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A lot of time and effort has gone into making Awe, including a lot of back-and-forth about the best way to build it. Here I document some of the design decisions, both as a reminder for myself and to explain the thinking behind it to others.
Specific- not general-purpose
Awe was created to make it easier for the team at Alberon, a web/software development agency, to manage many different websites and web apps. Unlike Grunt, Gulp and others, it is not designed to be a general-purpose task runner or build tool, but to perform specific tasks well.
Before building Awe I tried using Grunt. This required me to install Grunt and all the plugins I was using in each project, upgrade each project separately when new versions were released, and keep the Gruntfiles in sync so every project had the latest features & fixes as I added them. This was tedious enough with 3 projects -- if it were expanded to all 25+ ongoing projects it would be a nightmare. So Awe is designed to be installed (and upgraded) only once, system-wide.
CoffeeScript, Compass, etc. are also installed system-wide, so every project must use the same version. In the future this could be changed to allow specific versions to be required for each project, and Awe would install/upgrade them for each project automatically (in the
.awe/ hidden directory). However, I would need to be convinced that this was better than just upgrading all projects at once -- e.g. a non-backwards compatible change.
Because Awe is installed system-wide, backwards compatibility is especially important. So we have plenty of unit tests to ensure nothing breaks.
"Backwards compatible" doesn't mean completely identical build output -- for example, adding source maps meant adding extra comments to the build files, but they are still backwards compatible.
Future-proofing is also important for the same reason, so the default settings are quite conservative -- features must be explicitly enabled in the config file, even if they are strongly recommended (e.g. Autoprefixer). Only features that are not expected to cause any problems (e.g. source maps) are enabled by default.
To ensure consistency between sites, only a minimum amount of configuration is allowed. It is limited to:
- Choosing the functionality to use (see above), and
- Allowing for necessary differences between projects (e.g. assets are different directories depending on the framework/CMS used)
In particular, config options should not be added to avoid making a decision about the best solution.
Many systems allow configuration files to be written in code (e.g. Gruntfile.js). While this allows more advanced customisation, I wanted to ensure consistency between sites and keep the configuration simple, which means limiting the options available.
If any extra functionality is required, it should be added to Awe itself, not added through custom project-specific code. This ensures it can be reused in other projects.
I may add hooks that can be called at certain points (on build, on deploy, etc.) when custom functionality is truely needed. These would most likely be external scripts (which can be written in any language) rather than Node.js functions.
Automatic mapping of asset files
There are no configuration options for how assets are built -- the idea is anyone should be able to look at the source files and work out what the resulting build files will look like. This is especially important when working with frontend (HTML/CSS) developers who are not programmers, work on a lot of different projects and just want it to work.
YAML import files
In an early alpha version of Awe, I used symlinks and :ref:`combined directories <combined-directories>` to merge vendor files with custom files. However, when viewing the directory over the network using Samba it was impossible to see which files were symlinks, therefore impossible to tell which files were custom and which were external (e.g. Bower packages). So symlink support was removed in favour of :ref:`YAML import files <yaml-import>`.
No shorthand syntax in import files
In the :ref:`YAML import files <yaml-import>` you must always use a list, even if there is only one entry:
You cannot shorten it to:
This is to avoid confusing the user when they try to add a second entry to the file.
Limited file type support
Awe doesn't support the shorthand Sass syntax (
.sass files), Less or several other languages purely because we (Alberon) don't currently use them. If we do decide to use them, we can add support for them in the future.
I would consider switching to a plugin-based architecture, more like Grunt, as long as Awe installed and upgraded them automatically in response to config options -- i.e. it would not require the user to run
npm install manually -- and it didn't require any complicated configuration (unlike Grunt & Gulp).
Although Awe has a limited target audience, it is open source to allow other people to use it -- particularly if a third-party takes over maintenance of a site/app we built. If anyone else wants to use it or improve it, that's absolutely fine. (Please do share your changes!)
Flag deprecated features
If any features are deprecated in the future, Awe should warn the user whenever they are used and suggest an alternative. There should be no way to disable these warnings. This will ensure that most projects are upgraded early, so they do not break if that feature is eventually removed.
Runs in a terminal (SSH)...
... not locally on Windows
Most of us at Alberon develop on Windows but use a Linux development server, editing files over a Samba network drive. This means a local GUI application would not be able to watch for file changes efficiently (e.g. see Prepros).
... not through a web server
Another option was to have it run automatically through the web server, rebuilding the files whenever they were requested -- similar to Rails' asset pipeline. This would have the advantage that it wouldn't be necessary to run Awe over SSH (which easy to forget if you're not used to it). However:
- It's more difficult to display errors this way (especially in CSS files)
- There's not always a 1-to-1 mapping of source to build files, making efficient compilation difficult
- It's slower to detect changed files, as they must be searched for each file loaded
- It would require more setup for each site
... not in a browser (web app)
Another option would be to build an application frontend that runs in the browser and communicates with a server process using WebSockets. This would be a more friendly interface for less technical frontend developers, but require significant extra work to implement.
None of these are three options are impossible, but the industry seems to be moving toward command-line build tools anyway, so that seemed like the best solution for now.
Both asset building and deployment
Deployment is not yet available, but is planned for a future release.
I considered splitting asset building and deployment into two separate applications, so they could be installed independently, but:
- Awe is not meant to be a general-purpose build tool that many people use, so the benefits would be limited
- It's easier for me to maintain a single application than several smaller ones
- Combining them will make it easier to minify/compress assets as part of the deploy process