![]() You don’t need to encourage (or nag!) developers to use an onion architecture it happens automatically as a side effect of the FP approach. They are very easy to test (deterministic!) and easy to understand without drilling into their implementation (no side effects!). A pure function is deterministic (a given input always results in the same output) and has no side effects (such as mutation or I/O). This is why the compositional approach is so appealing: Workflows are designed and built as independent units, containing just the functionality they need, yet we can still harness all the benefits of reuse and componentization when we need to.įinally, functional programmers try to use pure functions as much as possible. If we really do need exactly the same functionality within different workflows, that functionality can be defined once as a subfunction and then reused as a shared step in the workflows that need it. As we add new features to our system, the functionality required for each new workflow is defined independently, rather than grouped into a database or services layer. There is no need for a traditional layered architecture. ![]() This compositional approach means we only combine the specific components we need for a particular business workflow. Branching and other kinds of complexity may come into play, but even as workflows get larger and more complicated, the data always flows in one direction. Each of these steps can in turn be treated as a smaller function. The result is another function that can be used as a starting point for yet more composition.Ĭomposition is such an important concept that functional programmers have a suite of standard tools, such as monads, that allow for composition even if the inputs and outputs don’t quite match.įrom an architectural perspective, the most obvious consequence of composing bigger functions from smaller ones is that functional systems tend to look like pipelines with inputs and outputs, rather than a message-oriented request/response model.Įach workflow function generally has the same structure: Data is read, business decisions are made and data transformed as needed, and, finally, any new data or events are output at the other end. Two simple functions can be composed just by connecting the output of one to the input of another. Second, composition is the primary way to build systems. Just as functions are “things” at the coding level, these workflows are things at the architectural level, and the basic building blocks of the architecture. Each workflow represents a unit of functionality-a feature, use case, scenario, story, or whatever you want to call it. In a functional architecture, the basic unit is also a function, but a much larger business-oriented one that I like to call a workflow. They can be assigned to variables, stored in lists, passed as parameters, returned as results, and so on. That is, they can be treated just like other standalone values, such as integers and strings. The first is that functions are standalone values. Three principles of functional programming are especially relevant to software architecture. ![]() ![]() The principles of FP applied to software architecture ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |