mask is a CLI task runner which is defined by a simple markdown file. It searches for a maskfile.md in the current directory which it then parses for commands and arguments.
A maskfile.md is both a human-readable document and a command definition! Being documentation focused allows others to easily get started with your project's development setup by simply reading your maskfile.md. A nice advantage of using markdown is that syntax highlighting for code blocks is built-in to many editors and renderers like GitHub itself.
Here's the maskfile.md that mask itself uses as an example!
To get started, follow the guide below or check out the more advanced features mask has like positional args, optional flags, subcommands, other scripting runtimes and more!
Getting started
Currently, mask is only published to crates.io which allows you to install it with cargo.
maskis built with rust, so you'll need the rust toolchain installed if you don't have it already.
If you prefer to build from source, clone this repo and then run
cargo build --release
Next, define a simple maskfile.md in your project.
~~~sh
echo "building project..."
~~~
You can also write documentation anywhere you want. Only certain types of markdown patterns
are parsed to determine the command structure.
Note this code block below is defined as js. So far, mask supports node,
python, ruby and php as scripting runtimes!
~~~js
console.log("running project's tests")
~~~
And finally, try running one of your commands!
Features
Positional arguments
These are defined beside the command name within (round_brackets). They are required arguments that must be supplied for the command to run. Optional args are coming soon. The argument name is injected into the script's scope as an environment variable.
Example:
~~~bash
echo "Testing $test_case in $file"
~~~
Optional flags
You can define a list of optional flags for your commands. The flag name is injected into the script's scope as an environment variable.
Important to note that mask auto injects a very common boolean flag called verbose into every single command even if it's not used. This saves a bit of typing for you! This means every command implictly has a -v and --verbose flag already. The value of the $verbose environment variable is either "true" or simply unset/non-existent.
Example:
**OPTIONS**
* * * *
~~~sh
PORT=${port:-8080} # Set a fallback port if not supplied
if [[ "$verbose" == "true" ]]; then
fi
python -m SimpleHTTPServer $PORT
~~~
You can also make your flag expect a numerical value by setting its type to number. This means mask will automatically validate it as a number for you. If it fails to validate, mask will exit with a helpful error message.
Example:
**OPTIONS**
* * * *
~~~sh
TAX=${tax:-1} # Fallback to 1 if not supplied
echo "Total: $(($price * $TAX))"
~~~
Subcommands
Nested command structures can easily be created since they are simply defined by the level of markdown heading. H2 (##) is where you define your top-level commands. Every level after that is a subcommand. The only requirement is that subcommands must have all ancestor commands present in their heading.
Example:
~~~bash
echo "Starting service $service_name"
~~~
~~~bash
echo "Stopping service $service_name"
~~~
~~~bash
echo "Stopping everything"
~~~
Support for other scripting runtimes
On top of shell/bash scripts, mask also supports using node, python, ruby and php as scripting runtimes. This gives you the freedom to choose the right tool for the specific task at hand. For example, let's say you have a serve command and a snapshot command. You could choose python to serve a simple directory and maybe node to run a puppeteer script that generates a png snapshot of each page.
Example:
Valid lang codes: sh, bash, zsh, fish
The fallback is sh for unknown language codes.
~~~zsh
echo "Hello, $name!"
~~~
Valid lang codes: js, javascript
~~~js
const { name } = process.env;
console.log(`Hello, ${name}!`);
~~~
Valid lang codes: py, python
~~~python
import os
name = os.getenv("name", "WORLD")
print("Hello, " + name + "!")
~~~
Valid lang codes: rb, ruby
~~~ruby
Automatic help and usage output
You don't have to spend time writing out help info manually. mask uses your command descriptions and options to automatically generate help output. For every command, it adds -h, --help flags and an alternative help <name> command.
Example:
All output the same help info:
mask-services-start
Start or restart a service.
USAGE:
mask services start [FLAGS] <service_name>
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
-v, --verbose Sets the level of verbosity
-r, --restart Restart this service if it's already running
-w, --watch Restart a service on file change
ARGS:
<service_name>
Running mask from within a script
You can easily call mask within scripts if you need to chain commands together. However, if you plan on running mask with a different maskfile, you should consider using the $MASK utility instead which allows your scripts to be location-agnostic.
Example:
~~~sh
mask install
mask build
mask link
$MASK db migrate
$MASK start
~~~
Inherits the script's exit code
If your command exits with an error, mask will exit with its status code. This allows you to chain commands which will exit on the first error.
Example:
~~~sh
mask test \
~~~
Running mask with a different maskfile
If you're in a directory that doesn't have a maskfile.md but you want to reference one somewhere else, you can with the --maskfile <path_to_maskfile> option.
Example:
Tip: Make a bash alias for this so you can call it anywhere easily
# Call it something fun
# You can run this from anywhere
Environment variable utilities
Inside of each script's execution environment, mask injects a few environment variable helpers that might come in handy.
$MASK
This is useful when running mask within a script. This variable allows us to call $MASK command instead of mask --maskfile <path> command inside scripts so that they can be location-agnostic (not care where they are called from). This is especially handy for global maskfiles which you may call from anywhere.
$MASKFILE_DIR
This variable is an absolute path to the maskfile's parent directory. Having the parent directory available allows us to load files relative to the maskfile itself which can be useful when you have commands that depend on other external files.
Upcoming features
Use cases
Here's some example scenarios where mask might be handy.
Project specific tasks
You have a project with a bunch of random build and development scripts or an unwieldy Makefile. You want to simplify by having a single, readable file for your team members to add and modify existing tasks.
Global system utility
You want a global utility CLI for a variety of system tasks such as backing up directories or renaming a bunch of files. This is easily possible by making a bash alias for mask --maskfile ~/my-global-maskfile.md.
FAQ
Windows support?
Currently, this is unknown. I'm pretty sure the executor logic will need to be adjusted for Windows. Git Bash and Ubuntu on Windows have been reported to work but they are not actively being tested.
Is mask available as a lib?
mask was designed as a lib from the beginning and is accessible. However, it's very undocumented and will need to be cleaned up before it's considered stable.
Where did the inspiration come from?
I'm definitely not the first to come up with this idea of using markdown as a CLI structure definition.
My frustrations with make's syntax is what led me to search for other options. I landed on just for awhile which was a pretty nice improvement. My favourite feature of just is its support for other language runtimes, which is why mask also has this ability! However, it still didn't have some features I wanted like nested subcommands and multiple optional flags.
At some point in my searching, I came across maid which is where most of the inspiration for mask comes from. I thought it was brilliant that markdown could be used as a command definition format while still being so readable.
So why did I choose to rebuild the wheel instead of using maid? For one, I preferred installing a single binary, like just is, rather than installing an npm package with hundreds of deps. I also had a few ideas on how I could improve upon maid which is why mask supports multiple levels of nested subcommands as well as optional flags and positional args. Also... I just really wanted to build another thing with Rust :)
I also need to mention clap and pulldown-cmark which are really the core parts of mask that made it so easy to create.
Contributing
Check out our Contribution Guidelines before creating an issue or submitting a PR 🙌
Also, please review and follow the rules within our Code of Conduct 🙂
Author
Jake Deichert with the help of contributors.
@jakedeichert on Twitter · Website