Difference between revisions of "GOCDB/PI/Technical Documentation"
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== GOCDB Programmatic Interface
== GOCDB Programmatic Interface ==
=== Important information about using the GOCDBPI ===
=== Important information about using the GOCDBPI ===
Revision as of 10:31, 25 October 2013
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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.
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).
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.
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.
The associated XML schema for each method is available by calling the method with "&output=xmlschema", e.g. https://goc.egi.eu/gocdbpi/private/?method=get_site&output=xmlschema
Data protection and access
There are currently 3 protection levels for all methods of the interface
- Level 1: public methods (no critical information, no mail, no personal details)
- Level 2: protected methods (contain mails or personal details)
- Level 3: private methods (contains security or critical information)
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:
- Your name and affiliation
- The name and purpose of the tool that need to access the data
- certificate DN of the machine(s) that will retrieve the information
- An e-mail contact for your application, that will be subscribed to the GOCDB-discussion and announcement mailing list if it is not already there.
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.
|Method name||type||description||Protection level|
|get_site||read - generic||Returns site information including contacts, 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||3|
|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 EGI downtimes for sites and nodes||1|
|get_service_endpoint||read - generic||Returns a list of service endpoints (single node x single service) and associated information||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||2|
|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|
Note about parameters:
- Unless otherwise stated, all parameters are optional. If no parameter is given, all methods will return results with the wider scope possible.
- It is possible to combine parameters, for example: ?method=get_site&country=Italy&certification_status=Certified&production_status=Production
Client code examples
Simple data retrieval using wget
If getting the data locally is what you're after, a simple cron job retrieving data via wget might do the trick.
- Public methods: You do not need any client certificate, so a simple wget instruction should work:
$ wget --no-check-certificate -O result.xml 'https://goc.egi.eu/gocdbpi/public/?method=get_site_list&sitename=RAL-LCG2'
--no-check-certificate option might be needed to avoid server verification. Note also that URL should be encapsulated into single quotes.
- Protected and private methods: Here you will need authentication, which can be done through wget as shown in next example:
$ 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, SSL handshake may fail as server cert cannot be checked.
Note: examples 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.
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
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
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.
New requests and improvements
Requests on GOCDB-PI can take the form of:
- Change request to an existing method
- Request for new generic methods
- Request for tool specific methods
Such requests are logged in The GOCDB RT Requirements Queue Tickets: View and submit RT Requirements tickets specifically for GOCDB