Best WCF SOA book that you recommend for the given architecture design

Question

I want to create three WCF services in an intranet. The three WCF services are independent of eachother, in sense of their functionality e.g.

1. Validator Service - Deals with everything that has to do with validating of accounts and account holders. i.e. if an account exists, if card holder exists etc

2. Account Service - Deals with depositing of balance in an account and depositing of balance

3. Limit Service - Deals with checking if the amount user wants to take out is is within an account's limit.

Use case: User wants to deposit some money.

UI starts by calling account service. Account service calls validator service to check if account exists. Validator service returns boolean to indicate if an account exists. If validator service returns true then Account service then deposits money.

User wants to take out money.

UI starts by calling account service. Account service calls validator service if account exists. Validator service returns true. Account service then calls limit service to check if user can take this balance out. If the limit service returns true then accounts service calls appropriate method which reduces balance and gives balance to user.

I am planning to host them as windows services because the UI and all of these services will be deployed on the same machine.

1. What are your thoughts regarding that?

2. Is there any book you recommend that you recommend on such SOA architecture where services communicate with eachother? I am really concerned about its scalability, security and performance.

Thanks.

Answer 1

Why three separate services for operations that are linked like in that way? It seems you are taking SOA to an extreme that you don't need to.

I would create one service that dealt with account actions (deposits, withdrawals, balance inquiries, transfers, etc). Things like validating and limits, unless available to the user, I would put behind the scenes, either as private methods in the contract, or more likely in an underlying DLL that the service would reference.

Having a service that does only one thing is not, in and of itself, bad - but having multiple services do only one thing, and all of these things together fall under a single logical grouping, is overkill (IMO). I would suggest taking a good look at the business process your trying to model - the groupings (if any) should be readily apparent.

I would recommend Juval Lowry's book Programming WCF Services: Mastering WCF and the Azure AppFabric Service Bus - it's considered the WCF bible by many, and he has a whole appendix that's a good primer on SOA.