Sparrowdo is a Perl 6 project to facilitate automatic configuration of systems. There’s a repository of useful modules to make specific cases easier to work with, but the Core DSL can already take care of many tasks. In this tutorial, I’ll guide you through setting up Sparrowdo, bootstrapping it onto your local system, writing a task and running it.
Sparrowdo is a Perl 6 project, so you’ll need to have Perl 6 installed. We’ll also use the Perl 6 package manager zef to install Sparrowdo itself. Luckily for us, there’s a stable distribution of Perl 6 with everything we need added to it, called Rakudo Star. And to make it easier for GNU+Linux users, I wrote a tool to fetch the latest Rakudo Star release, compile it and install it, called LoneStar. Since this tutorial will aim at GNU+Linux users, I’ll use that to install Perl 6.
Installing Perl 6 with LoneStar
LoneStar is a Bash application to download, compile and set up Perl 6. It’s a
standalone application, meaning you don’t have to install it to your system. You
can just run it from the source directory. First, we’ll have to get the source
directory, which we’ll do using
mkdir -p ~/.local/src git clone https://github.com/tyil/lonestar.git ~/.local/src/lonestar cd !$
Now you have the LoneStar sources available in
~/.local/src/lonestar. You can
run the application using
./bin/lonestar. Running it, you’ll get some help
$ ./bin/lonestar lonestar - Installation manager for Rakudo Star Usage: lonestar <action> [arguments...] Actions: help [action] init [version=latest] install [version=latest] path [version=latest] reinstall [version=latest] upgrade
We’ll be needing the
install action to get Perl 6 installed, and the
action to configure the
$PATH environment variable. Depending on your
install may take a couple minutes as it will compile Rakudo Perl 6
and install some base modules. You might want to grab a drink during this
$ ./bin/lonestar install $ eval $(./bin/lonestar init) $ perl6 -v This is Rakudo Star version 2018.04.1 built on MoarVM version 2018.04.1 implementing Perl 6.c.
If there’s a newer version available of Rakudo Star, the version numbers given
Installing Sparrowdo with zef
Now that you have Perl 6 available and installed, you can continue on using
zef to install Sparrowdo.
zef is bundled with Rakudo Star, so you don’t have
to do anything to get it working.
zef install Sparrowdo
This will instruct
zef to install Sparrowdo and all its dependencies. This can
take a couple minutes, again depending on the hardware of your machine.
Bootstrapping your system
The first step to working with Sparrowdo is bootstrapping the system you wish to
use it with. In this case, that’ll be the local system. There’s a
option to do this automatically.
If you wish to bootstrap a remote system, you can use the
Now your system is ready to be configured automatically using Sparrowdo!
Sparrowfiles are the files that describe the tasks Sparrow should execute to
get you the configuration you want. They are valid Perl 6 code, and call the
subroutines (or sparrowtasks) that will handle the actual actions. By default,
sparrowdo, it will look for a file named
sparrowfile in the
To make our sample, we’ll create a new directory to work in, so we have clean
directory that can be shared easily. You can also keep this directory under
version control, so you can distribute the
sparrowfile with all its templates.
If you just want to create an empty directory to test things in, without
"polluting" the rest of your system, just call
I’ll be using
~/.local/sparrowdo/local-dns to work in, as I’ll be setting up a
local dns cache with dnsmasq for
the sample code.
As noted in the previous paragraph, for the sake of a demo I’ll guide you
through creating a
sparrowfile to install and configure
dnsmasq as a local
DNS cache. Using your favourite
$EDITOR, write the following to
package-install "dnsmasq"; directory "/etc/dnsmasq.d"; file-create "/etc/dnsmasq.conf", %(content => slurp "dnsmasq.conf"); file-create "/etc/dnsmasq.d/resolv.conf", %(content => slurp "resolv.conf"); service-start "dnsmasq";
sparrowfile will set up the following configuration for
/etc/dnsmasq.ddirectory in which we’ll store configuration files for
Create the configuration files
The configuration files will be created based on the configuration files in the
current directory. So for this to work, you’ll need to also create the
appropriate configuration files. Let’s start off with the main
listen-address=127.0.0.1 no-dhcp-interface= resolv-file=/etc/dnsmasq.d/resolv.conf
This will make
dnsmasq listen on the loopback interface, so it’ll only be able
to be used by the local machine. Furthermore, DHCP functionality will be
disabled, and the upstream resolvers are read from
The contents of that file are as follows:
nameserver 18.104.22.168 nameserver 22.214.171.124
These nameservers are part of the FreeDNS project. You
can of course use whatever other DNS provider you want to use as your upstream
servers. Now, for
dnsmasq to be used, you will also need to set your machine’s
DNS resolvers to point to the
dnsmasq service. This is defined in
/etc/resolv.conf, so lets append the following to our
sparrowfile to set
bash "chattr -i /etc/resolv.conf"; file-delete "/etc/resolv.conf"; file-create "/etc/resolv.conf", %(content => "nameserver 127.0.0.1"); bash "chattr +i /etc/resolv.conf";
This will remove the "immutable" attribute from
/etc/resolv.conf if it’s set.
Next it will remove the current
/etc/resolv.conf and write out a new one which
only refers to the local machine as DNS resolver. This is to ensure an existing
/etc/resolv.conf gets recreated with the configuration we want. Finally, it
adds back the immutable attribute to the file, so other processes won’t
To run the
sparrowfile and get the setup you desire, run the
--local_mode and wait.
If you want to run this on a remote machine to configure that one instead, you
You can check whether it actually worked by inspecting the files in
/etc/dnsmasq.d and your
/etc/resolv.conf. The easiest way to check their
contents would be by using
cat /etc/dnsmasq.d/dnsmasq.conf cat /etc/dnsmasq.d/resolv.conf cat /etc/resolv.conf
You should now have a working local DNS setup, configured programmatically through Sparrowdo. This allows you easily get it working on other machines as well, and updates can be done in a much simpler fashion for all of them together.
If you have more interest in automating configuration with Sparrowdo, go check their website, https://sparrowdo.wordpress.com/.