micro-serverless

A micro serverless service (FaaS). Based on Node.js vm.

It provides a micro FaaS service allowing you to run, develop and manage application functionalities immediately without the complexity of building and deploying the infrastructure typically framework. Just upload your code and micro-serverless runs it for you. You can set up your code to automatically trigger from personal service or call it directly.

中文 Readme

Motivation

I wanted to build some simple personal assistant programs like weather tips, news feed or reminding me not to miss the game. And it's unnecessary to build several huge apps use Spring or complexity framework. a serverless service is proper I thought. So I made an uncomplicated and flexible serverless application with just-enough features.

Quick Start

$ npm i
$ npm run dev
$ open http://localhost:7001/

Example

You can find them in /src/fns/. your code should have an only function main(), this function will be trigger when request GET /vm/[filename], and the service response what you return in function main().

1. basic example

// function_a
async function main() {
  return 'Hello world!';
}

GET //127.0.0.1:7001/vm/function_a

Hello world

2. overtime

Function execution time is limited in 1.5s default or will throw the error. the Error response is a JSON with error.

// function_b
function main(ctx) {
  while (1) {}

  return 'Hello world!!';
}

GET //127.0.0.1:7001/vm/function_b

{
  "error": "Error: Script execution timed out after 1500ms at Script..."
}

3. Async function

You can run an asynchronous function by anyc and await. And use ctx.curl (Shortcut for the httpclient.curl) if you want to fetch anything. the ctx is passed by egg.js, you can find more API in egg.js context. Learn more about egg.js or koa.js.

Fetch an URL:

// function_c
async function main() {
  const { location } = ctx.query;

  const URL = `https://bing.com`;
  const data = await ctx.curl(URL, {
    dataType: 'json',
  });

  return { data } || {};
}

Sleep 1s:

// function_d
async function main() {
  const start = new Date().toLocaleTimeString();

  const end = await new Promise(resolve => {
    setTimeout(() => {
      resolve(new Date().toLocaleTimeString());
    }, 1000 * 1);
  });

  return {
    start,
    end,
  };
}

4. Build a Github Trending service

// github_trending
async function main() {
  const url = 'https://github-trending-api.now.sh/repositories';

  const res = await ctx.curl(
    'https://github-trending-api.now.sh/repositories',
    { dataType: 'json' },
  );

  return res.data.map(item => ({
    title: `${item.name} | 👨‍💻${item.author} | ⭐️${item.stars} | ${item.language}`,
    url: item.url,
    desc: item.description,
  }));
}

GET //127.0.0.1:7001/vm/github_trending

[
  {
    "title": "...",
    "url": "...",
    "desc": "..."
  },
  ...
]

5. Build a realtime Hacker news service

async function main() {
  const tops =
    (await ctx.curl(
      'https://hacker-news.firebaseio.com/v0/topstories.json?print=pretty',
      {
        dataType: 'json',
      },
    )) || [];

  let hnList = [];

  await Promise.all(
    tops.data
      .slice(0, 10)
      .map(item =>
        ctx.curl(
          `https://hacker-news.firebaseio.com/v0/item/${item}.json?print=pretty`,
          { dataType: 'json' },
        ),
      ),
  ).then(data => {
    hnList = data.map(item => ({
      title: item.data.title,
      url:
        item.data.url || `https://news.ycombinator.com/item?id=${item.data.id}`,
      info:
        `${item.data.score} points By ${item.data.by}` +
        `${new Date(item.data.time * 1000).toLocaleString()} | ` +
        `${item.data.descendants} comments`,
    }));
  });

  return hnList;
}

6. Check the weather by location.

You can run a function with parameters. In this case, Getting the data of weather according to a location by passed query in URL (//127.0.0.1:7001/vm/weather?location=Tokyo)

// weather.js

async function main() {
  const { location = 'New York' } = ctx.query;
  const url = `http://api.weatherstack.com/current?access_key=95f5ee664befefc1c49fa0dac0da19c7&query=${location}`;

  const res = await ctx.curl(url, { dataType: 'json' });

  return res.data;
}

GET //127.0.0.1:7001/vm/weather?location=Tokyo

FAQ

What can this project be used for ?

It‘s convenient to run some personal services, like checking the weather, finding the latest news and to-do list reminding, You can build yourself services on it easily and rapidly without concerning about infrastructure application, just need a function.

Can this project be used for production ?

I don't recommend you do this for two reasons: first is security, although vm guarantees a secure sandbox, it still exists risk, If you want to learn more about it, check the document vm API. for another, this micro serverless program hardly automatically scales with the size of the workload due to it was designed to run a simple personal assistant service on a personal device, So I didn't consider too much about the performance (In fact, the framework egg.js has done it a lot about performance and it "born to build enterprise apps", But I don't know exactly how the performance of vm, This requires more experiments to prove).

License

MIT License (MIT)