Software Development Detox Part 2: Remote Procedure Calls

We've seen in our first detox installment that it is detrimental to maintain the state of the conversation between participating parties. The conversation that may have occurred between the interested parties and a targeted resource may have affected the state of the targeted resource. But that doesn't mean that the various stages of the conversation itself need to be retained.

Today we'll look into another form of software intoxication; this one has to do with how is the conversation implemented.

Typically, when two or more parties get engaged in a conversation, they tend to accomplish successful conversation by sending each other specific messages. For example, if an airplane is approaching the airport, the messaging between the pilot and the control tower gets peppered with code words such as "roger" and "over". That way, the conversation protocol gets established in the attempt to minimize the noise and maximize the signal.

In a loosely coupled world of business computing, free market forces dictate that many solutions providers can compete for the most successful solution. That situation creates a wild diversity of proposed conversation protocols. What's happening is that basically any vendor (i.e. solution provider) is free to come up with a completely arbitrary set of formal rules outlining how is the conversation going to take place. That creates a hell of a noise in the solution space, resulting in brittle and faulty implementations.

The culprit most of the time boils down to the methodology known as Remote Procedure Call (RPC). The remote procedure proposed by the vendor is a completely arbitrary, unilaterally constructed expression that the vendor expects the consumer to learn. In addition, the vendor reserves a unilateral right to change the expression encapsulated at the RPC level, and the consumer has no recourse but to re-learn the intricacies of how to talk to the vendor.

This unfortunate situation creates endless problems and headaches. All the consumers of the proposed vendor services are expected to keep an ever growing inventory of those custom Remote Procedures, and are on top of that left vulnerable to the future changes of that inventory.

Because of that, the effective detox therapy strongly advises against using the RPC model when architecting and designing your software solution. We will see in the next installment what is a much better way to go about accomplishing the robust software architecture.