GOCDB/Release4/Development/ExtensibilityMechanism

<< Back to GOCDB/Documentation_Index
<< Back to GOCDB/Release4/Development

Key-Value Pair Property Bag Extensiblity Mechanism

Introduction

• Original RT request: https://rt.egi.eu/rt/Ticket/Display.html?id=3764
• Simiar to the GLUE2 extensibility mechanim, the core GOCDB entities (NGIs, Sites, Services, ServiceGroups, Endpoints) will be extended so that they can define an optional set of custom key-value pairs.
• In doing this, additional parameters could be supplied to the PI for selecting entities that define a particular set of properties. For example "select all Sites/Services that define the 'MPI=true' property."
• As an extensibility mechanism, we do not intend to impose any restrictions on the values of key-value pairs (other than max length, e.g. 256 chars). Key-value pair meaninings should be determined as a community folksonomy.

PI Examples

The URL query could be parameterised with a known GET request paramter (e.g. 'properties') with a LDAP syntax query string for the value, eg:

• https://goc.egi.eu/gocdbpi/private/?method=get_service_endpoint&properties=(MPI=True)

This query would return all <SERVICE_ENDPOINT> elements that support the 'MPI' property with a value of 'True'.

• https://goc.egi.eu/gocdbpi/private/?method=get_service_endpoint&properties=(MPI=*)

This query would return all <SERVICE_ENDPOINT> elements that support the 'MPI' property with any value.

• https://goc.egi.eu/gocdbpi/private/?method=get_service_endpoint&properties=(&(MPI=*)(somekey=true))

This query would return all <SERVICE_ENDPOINT> elements that both support the 'MPI' property with any value and the 'somekey' property with a value of 'valueX'.

Note:

• The extent to which the ldap syntax query string would be supported will have to be explored. A simplified version including only exact pattern matches and simple wildcards may cover most use cases.
• The property bags may only be applied to a subset of entities and PI queries.

Sample PI XML Output

<?xml version="1.0" encoding="UTF-8"?>
<results>
   <SERVICE_ENDPOINT PRIMARY_KEY="50257G0">
      <PRIMARY_KEY>123456G0</PRIMARY_KEY>
      <HOSTNAME>some.host.ac.uk</HOSTNAME>
      <GOCDB_PORTAL_URL>https://goc.egi.eu/portal/index.php?Page_Type=View_Object&amp;object_id=123456&amp;grid_id=0</GOCDB_PORTAL_URL>
      <HOST_OS>SL5</HOST_OS>
      <BETA>N</BETA>
      <SERVICE_TYPE>SomeComputeService</SERVICE_TYPE>
      <CORE></CORE>
      <IN_PRODUCTION>Y</IN_PRODUCTION>
      <NODE_MONITORED>Y</NODE_MONITORED>
      <SITENAME>DGIREF</SITENAME>
      <COUNTRY_NAME>Germany</COUNTRY_NAME>
      <COUNTRY_CODE>DE</COUNTRY_CODE>
      <ROC_NAME>NGI_DE</ROC_NAME>
      <ENDPOINT>
         <URL>ldap://ce-cms.vinca.rs:2170/mds-vo-name=AEGIS10-VINCA-CMS,o=grid</URL>
         <InterfaceName>RIS</InterfaceName>
      </ENDPOINT>   
      <!-- Key-Value Pair Property Bag attached to SERVICE_ENDPOINT entity -->
      <Extensions>
            <Extension>
                <LocalID>1234</LocalID>
                <Key>MPI</Key>
                <Value>True</Value> 
            </Extension>
            <Extension>
                <LocalID>12345</LocalID>
                <Key>somekey</Key>
                <Value>valueX</Value> 
            </Extension>
      </Extensions>
   </SERVICE_ENDPOINT>

</results>

Potential Use Cases

A number of potential use cases have been reported (https://rt.egi.eu/rt/Ticket/Display.html?id=3764), including:

• Specifying service access protocol.
• Defining custom monitoring parameters.
• Defining custom functionality/capability flags supported by a service (this may be related to MPI in EGI requirements, see: https://documents.egi.eu/public/RetrieveFile?docid=1260&version=3&filename=VT-MPI_Report_v3_final.pdf and https://rt.egi.eu/rt/Ticket/Display.html?id=3396).