Friday, March 30, 2012

SCIM Interop Event at IETF 83rd Meeting

First interop event organized by SCIM working group (or originally named as Cloud Directory WG), was held in the room: Corot of hotel Concorde La Fayette, Paris on 28th of March from 6-12 CET. 

Purpose: The purpose of this event was to bring together current working implementations of SCIM and test the level of interoperability between each other which in turn could be used as a valuable input to prove the interoperability of the SCIM spec itself for the Birds of Feathers Session  that was held on 29th of March, in order to form a SCIM working group in IETF.

SCIM (Simple Cloud Identity Management) is an emerging standard that is focused on identity provisioning. You may refer to my previous post to get an overview of SCIM. 

Erik & Samuel from Technology Nexus,
Kelly from Sailpoint,
Chuck from Salesforce,
Trey from UnboundID,
Travis from Ping Identity,
Morteza from Cisco,
Emmanuel from BCPSOFT,
Hasini from WSO2,
participated in person while Michael  from Gluu and James from Curion, participated remotely.

Following are some pics I took during the interop event:

Rest of the post is mainly about the interop experiences of WSO2 Charon when it was tested against SCIM service providers and SCIM Clients provided by other implementations.

WSO2 Charon:
Charon is the open source SCIM implementation offered by WSO2 under Apache 2.0 license. You may refer to my previous blog posts to get an idea about WSO2 Charon. Milestone 1 of WSO2 Charon was released in the time for first interop event. You may refer to a nice blog post written by Prabath on M1 release of Charon. We hosted a public SCIM endpoint for interop testing at

At the start of the interop event, Every one shared their server credentials with participants and started testing by picking one endpoint at a time and sending requests from their clients.

WSO2 Charon SCIM Client was tested against the SCIM endpoints provided by following SCIM service provider implementations:
  • Technology Nexus
  • UnboundID
  • Curion
  • Salesforce
  • Ping Identity 
This list doesn't contain all in the participants list above, since Sailpoint offers only a SCIM Client implementation and other service provider endpoints were busy with fixing some of the issues encountered during the interop event.

Varying level of successes achieved when Charon client tested with each of the above endpoints among which highest percentage of success was achieved with Unbound Identity(8 out of 10 scenarios passed) and Technology Nexus(6 out of 10 scenarios passed) endpoints. 

WSO2 Charon-Samples module includes sample SCIM clients which cover all the SCIM operations supported by Charon as of its M1 release. These sample SCIM client programs made it easy to cover all the other working SCIM server endpoints during the 6 hours time period of the interop event.

Interop issues found:  Following are some of the issues found when testing WSO2 Charon client with other server endpoints which caused some operations to fail. We negotiated and discussed about how to align the implementations with the spec in order to overcome those issues.

1.Server expects ETag when update and delete requests are sent from client side. While it is a good feature to support resource versioning in server side, it should not be mandatory for client to set it according to the spec. Therefore agreed that server side should also allow handle the requests which doesn't contain ETag header.

2. Server returns an error when read-only attributes are contained in the payload of an update request. According to the spec: "Consumers must retrieve the entire Resource and PUT the desired modifications as the operation overwrites all previously stored data." The example payloads in the spec also contains read-only "id" attribute in the update request. Therefore, we agreed that spec needs more clarifications whether it should fail or ignore the read-only attributes in the update request payload and update only other attributes.

3. Server had an internal requirement to include a group attribute when creating a user and if a group is not provided, create user operation fails. But according to the spec, group attribute in User resource is read-only. Therefore, we agreed that servers should not mandate to expect group attribute in create User request payload, even if they have internal server requirements to do so.

4. Server replies with dateTime attributes formatted in .NET DateTime strings. WSO2 Charon client expects date time attributes be formatted in XML Schema Datatypes Specification (2008-01-23T04:56:22Z) which is mentioned in SCIM spec. Agreed to follow the same format for dateTime as specified in SCIM spec in order to avoid interop issues even on these minor areas.

5. Server doesn't add an id attribute rather considers external ID as the id of the resource. Still it is not made mandatory to make it unique which may cause issues in retrieving a particular resource.

Other SCIM Clients were tested against WSO2 Charon SCIM service provider endpoints:
  • Curion
  • Technology Nexus
This list too doesn't contain all in the participants list above, because it took participants quite some time to test against one endpoint and the duration of the interop was 6 hours.

Note: WSO2 Charon endpoint is available for public access and you may carry out interop testing with it anytime and please let us know if you find any issues.

Interop issues found: Following is the only issue reported by the ones who tested against WSO2 Charon endpoint:

1. List user operation returning "resource not found" error.
This operation returns proper response with the list of resources like below, when List user operation is performed with WSO2 Charon client. :
But due to an interop issue when the same was performed with other clients, it shows an unexpected behavior which needs to be reproduced and identified with that particular client.

Overall Comments:
I consider the whole interop event was an effective session where we were able to discuss and agree on interpretation of certain points of the spec wrt implementation aspects and identify areas of the spec which needs more clarification in order to overcome some of the interop issues mentioned above. 

It was also a good community meetup where the people who are communicating remotely over the mailing list could get together and meet in person and make their implementations communicate with each other. 
I would like to Thank all participants for collaborating effectively during the session to make the interop event a success.

Now the SCIM spec has a new beginning at IETF after the successful BOF session which was held 29th of March 2012, and the standard will have a long journey to go till it is published as a RFC in IETF.

WSO2 Charon road map in brief:
WSO2 Charon will be feature completed with its 1.0 release and will be integrated into WSO2 Identity Server 4.0.0 so that WSO2 product stack and WSO2 Stratos will be equipped with the standardized identity provisioning feacture based on SCIM.

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