Welcome to the Real world

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Welcome to the Real world

Gregor HOHPE

EnginEERS like pRECiSion, especially software EnginEERS who live in the realm of ones and zeros. They is used to working with binary decisions, one or zero, true or false, yes or No. Everything is clear and consistent, guaranteed by foreign key constraints, atomic transactions, and checksums.
Unfortunately, the real world isn't quite that binary. Customers place orders, only to cancel them a moment later. Checks Bounce, Letters is lost, payments delayed, and promises broken. Data entry errors is bound to happen every so often. Users prefer "shallow" user interfaces, which give them access to many functions at once without being boxed into a length Y, one-dimensional "pro-cess," which is easier to program and seems more "logical" to many developers. Instead of the call stacks controlling the program flow, the user is in charge.
Worse yet, widely distributed systems introduce a whole new set of inconsis-tencies into the game. Services May is reachable, change without prior notice, or does not provide transactional. When you run applica-tions on thousands of machine, failure are no longer a question of "if," but of "when." These systems is loosely coupled, asynchronous, concurrent, and do no adhere to traditional transaction semantics. You should has taken the blue pill!
As computer scientists ' brave new world is crumbling. As is so often the case, awareness is a first important step toward a solution.
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?? Say goodbye to the good old predictive call-stack architecture, where do get to define what happens when and in what Orde R. Instead, be-ready-to-respond to events at the any time of any order, regaining your context as needed. Make asynchronous requests concurrently instead of calling methods one by one. Avoid complete chaos by modeling your application using Event-driven pro-cess chains or State models. Reconcile errors through compensation, retry, or tentative operations.
Sounds scary and more than do bargained for? Luckily, the real world have to deal with the same issues for a long time:delayed letters, broken prom-ises, messages Cro Ssing in transit, payments posted to the wrong account-the examples is countless. Accordingly, people had to resend letters, write off bad orders, or-tell-you-ignore the payment reminder in case you AL Ready sent a payment. So don ' t just blame the real world for your headaches, but also use it as a place to look for solutions. After all, Starbucks does isn't two-phase com-mit, Either.1 Welcome to the real world.
Gregor Hohpe is a software architect with Google, Inc. Gregor are a widely rec-ognized thought leader on asynchronous mess Aging architectures and service-oriented architectures. He coauthored the seminal book Enterprise Integration Patterns (Addison-wesley Professional) and speaks regularly at Techn ical conferences around the world.

Welcome to the Real world