Ds-node-service NPM

ds-node-service

Base module for Deepstream RPC based Node services

Let's start with a comprehensive example:

import { createRpcService } from 'ds-node-service';
import joi from 'joi';

const name = 'service1';
const address = 'localhost:6020';
const credentials = { id: 'serviceId', password: 'secretPassword' };

// The API schema should actually rather be placed in a separate file.
const apiSchema = {
  doSomething: {
    description: 'Description for api-function that does something.',
    args: joi.object().keys({
      name: joi
        .string()
        .trim()
        .alphanum(),
      properties: joi
        .object()
        .unknown()
        .keys({
          birth: joi.date(),
        }),
    }),
    return: joi.number(), // joi-schema for return value or null if no return value
  },
};

// The implementation part would also rather have its own file.
function doSomething({ name, properties }) {
  // DB call or whatever
}
const implementation = {
  doSomething,
};

// Create service, register API (spec & implementation) and start the service.
async function main() {
  const service = createRpcService({
    name,
    address,
    runForever: true,
    credentials,
  });

  service.registerApi(apiSchema, implementation);

  await service.start();
}
if (require.main === module) main();

The base RPC service will on start():

Fetch credentials, if a credentialsUrl was provided, and merge the result with the directly specified credentials object.
Log in to deepstream with authParams = credentials
Provide (rpc.provide(..)) the RPC functions registered with registerApi.
Start an idle loop if runForever is true.

The API registration and service start will automatically add a getInterface function that will return an API specification with all methods with argument names & types. Example (from requesting client): client.rpc.make('service1/getInterface').

Some more explanatory comments on the example above:

The type assertion system is joi, that needs to be used in the API specification.
You can easily fetch Deepstream (for instance as an npm package) and start it locally on its default port 6020, thus localhost:6020 as address.