GOCDB/PI/Technical Documentation

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Contents

GOCDB Programmatic Interface

Important information about using the GOCDBPI

Releases, changes and announcements

All client tool using GOCDB should subscribe to the GOCDB discussion mailing list: gocdb-discuss_at_mailman.egi.eu. Releases, new features, changes in methods and general announcements related to this interface are made on this list.

If your application is using the GOCDB Programmatic interface please subscribe to gocdb-discuss or send your subscription request by mail to gocdb-admins_at_mailman.egi.eu.

Interface description

Interface type

GOCDB Programmatic Interface is a REST (Representational State Transfer) based interface over https. The use of https guarantees URLs are properly secured when transiting. Some of the methods are nonetheless public and don't require client side authentication (see #Data protection and access).

Entry point

Enter GOCDB here https://goc.egi.eu/ or directly at https://goc.egi.eu/portal/ to browse and edit the global EGI information. Entry point for every single method is given on method definition pages listed below.

Outputs

Output format is XML. Calling any implemented method will return you a valid DOM document that can be parsed by any tool on client side.

Data protection and access

Protection levels

There are currently 3 protection levels for all methods of the interface

Methods at level 1 are available without restrictions. Level 2 requires client to present a valid recognized X509 certificate (reference CA list is the officially agreed EGI/LCG EUGridPMA list). Level 3 requires client to present a known, registered certificate (certificate DN needs to be stored on GOCDB side for authentication)

How to gain access?

If you need to access protected methods, a valid certificate will be enough. If you need to access private methods, please send a mail to gocdb-admins_at_mailman.egi.eu, indicating:

Data Visiblity

Sites and service endpoints can be shown or hidden from EGI and this affects what data is shown through the PI. By default the PI methods will return only objects that are marked as visible to EGI. For example get_site will, by default, return only sites that are visible to EGI. Similarly, get_downtime will only show downtimes that are linked to EGI service endpoints.

The "scope=Local" parameter can be used to access non-EGI data through the PI. For example: https://goc.egi.eu/gocdbpi/private/?method=get_site&scope=Local

Our user facing documentation for this feature is available at GOCDB/Input_System_User_Documentation#Data_Visibility_.2F_Scopes.

Available methods

Method name type description Protection level
get_site read - generic Returns site information, grouped by site 2
get_site_list read - generic Returns a list of sites with minimal associated information 1
get_site_contacts read - generic Returns a list of persons (and associated info) having a role at site level, grouped per site 2
get_site_security_info read - generic Returns security contact information for sites 2
get_roc_list read - generic Returns a list of NGIs with minimal associated information 1
get_subgrid_list read - generic Returns a list of Subgrids (i.e. registered sub-parts of an NGI) with minimal associated information 1
get_roc_contacts read - generic Returns NGI contact details, including NGI contact mail address and list of NGI staff 2
get_egee_contacts read - generic Returns a list of contacts for staff that have a role a EGI level 2
get_downtime read - generic Returns a list of service downtimes (downtimes are repeated for each affected service) 1
get_downtime_nested_services read - generic Returns a list of downtimes with affected services nested as child elements of the downtime 1
get_service_endpoint read - generic Returns a list of services (single node x single service) and associated information (same as get_service) 1
get_service read - generic Returns a list of services (single node x single service) and associated information (same as get_service_endpoint) 1
get_service_types read - generic Returns a list of valid service types and associated description 1
get_user read - generic Returns a user or a list of users with associated details and roles 2
get_downtime_to_broadcast read - dedicated Returns the list of downtimes recently declared with notification settings for CIC portal downtime notification service 1
get_cert_status_changes read - generic Returns a list of changes to certification statuses 2
get_cert_status_date read - generic Returns a list of current certification statuses for Production sites and the date they entered that status 2
get_service_group read - generic Returns a list of service groups and the service endpoints under those groups. 2
get_service_group_role read - generic Returns a list of service groups and the roles held by users over these groups. 2
get_ngi read - generic Returns a list of NGIs with contact information 2
get_project_contacts read - generic Returns a list of persons (and associated info) having a role over a project. 2
get_site_count_per_country read - generic Returns a count of sites per country (not per NGI) 1

Note about parameters:

Client code examples

Simple data retrieval using wget/curl

If getting the data locally is what you're after, a simple cron job retrieving data via wget might do the trick.

