API

ReferenceAPI

Synopsis

The reference API provide the reference data of Grid5000. Information such as the list of sites, clusters, nodes, environments, etc. can be queried using this API. You can also obtain a specific version of any data, list all the versions of a given information, and get an archive of all or part of the data.

REST API

• API entry-point: http://localhost:8080
• note on formats: it is not required to explicitly indicate the format in the URL, e.g.:

 GET /resource.json

You may prefer to set the Accept HTTP header to the correct mime type, e.g.:

 GET /resource
 Accept: application/json

If you put both, the Accept HTTP header will be ignored.

Get a specific version of a resource

 GET /%resource%.%format%?version=%version%

• Accepted formats: json, zip
• Version parameter: can be omitted (latest version is returned), or it can be: a commit id (40 characters length) or a Unix UTC time (number of seconds since the Unix epoch: 1970-01-01 00:00:00 UTC)
• Comments: the zip format will return a zip archive containing the set of directories and files corresponding to the required data.
• Examples:

 GET /.json 

will return the description of Grid5000:

 HTTP/1.1 200 OK
 Etag: "d69bfd1891582824f5a192fa41a3f444a3d52854"
 Last-Modified: Wed, 28 Jan 2009 13:46:19 GMT
 Content-Type: application/json;charset=utf-8
 Content-Length: 345
 Connection: close
 
 {
   "environments": [
     "\/environments\/sid-x64-base-1.0"
   ],
   "sites": [
     "\/sites\/bordeaux",
     "\/sites\/grenoble",
     "\/sites\/lille",
     "\/sites\/lyon",
     "\/sites\/nancy",
     "\/sites\/orsay",
     "\/sites\/rennes",
     "\/sites\/sophia",
     "\/sites\/toulouse"
   ],
   "uid": "grid5000",
   "type": "grid",
   "uri": "\/"
 }
 

You can then follow the URIs to get more information on the sub-resources. For example, you can get more details about Bordeaux by doing:

 GET /sites/bordeaux.json

this will return something like:

 HTTP/1.1 200 OK
 Etag: "45f78b07665ed58f843a741d6927d60a4db35ba3"
 Last-Modified: Wed, 28 Jan 2009 13:46:19 GMT
 Content-Type: application/json;charset=utf-8
 Content-Length: 604
 Connection: close
 
 {
   "environments": [
     "\/sites\/bordeaux\/environments\/sid-x64-base-1.0"
   ],
   "name": "Bordeaux",
   "location": "Bordeaux, France",
   "latitude": null,
   "security_contact": null,
   "clusters": [
     "\/sites\/bordeaux\/clusters\/bordemer",
     "\/sites\/bordeaux\/clusters\/bordeplage",
     "\/sites\/bordeaux\/clusters\/bordereau",
     "\/sites\/bordeaux\/clusters\/borderline"
   ],
   "uid": "bordeaux",
   "type": "site",
   "user_support_contact": null,
   "description": "",
   "longitude": null,
   "email_contact": null,
   "web": null,
   "uri": "\/sites\/bordeaux",
   "sys_admin_contact": null
 }

and so on.

Get the list of all versions of a resource

 GET /%resource%/versions.%format%

• Accepted formats: json
• Response: the list of all changes that were made to the resource.

The API closely follows the principles of the REST architecture. A 404 status code is returned when a resource does not exist. A 500 status code is returned when the server encountered an error. A 200 status code is returned when the request is successful.

Getting Started

Creating an SSH tunnel

The API is only available from the Grid5000 frontends. As a consequence, the first thing you have to do when trying to query an API is to create an SSH tunnel to the API server, via your site's access machine:

 ssh -N -L 8080:131.254.202.98:8080 login@access.site.grid5000.fr

Note: when you are done with your queries, you can hit CTRL-C to destroy the tunnel.

cURL example

 curl -i http://localhost:8080/sites.json

Ruby example

First, make sure you've got *Ruby* and *Rubygems* installed. Then install the required gems:

 sudo gem install rest-client json --no-ri --no-rdoc

Put this code in a g5k-reference-api-client.rb file. It will output the current list of sites and, for each one, the list of its clusters:

 require 'pp'
 require 'rubygems'
 require 'rest_client' # sudo gem install rest-client
 require 'json'        # sudo gem install json

 api = RestClient::Resource.new('http://localhost:8080')
 begin
   puts "---- Getting Grid5000"
   # start at the root of the reference data (= grid5000)
   grid5000 = JSON.parse api['/'].get(:accept => 'application/json')
   pp grid5000
   puts "\n---- Getting sites"
   grid5000['sites'].each do |site_uri|
     site = JSON.parse api[site_uri].get(:accept => 'application/json')
     pp site
     puts "\n---- Getting #{site['uid']} clusters"
     site['clusters'].each do |cluster_uri|
       cluster = JSON.parse api[cluster_uri].get(:accept => 'application/json')
       pp cluster
     end
   end
 rescue RestClient::ResourceNotFound
   puts 'Resource not found.'
 rescue RestClient::RequestTimeout
   puts 'Timeout.'
 rescue RestClient::Unauthorized
   puts 'Unauthorized.'
 rescue RestClient::RequestFailed
   puts 'Request failed.'
 rescue RestClient::ServerBrokeConnection 
   puts 'Connection broken.' 
 rescue Exception => e
   puts e.message
 end

Run with:

 ruby g5k-reference-api-client.rb