Lua plugins for MADS

This is a collection of plugins for MADS. The project creates the plugins lua_source.plugin, lua_filter.plugin, and lua_sink.plugin.

The plugins provide an interface to Lua scripts, allowing you to run Lua scripts from MADS.

This plugin has been updated for MADS v2

Supported platforms

Currently, the supported platforms are:

• Linux
• MacOS
• Windows

Installation

Linux and MacOS:

cmake -Bbuild -DCMAKE_INSTALL_PREFIX="$(mads -p)"
cmake --build build -j4
sudo cmake --install build

Windows:

cmake -Bbuild -DCMAKE_INSTALL_PREFIX="$(mads -p)"
cmake --build build --config Release
cmake --install build --config Release

INI settings

The plugin supports the following settings in the INI file:

[lua_source]
script_file = "source.lua"
search_paths = []

[lua_filter]
script_file = "filter.lua"
search_paths = []

[lua_sink]
script_file = "sink.lua"
search_paths = []

The script_file is Lua script file to run. The path can be:

• an absolute file path (e.g., /path/to/script.lua)
• a relative file path (e.g., ./script.lua)
• a file name (e.g., script.lua)

In the last two cases, the script is searched in the following directories, in this order:

1. the folder ./lua relative to the folder containing the current executable file
2. the folder ./scripts relative to the folder containing the current executable file
3. the folder ../lua relative to the folder containing the current executable file
4. the folder ../scripts relative to the folder containing the current executable file
5. the absolute path <INSTALL_PREFIX>/lua
6. the absolute path <INSTALL_PREFIX>/scripts
7. any other path in the search_path list, which bust be either absolute or relative to the executable file

Note that the executable file is typically the MADS plugin loader.

All settings are optional; if omitted, the default values are used. Note, however, that the section [lua_xxx] is mandatory (and can be empty).

Lua details

The lua script has the package search list set to the same directories above detailed, where lua scripts are loaded. If you need an additional library or scripts, just put it in one of those dirs and require it.

The Lua script has available the JSON library, loaded as json.

The Lua script defines the table MADS with the fields data and topic. These fields are automatically updated by the plugin upon receiving a new payload.

Source plugin (lua_source.plugin)

The Lua script must implement the function MADS:get_output(), which is called by the plugin obtaining a new payload. The function must return a JSON-formatted string (use json.encode(self.data)).

Filter plugin (lua_filter.plugin)

The Lua script must implement the function MADS:process(), which is called by the plugin for each payload. The function must return a JSON-formatted string (use json.encode(self.data)).

Sink plugin (lua_sink.plugin)

The Lua script must implement the function MADS:deal_with_data(), which is called by the plugin for each payload. The function must return nothing.

Note that the library ansicolors is available (but not loaded by default). If you need it, just require it in your script as local col = require("ansicolors").

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