Mu

Mu is a framework for building serverless applications, APIs, and services. It combines the best of FaaS and PaaS to support a broad range of scenarios with minimal infrastructure.

Overview

Mu makes two major categories of serverless software easy to create and manage.

First, Mu enables lightweight API gateways. These are serverless web applications, used either to serve up web pages, expose REST APIs, or a combination of the two. Mu lets you express your endpoints and logic without needing to worry about the associated infrastructure (such as VMs, containers, web servers, and load balancers).

Second, Mu enables on-demand computations of multiple kinds. This includes batch tasks or streams processors, which can be initiated either by a time-based schedule or reactive event-based trigger.

Mu unifies how you author the logic for these scenarios, in addition to how you manage the associated software packages. Mu is polyglot, and supports many languages out of the box: Node.js, Go, Python, Java, and others. Mu is also cloud- neutral, supporting many execution environments: local/on-premise, AWS Lambda, Google Cloud Functions, and more.

Examples

Before diving into the details, let's see some Mu examples, written in Node.js.

Here is the simplest possible Mu program:

var mu = require("mu");
mu.func(function(req, res) { res.write("Hello, Mu!"); });

We have simply imported the "mu" package and registered a single callback function. Although this is a simple program akin to what AWS Lambda gives you, it doesn't showcase Mu's ability to manage whole serverless applications.

A more comprehensive Mu program might look something like this:

var mu = require("mu");

// 1. Functions
mu.func("hello", function(req, res) { res.write("Hello, Mu!"); });

// 2. Endpoints
//     - API routes
mu.http.get("/", function(req, res) {...});
mu.http.post("/login", function(req, res) {...});

//     - Static content
mu.http.get("/static", mu.mw.static("./static"));

// 3. Schedules
mu.daily(function(req, res) {...});

// 4. Triggers
mu.on(salesforce.customer.added, function(req, res) {...});
mu.on(marketo.customer.deleted, function(req, res) {...});

Now things have gotten interesting! This example demonstrates a few ways to register a serverless function:

1. Functions: The func routine registers a function with a name. Although they aren't automatically hooked up to anything, such functions can be invoked by handle or by name using the command line and web interfaces.

2. Endpoints: http exposes a HTTP endpoint using a standard route syntax. This can be used to create web pages or REST APIs using your favorite frameworks, deployed atop an entirely serverless architecture. The usual HTTP verbs are available -- like get and post -- and the response may be a custom serverless function or middleware. mu.static is a middleware function to serve static content such as HTML, CSS, and JavaScript.

3. Schedules: daily runs the given function once/day. The obvious relatives like hourly also exist, in addition to the general-purpose schedule function which accepts a cron-like schedule.

4. Triggers: Lastly, on subscribes to a named event -- there are many to choose from! -- and runs the function with its payload anytime that event occurs. Streams-based events that automatically batch are also available.

Installation