ly

Introduction

Avoid YAML templating and use something to generate YAML, programmatically. This uses Lua (the programming language) to generate YAML file manifests. This is a self contain binary, no external dependencies needed.

Getting Started

Lua is simple. It supports strings, numbers, boolean, arrays, and maps.

1. Create a file called manifest.lua.

2. Give it the contents.

   return {name="Hello World"}
   

   The last expression of your manifest.lua file should always have a return statement of a hash or array (table type in Lua). You will receive in error if the type is incorrect.

   See the examples for more advance usage.

3. Invoke either from source or releases.

4. The stdout will be the following YAML payload.

   name: Hello World
   

null support

Lua has one quirk. If a table (array or hash) has a nil value entry it is no longer considered as contiguous entry in the table. This results in the outputted YAML not having a null entry.

To resolve this a null value was created in ly's lua runtime.

The following Lua:

return {name=null}

will render YAML as:

name: null

Installation

Source

The source uses go.mod for dependency management. Please ensure that golang version 0.12.x or higher is installed.

$ git clone https://github.com/jtarchie/ly
$ cd ly
$ go run ly/main.go -c examples/variable.lua
list_with_a_map:
- key1: value1
  key2: value2
- item2

Releases

1. Download the latest release.
2. Extract the binary from the .tar.gz file -- ie tar xzf ~/Downloads/ly_*.tar.gz.
3. Put it into an executable PATH -- ie chmod +x ~/Downloads/ly_* && mv ly_ /usr/local/bin/ly.
4. Run ly -c <your-lua-file>.lua