Wednesday, 24 September 2008

Service Contracts

A while back I wrote a blog about the WSDL, mainly about the fact that it is not quite what we need to describe the service contract. Last night we had a get-together of Oracle ACEs and Oracle ACE Directors, where we discussed a lot of topics. One of the topics was about the Service Contract.

The discussion focussed on whether or not you need to have things like binding, security and policies in a Service Contract. Soon we found out that you need to forget the WSDL when you're entering such a discussion, because it muddles the discussion.

At 1.30 this morning we quit the discussion, without having reached a consensus. However, it did clear my mind as to my opinion on this matter.

What we do need in a Service Contract is:
- Definition of the interface
- Definition of the Service (what functionality will be delivered, ie what does it do?!)
- Service quality (QoS, SLA, etc)
- Applicable policies
- Allowable bindings

However, this is about the external contract. This does NOT mean that it is all IN the service. For example: adherence to company policies is obviously a matter of importance. However, security and policies are things you should not worry about in a service, but should add to the service before deploying it. It should be decoupled, so that changes in company (security) policies do not lead to changes in the implementation of a service.

As the discussion is not finished, expect me to get back on this real soon. I urge all my readers to comment on this! Would be nice if we could come up with a definition.


  1. Hi Mike,
    Any update on this contract definition debate?
    Before SOAP became equated with webservices and WSDL became an oversimplification ebXML seemed to more systematically attempt to define contracts and usage agreements. I havent looked at it in a long time, any good ideas from there?
    Ruan Malan

  2. Your blog is my stepping stone, my friend. Thanks for the heads up on this subject.
    Service Contracts

  3. This is very nice and informative blog thanks for sharing this informationareService Contractsfully insured to provide your belongings the extra cushion that they might need during the transit and giving you the peace of mind that your valuable possessions are in good hands.