distage is a pragmatic module system for functional Scala, it aims to combine simplicity and expressivity of pure FP with the flexibility and extreme late-binding that’s traditionally associated with object-oriented dependency injection frameworks, such as Guice.
- Faster applications and tests:
distageguarantees that no unnecessary instantiations will happen during your tests or application startup.
- Quick failure detection:
distageperforms all the integration checks for your application and tests even before any instantiations happened.
- Simple tests:
distageeliminates all the hard work of setting up your test environments, especially configurable ones.
- Better integration tests:
distageprovides you great memoization support for your tests so you may reuse expensive resources (like database connections) across multiple integration tests, gaining performance and without sacrificing correctness.
- Simple development workflow: distage-framework module allows you to develop Role-Based Applications – a fusion of Microservices and Monoliths. You may run all your services in one process for development purposes (and even switch to mock implementations with a single commandline argument).
- Fast compile times and low mental overhead: Unlike fully compile-time DIs,
distagedoes not impose a compile time penalty.
distageextensions are simple to write and do not require type-level programming.
- Simple debugging:
distageprovides you important insights about your application and allows you to introspect and modify it on the fly, before any instantiations happen.
- High Correctness:
distagesupports resources and lifecycle natively and guarantees proper cleanups even when something went wrong.
- No reflection:
distagegenerates all constructors and type info at compile-time and does not use Scala reflection. As such, it’s compatible with Graal Native Image and (soon) Scala.js.
distageis designed to not impact the way your Scala code is written. It just removes all the initialization boilerplate. You don’t need to learn magic tricks to write components in a distage application.
distage is recommended by industry leaders:
Given its native support for type classes and higher-kinded types – both features indispensable to functional programming – distage is one of the leading dependency injection libraries out there. Bonus points for being built by a wicked-smart team that contributes to ZIO!
-? John A. De Goes
Q: How to pronounce
Q: Isn’t it unsafe to use runtime dependency injection?
distage is split into two stages, first a wiring
plan is calculated, only afterwards it is executed. This
Plan value can be tested for errors in an ordinary test suite ? if it is well-formed, the wiring will succeed at runtime. This test can also be performed at compile-time ?
distage-framework module contains macros for aborting compilation in case of erroneous wiring.