service Figure 1: General schema of the high level Information System API. This work has been partially funded by the Istituto Nazionale di Fisica Nucleare, Rome – ITALY and by the Ministerio de Educación y Ciencia, Madrid - SPAIN Total Sites: 78 Total CPUs: 7269 Total Storage: 6558 (TB) September 10 2004

The Design Lcg. Info. Interface initialize() connect() disconnet() SQLto. SQLTranslator SQLto. LDAPTranslator SQLto. SQLQuerier Lib. Factory SQLto. LDAPQuerier Info. From. LDAP Info. From. RGMA query() Delivered R-GMA classes for connection, query, etc. Delivered LDAP classes for connection, query, iteration, etc Figure 2: Relational Schema of the classes included in the package User Requirements a) SQL query b) Configuration file which allows users to define the service to query and therefore the specific protocol to be used. The user can also define parameters specific to each protocol. Preliminary Results 1. We have tested successfully typical WMS and Monitoring packages queries SELECT Name Unique. ID Status Running. Jobs FROM Glue. Computing. Element. State 2. Implementation in Mon. ALISA long Lxb 0706. cern. ch: 2119/jobmanager-pbs-short 0 short lxb 0706. cern. cg: 2119/jobmanager-pbs-short 0 [. . . ] 3. Successfully implemented in some tools deployed by LCG Lcg-infosytes: infosytes information tool for LCG Total Sites: 78 Total CPUs: 7269 Total Storage: 6558 (TB) September 10 2004 Figure 3. Interface implementation in Mon. ALISA (ALICE)