Revision as of 08:37, 23 October 2007

Alpine Configuration Framework

The Alpine Configuration Framework (ACF) is a mvc-style application for configuring an Alpine device. The primary focus is for a web interface - ACF's main goal is to be a light-weight MVC "webmin".

Why Haserl + Lua

Other competitors in the arena were Webmin, Ruby on Rails, PHP with templates.

A full webmin (Perl), RoR or PHP implementation each require several MB of installed code, and can have very slow startup times, especially when used in "cgi" mode. After evaluating many options, we found that Lua has the following advantages:

It is small (typically ~200KB of compiled code)
It compiles and runs much faster than PHP, Perl or Ruby
It provides a "normal" scripting language with features similar to PHP, perl, java, awk, etc.

Haserl + Lua provides a 'good enough' toolset to build a full-featured web application.

Why ACF is MVC

The MVC design pattern is used to separate presentation information from control logic. By MVC we mean:

Model - code that reads / writes a config file, starts / stops daemons, or does other work modifying the router.
View - code that formats data for output
Controller - code that glues the two together

Note the lack of words like: HTML, XML, OO, AJAX, etc. The purpose of ACF's MVC is simply to separate the configuration logic from the presentation of the output.

The flow of a single transaction is:

start -> execute requested function in controller, optionally reading/writing a file using functions in the model -> execute the view to format the output -> end

Every transaction follows this pattern. For ACF developers, the focus should be on getting a model that does a proper job of abstracting the config file into useable entities and then building a controller that presents useable "actions" based on the model. The presentation layer should be last on the priority list.

ACF Developer's Guides

Introduction to the mvc.lua core module (The lua module that is at the core of ACF.)

ACF core principles (Things that are standard across the application)

@@ Line 11: / Line 11: @@
 * It is small (typically ~200KB of compiled code)
 * It compiles and runs much faster than [http://shootout.alioth.debian.org/gp4/benchmark.php?test=all&lang=lua&lang2=php PHP], [http://shootout.alioth.debian.org/gp4/benchmark.php?test=all&lang=lua&lang2=perl Perl] or [http://shootout.alioth.debian.org/gp4/benchmark.php?test=all&lang=lua&lang2=ruby Ruby]
-* It provides a "normal" scripting language with features similar to PHP, perl, java, awk, etc.
+* It provides a "normal" scripting language with [http://en.wikipedia.org/wiki/Lua_(programming_language)#Features features] similar to PHP, perl, java, awk, etc.
 Haserl + Lua provides a 'good enough' toolset to build a full-featured web application.