$ wget --no-check-certificate -O result.xml 'https://goc.egi.eu/gocdbpi/public/?method=get_site_list&sitename=RAL-LCG2'

--no-check-certificate option (like the -k given for curl below) bypasses server certificate validation; this is handy if you don't have access to a directory containing the appropriate CA certificates, but is not generally recommended; providing the CA directory as in the example below provides the information it needs for such validation. Note also that the URL must be encapsulated in single quotes to protect the ampersand from the shell.

$ wget --certificate=cert.pem --private-key=cert.key.pem --private-key-type=PEM --ca-directory=/etc/grid-security/certificates/ -O result.xml 'https://goc.egi.eu/gocdbpi/private/?method=get_site&sitename=RAL-LCG2'

Note that if you don't specify the --ca-directory option and you haven't asked for --no-check-certificate then the SSL handshake will fail as the server cert check can't be performed.

Note: examples above are shown using wget-10.2. Some discrepencies are observed between version so check wget help for correct options. Bugs and weird behaviour have also been observed for wget with a version older than 10 and using wget on cygwin.

$ curl -k --cert ./cert.pem --key ./key.pem 'https://goc.egi.eu/gocdbpi/public/?method=get_site&sitename=RAL-LCG2'

Note: curl on SL6 uses NSS rather than openssl and this can cause some issues. One problem is that NSS would think "cert.pem" was an alias so you have to turn it into a relative path hence these examples use "./" in front of each filename. Another problem is that in the example above a passphrase isn't always requested for key.pem so one has to be passed in using the --pass option. One method of doing this without leaving your passphrase in your command line history file is as follows:

$ curl -k --cert ./cert.pem --key ./key.pem --pass $(echo -n "enter passphrase: ">&2 ; read -s a ; echo $a) 'https://goc.egi.eu/gocdbpi/public/?method=get_site&sitename=RAL-LCG2'

Perl example

Provided by Emir Imamagic, SRCE. This code is used by NCG

The 3 following examples are GOCDB modules in perl which use LWP::UserAgent for accessing PI and XML::DOM for parsing the data. Data is used to fill internal NCG structure.

Nagios plugin nagios-gocdb-downtime is used for retrieving downtimes and pushing them to Nagios via GridMon::Nagios module:

note Full code is available from cern svn

PHP example

Provided by Guillaume Cessieux, CC-IN2P3. This code is used by ENOC

The following example shows a simple PHP class with methods used to retrieve and parse XML data from GOCDB-PI using PHP curl and simplexml


Python example

Provided by Giuseppe Misurelli, CNAF-INFN

The following example is a Python client that queries the GOCDB programmatic interface, retrieves info about downtimes for a top entity region using curl, parses xml output with the xml.dom.minidom module and stores data into a MySQl db.


Java example

Provided by David Meredith, STFC

import java.io.File;
import java.net.URL;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import org.junit.Test;
 
public class DownloadFileSample {
    // trust all certificates (don't do this is production) 
    TrustManager[] trustAllCerts = new TrustManager[]{
        new X509TrustManager() {
            public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                return null;
            }
            public void checkClientTrusted(
                    java.security.cert.X509Certificate[] certs, String authType) {
            }
            public void checkServerTrusted(
                    java.security.cert.X509Certificate[] certs, String authType) {
            }
        }
    };
 
    @Test 
    public void testIt() throws Exception{
        SSLContext sc = SSLContext.getInstance("SSL");
        sc.init(null, trustAllCerts, new java.security.SecureRandom());
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
        URL url = new URL("https://goc.egi.eu/gocdbpi/public/?method=get_site_list"); 
        File df = File.createTempFile("sampleSiteList", ".xml");
        org.apache.commons.io.FileUtils.copyURLToFile(url, df);
        System.out.println("downloadFile: "+df.getAbsolutePath());
        String version = System.getProperty("java.version");
        System.out.println("Using Java version: "+version);
    }
}

New requests and improvements

Requests on GOCDB-PI can take the form of:

Such requests are logged in The GOCDB RT Requirements Queue Tickets: View and submit RT Requirements tickets specifically for GOCDB

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