development-steps.md

Source code under lib/ folder is transpiled based on the bl code we have written.

It contains our application and domain layers. Each application handler/use-case is injected some ports which are associated with a token. This token will be used to attach the concreted adapter.

Every folder under bitloops/ is a nestjs plugin, and can be assumed to be a npm package.

Add config/ folder and define some initial configuration for your app. e.g. http_port, host etc. You will be adding database, apiKeys, secrets and so on there later based on your adapters. yarn add @nestjs/config. Create a .development.env file and gitignore it.

Project structure

We start with 2 root modules. The api module, which contains all the controllers and acts as our application gateway, and the app module which is a modular monolith containing all our modules(with their infra, application & domain layers). We need to write the api code, and the infra code for each module(with concretions of each port used by application layers).

Api module

Each controller will have injected the commandBus or/and the queryBus from the bus-plugin you will be using. On api.module.ts we register the controllers, and as imports the buses-plugin, the auth-module plugin and nest' config module if we need it. Each controller dispatches a command/query using the appropriate bus and then handles the response matching each error to the appropriate response code.

• grpc yarn add @grpc/grpc-js google-protobuf

App module

We will be registering each bl module, connecting it with its required adapters. We can place this code under src/bounded-contexts/[bounded-context-name]/[module-name]/.

Each bl module is a dynamic module, so when we import it, we need to pass the injected modules & adapters(nestjs providers) as arguments.

Tracing

We can trace the execution of a method by using the @Traceable decorator provided by the bitloops-tracing plugin. Let's say we want to use it on the api module to trace the duration of a addTodo post http route. First we have to register the plugin in the api.module.ts. After that we just decorate the method we want.

  @OtherDecorators...
  @Traceable()
  async addTodo() {
    // Controller logic
  }

We can also trace the execution of a repo method, or any adapter we have concreted in the same way.

  @OtherDecorators...
  @Traceable()
  async save(entity: Entity) {
    // ...
  }