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Reventless — Framework Developer Guide

This guide is for contributors to the reventless-core package — the cloud-agnostic framework core that application developers build on top of.

If you are building an application with Reventless, see the App Developer Guide. If you are writing a new cloud provider adapter package, see the Infrastructure Guide.

What the Framework Is​

The reventless-core package defines:

  • Component module types (Aggregate.T, ReadModel.T, Plugin.T, etc.) — the contracts that all implementations must satisfy
  • Builder functors (Aggregate_Builder.Make, ReadModel_Builder.Make, etc.) — generic implementations parameterized over adapter interfaces
  • Adapter interfaces (EventLog_Adapter.Storage, CommandTopic_Adapter.Channel, etc.) — the contracts that cloud providers must implement
  • Spec types (Aggregate.Spec, ReadModel.Spec, etc.) — the contracts that application developers implement

The framework itself does not depend on any cloud provider. All infrastructure concerns are injected through adapter interfaces.

Repository Structure​

The monorepo has four package roots; framework packages live under reventless/. See the generated Packages page for the full, always-current list.

reventless/
├── reventless-spec/    # Type specs and shared interfaces (no impl)
├── reventless-core/    # Framework core (this package)
│   └── src/
│       ├── components/   # Component definitions and builders
│       │   ├── Aggregate/
│       │   ├── ReadModel/
│       │   ├── Plugin/
│       │   └── ...
│       ├── admin/        # Built-in Platform Admin components
│       └── adapter/      # Adapter interfaces and runtime builders
├── reventless-aws/     # AWS cloud provider implementation
└── reventless-local/   # Local (in-memory / SQLite) provider

Key Abstractions​

Component Structure Pattern​

Each component follows a consistent file structure — two required files (Component.res, Component_Builder.res) plus up to three optional ones (_Adapter, _Operations, _Callback). See Component Structure Pattern for the full breakdown and a walkthrough using EventLog as an example.

Pulumi.Output.t Wrapping​

All infrastructure values are wrapped in Pulumi.Output.t<'a>. This separates deploy-time values (which may not be resolved yet) from runtime values. Adapter interfaces return Pulumi.Output.t-wrapped values; the framework composes them using Pulumi.Output.apply.

Builder Pattern with Module Types​

Components use first-class modules and functors for type-safe configuration:

module type T = {
  module Spec: Reventless.Aggregate.Spec
  let make: (~opts: Pulumi.ComponentResource.options=?) => component
}

module Make = (Spec: Spec, Storage: Storage, Channel: Channel): T => { ... }

Where to Start​

  1. Contributing setup — clone, build, and run tests
  2. Framework internals — the ordered tour of how the framework fits together
  3. Component structure pattern — the file pattern used across all components
  4. Extending the framework — add a component or a provider adapter