Define the "prime" service

Now at this stage, we are going to define our first service. This service will have one service operation called getPrimeListFromRange which will calculate all the prime numbers in a given number range.

We want to do this because we want to share the workload across multiple identical services of prime and then combine the result later.

The prime service will receive these commands from the render service, calculate all the prime numbers up to that number, and send the result back to its render service.

Create Folder

Create a new folder called services/prime and cd into that folder:

mkdir -p services/prime && cd services/prime

Create File

Create the file which will contain the service you are going to initialize in the framework later. Each service definition is a collection of functions in an object:

touch index.js

Add Service Definitions

Paste the following code into the file you've just created. This is an example of a service definition. All services require a single service definition file containing an object which is the default export of that file.

That object simply needs to contain a list of named functions. Each one of these functions will receive the same parameters.

function getPrimeList(min, max) {
  const sieve = [];
  let i;
  let j;
  const primes = [];
  for (i = 2; i <= max; ++i) {
    if (!sieve[i]) {
      // i has not been marked -- it is prime
      if (i >= min) {
        primes.push(i);
      }
      for (j = i << 1; j <= max; j += i) {
        sieve[j] = true;
      }
    }
  }
  return primes;
}

module.exports = {
  getPrimeListFromRange: ({ sendSuccess, data }) => {
    const { start, end } = data.body;
    // Will calculate prime numbers for a given number range.
    const listOfPrimeNumbers = getPrimeList(start, end);
    // Send the result back to its source
    return sendSuccess({
      result: listOfPrimeNumbers,
    });
  },
};

Don't worry too much about the arguments in the above getPrimeListFromRange() operation. You can see all the parameters in the API Reference section of this documentation.

Back To Root

Back To Root:

cd ../..

Summary

The folder structure should have so far should look like this:

├── package.json
├── services
│   ├── prime
│   │   └── index.js
└── yarn.lock | package.json

If you have the tree command installed in your terminal you can check this by running:

tree -I "node_modules|cache|test_*'\n

Great work so far, just two more steps to go and we will have a fully build Risen.JS framework! Please continue to the next section...