luvi

A project in-between luv and luvit.

The goal of this is to make building luvit and derivatives much easier.

Workflow

Luvi has a somewhat unique, but very easy workflow for creating self-contained binaries on systems that don't have a compiler.

# Make a folder
git init myapp
# Write the app
vim myapp/main.lua
# Run the app
luvi myapp
# Build the binary when done
luvi myapp -o mybinary
# Run the new self-contained binary
./mybinary
# Deploy / Publish / Profit!

Main API

Your main.lua is run in a mostly stock luajit environment with a few extra things added. This means you can use the luajit extensions including DLUAJIT_ENABLE_LUA52COMPAT features which we turn on.

LibUV is baked in.

The "uv" module contains bindings to libuv as defined in the luv project. Simply require("uv") to access it.

Use this for file I/O, network I/O, timers, or various interfaces with the operating system. This lets you write fast non-blocking network servers or frameworks. The APIs in luv mirror what's in libuv allowing you to add whatever API sugar you want on top be it callbacks, coroutines, or whatever.

Just be sure to call uv.run() and the end of your script to start the event loop if you want to actually wait for any events to happen.

local uv = require('uv')

local function setTimeout(timeout, callback)
  local timer = uv.new_timer()
  local function ontimeout()
    print("ontimeout", self)
    uv.timer_stop(timer)
    uv.close(timer)
    callback(self)
  end
  uv.timer_start(timer, timeout, 0, ontimeout)
  return timer
end

setTimeout(1000, function ()
  print("This happens later")
end)

print("This happens first")

-- This blocks till the timer is done
uv.run()

Integration with C's main function.

The raw argc and argv from C side is exposed as a zero indexed lua table of strings at args.

print("Your arguments were", args)

The "env" module provides read/write access to your local environment variables via env.keys, env.get, env.put, env.set, and env.unset.

local env = require('env')

-- Convert the module to a mutable magic table.
local environment = setmetatable({}, {
  __pairs = function (table)
    local keys = env.keys()
    local index = 0
    return function (...)
      index = index + 1
      local name = keys[index]
      if name then
        return name, table[name]
      end
    end
  end,
  __index = function (table, name)
    return env.get(name)
  end,
  __newindex = function (table, name, value)
    if value then
      env.set(name, value, 1)
    else
      env.unset(name)
    end
  end
}))

If you return an integer from main.lua it will be your program's exit code.

Bundle I/O

If you're running from a unzipped folder on disk or a zipped bundle appended to the binary, the I/O to read from this is the same. This is exposed as the bundle property in the "luvi" module.

local bundle = require("luvi").bundle
local files = bundle.readdir("")

bundle.stat(path)

Load metadata about a file in the bundle. This includes type ("file" or "tree"), mtime (in ms since epoch), and size (in bytes).

If the file doesn't exist, it returns nil.

bundle.readdir(path)

Read a directory. Returns a list of filenames in the directory.

If the directory doesn't exist, it return nil.

bundle.readfile(path)

Read the contents of a file. Returns a string if the file exists and nil if it doesn't.

Utils

There is also a "utils" module that has some useful debugging stuff like a colorized pretty printer.

local uv = require('uv')
local dump = require('utils').dump
-- Create a global p() function that pretty prints any values
-- to stdout using libuv's APIs
_G.p = function (...)
  local n = select('#', ...)
  local arguments = { ... }

  for i = 1, n do
    arguments[i] = dump(arguments[i])
  end

  local toWrite = table.concat(arguments, "\t") .. "\n"
  uv.write(stdout, toWrite);
end

Building from Source

We maintain several binary releases of luvi to ease bootstrapping of lit and luvit apps.

The following platforms are supported:

• Windows (amd64)
• FreeBSD 10.1 (amd64)
• Raspberry PI Raspbian (armv6)
• Raspberry PI 2 Raspbian (armv7)
• Ubuntu 14.04 (x86_64)
• OSX Yosemite (x86_64)

If you want to not wait for pre-built binaries and dive right in, building is based on CMake and is pretty simple.

First clone this repo recursively.

git clone --recursive git@github.com:luvit/luvi.git

Then run the makefile inside it. (Note this assumes you have cmake in your path.) If you're on windows, there is a make.bat file that works mostly like the unix Makefile.

cd luvi
make
make test

When that's done you should have a shiny little binary in build/luvi.

$ ls -lh build/luvi
-rwxr-xr-x 1 tim tim 948K Nov 20 16:39 build/luvi

Usage

Run it to see usage information:

$ luvi -h

Usage: luvi bundle+ [options] [-- extra args]

  bundle            Path to directory or zip file containing bundle source.
                    `bundle` can be specified multiple times to layer bundles
                    on top of eachother.
  --version         Show luvi version and compiled in options.
  --output target   Build a luvi app by zipping the bundle and inserting luvi.
  --main path       Specify a custom main bundle path (normally main.lua)
  --help            Show this help file.
  --                All args after this go to the luvi app itself.

Examples:

  # Run an app from disk, but pass in arguments
  luvi path/to/app -- app args

  # Run from a app zip
  luvi path/to/app.zip

  # Run an app that layers on top of luvit
  luvi path/to/app path/to/luvit

  # Bundle an app with luvi to create standalone
  luvi path/to/app -o target
  ./target some args

  # Run unit tests for a luvi app using custom main
  luvi path/to/app -m tests/run.lua

You can run the sample repl app by doing:

build/luvi samples/repl.app

Ot the test suite with:

build/luvi samples/test.app

CMake Flags

You can use the predefined makefile targets if you want or use cmake directly for more control.

WithOpenSSL (Default: OFF)      - Enable OpenSSL Support
WithOpenSSLASM (Default: OFF)   - Enable OpenSSL Assembly Optimizations
WithSharedOpenSSL (Default: ON) - Use System OpenSSL Library
                                  Otherwise use static library

OPENSSL_ROOT_DIR                - Override the OpenSSL Root Directory
OPENSSL_INCLUDE_DIR             - Override the OpenSSL Include Directory
OPENSSL_LIBRARIES               - Override the OpenSSL Library Path

Example (Static OpenSSL):

cmake \
  -DWithOpenSSL=ON \
  -DWithSharedOpenSSL=OFF \
  ..

Example (Shared OpenSSL):

cmake \
  -DWithSharedOpenSSL=ON \
  -DWithOpenSSL=ON \
  -DOPENSSL_ROOT_DIR=/usr/local/opt/openssl \
  -DOPENSSL_INCLUDE_DIR=/usr/local/opt/openssl/include \
  -DOPENSSL_LIBRARIES=/usr/local/opt/openssl/lib \
  ..

Holy Build

Executables across Linux distributions are not largely portable for various differences. We can leverage the holy-build-box to create a portable executable for i686 and x86_64 environments.

Note: If you are attempting this on OSX, please install GNU tar from homebrew:

brew install gnu-tar

To get started:

1. Create a docker machine:

docker-machine create --driver vmwarefusion --vmwarefusion-cpu-count 3 holy-build-box
eval $(docker-machine env holy-build-box)

2. Start the build

make linux-build

3. Results should be the current working directory.