Yadah

Yadah helps building services by organising the "data layer" into "subsystems" and "domains".

The @yadah/yadah package re-exports modules from all the core Yadah packages to simplify package installation and usage.

Usage

npm install -w @myscope/package-name @yadah/yadah

A typical "data layer" package will have a folder structure like:

src/
  models/
    index.js
    Bar.js
    Foo.js
  domains/
    index.js
    Bar.js
    Foo.js
  index.js
  config.js

The src/index.js file is responsible for creating subsystem instances and initialising the "Yada domains classes" via the DataManager.

// packages/package-name/src/index.js
import {
  createContext,
  createKnex,
  createLogger,
  createMessageQueue,
  createPubSub,
  createSchedule,
  DataManager,
  Model,
} from "@yadah/yadah";
import config from "./config.js";
import * as modelModules from "./models/index.js";
import * as domainModules from "./domains/index.js";

// setup subsystems
export const models = modelModules;
export const context = createContext();
export const knex = createKnex(config.knex);
export const logger = createLogger(config.logger);
export const mq = createMessageQueue(knex, logger);
export const pubsub = createPubSub(knex, config.pubsub);
export const schedule = createSchedule(knex, logger, config.schedule);

// initialise the data manager
const dataManager = new DataManager({
  models,
  context,
  knex,
  logger,
  mq,
  pubsub,
  schedule,
});

// boot domains
export const domains = dataManager.boot(domainModules);

// lifecycle functions allow services to cleanly control startup and shutdown
export const startup = async () => {
  Model.knex(knex);
  await dataManager.startup();
};
export const shutdown = async () => {
  await dataManager.shutdown();
  await knex.destroy();
};

Other packages may then access subsystems and domains classes from this package.

import { domains, logger } from "@myscope/package-name";

const foo = await domains.Foo.find(123);
logger.info("message", foo);

data-manager

https://www.npmjs.com/package/@yadah/data-manager

class DataManager

Manages subsystems and domain classes

class Domain

Base Yadah domain class implemenation

domain-critical-section

https://www.npmjs.com/package/@yadah/domain-critical-section

CriticalSectionMixin

A mixin for Yadah domain classes providing a way to shutdown processes cleanly.

domain-listener

https://www.npmjs.com/package/@yadah/domain-listener

ListenerMixin

A mixin for Yadah domain classes to manage registering event listeners.

domain-model

https://www.npmjs.com/package/@yadah/domain-model

class Model

An Objection.js Model with plugins that provide functionality required by the ModelMixin service class mixin.

ModelMixin

A mixin for Yadah domain classes that provides access to an Objection.js Model.

class NotUniqueError

A Error class that may be thrown by ModelMixin when a query does not validate as having a unique result.

NotUniqueMixin

A mixin for Objection.js models which adds a .throwIfNotUnique() function to query builder instances.

subsystem-context

https://www.npmjs.com/package/@yadah/subsystem-context

createContext

A function to create a "context" subsystem.

ContextMixin

A mixin for Yadah domain classes which provides access to the service's context subsystem.

subsystem-knex

https://www.npmjs.com/package/@yadah/subsystem-knex

createKnex

A function to create a knex instance.

KnexMixin

A mixin for Yadah domain classes which provides access to the service's knex instance.

TRANSACTION

A symbol used to lookup the current knex transaction in a promise-chain context.

TransactionMixin

A mixin for Yadah domain classes which allows creating database transactions.

subsystem-logger

https://www.npmjs.com/package/@yadah/subsystem-logger

createLogger

A function to create a logger subsystem.

LoggerMixin

A mixin for Yadah domain classes which provides access to the service's logger subsystem.

subsystem-message-queue

https://www.npmjs.com/package/@yadah/subsystem-message-queue

createMessageQueue

A function to create a message queue (mq) subsystem.

MessageQueueMixin

A mixin for Yadah domain classes which provides access to the message queue subsystem, and helper methods for adding jobs to the queue.

subsystem-pubsub

https://www.npmjs.com/package/@yadah/subsystem-pubsub

createPubSub

A function to create a PubSub subsystem.

PubSubMixin

A mixin for Yadah domain classes which provides access to the pubsub subsystem, and helper methods for publishing messages.

subsystem-schedule

https://www.npmjs.com/package/@yadah/subsystem-schedule

createSchedule

A function to create a schedule subsystem.

ScheduleMixin

A mixin for Yadah domain classes which allows registering scheduled jobs.

subsystem-storage

https://www.npmjs.com/package/@yadah/subsystem-storage

createStorage

A function to create a Storage subsystem.

StorageMixin

A mixin for Yadah domain classes which provides access to the storage subsystem.