Authentication and Authorization

Authentication methods

GraceDB supports three different types of authentication methods depending on the entry point:

  • Web interface: gracedb.ligo.org/ supports Shibboleth with federated identities.
  • REST API: The API has a single entry point which can handle the following types of authentication:
    • Shibboleth
    • X509
    • Basic (password-based)

Unauthenticated, read-only access is also available for both the web interface and the API. Only a limited set of information is available to unauthenticated users.

GraceDB permissions

After a user has successfully authenticated, GraceDB examines the user’s group memberships to determine whether the user is authorized to access or modify a particular resource. These permissions apply at the level of individual events. The relevant permissions are: view (which allows viewing) and change (which allows annotation). In most cases, LVC users have both permissions on all events. By contrast, LV-EM members (and, in the future, other external users) have permissions only on events that have been vetted for distribution through the EM followup alert network. This restriction is to avoid possible confusion with injections, glitches, pipeline testing etc. Membership in a special administrators group is required to alter the permissions on an event.

Creating new events in a non-test group (e.g., CBC or Burst) requires a special populate permission on the relevant pipeline object. These permissions are set at the user (rather than group) level and are maintained by hand. Send email to the GraceDB maintainer or the uwm-help queue if you need a new Pipeline or pipeline permission.

Robot certificates

Access to the REST API through the X509 entry point requires a valid robot certificate. (Note: This is only necessary for LVC users. LV-EM users can see Scripted access for LV-EM members .) Instructions for obtaining a certificate are available here. When you send the certificate signing request (CSR) to the rt-auth queue, make sure to indicate that you intend to use the robot certificate to access GraceDB.

Robot keytabs

Robot keytabs are now available by going to robots.ligo.org and clicking on “Apply for a shibboleth automaton keytab.” However, the version of the GraceDB Python client that works with the Kerberos ticket cache has not yet been released. You can get this version of the client by cloning the client source and checking out the shibbolized_client branch. After running kinit with your robot keytab to obtain a valid ticket cache, you can use the Shibbolized client as follows:

from ligo.gracedb.rest import GraceDb, HTTPError

SERVICE = "https://gracedb.ligo.org/api/"
SHIB_SESSION_ENDPOINT = "https://gracedb.ligo.org/Shibboleth.sso/Session"

client = GraceDb(SERVICE, SHIB_SESSION_ENDPOINT)

try:
    r = client.ping()
except HTTPError, e:
    print e.message

print "Response code: %d" % r.status
print "Response content: %s" % r.json()