Awesome
šØāš Welder
Welder allows you to set up a Linux server with plain shell scripts.
I wrote it out of frustration with Ansible. Ansible is an amazing and powerful tool, but for my needs it's just too much. 90% of the time all I need is to be able to run a shell script on the server, without extra dependencies.
In most basic terms, that's what welder does.
But there's some more.
ā ļø NOTE: if you're looking for the previous version of welder, you'll find it here.
Features
- set up your server with a single command (
welder run <playbook> <server>
) - run a set of organized reusable shell scripts
- use simple template syntax (
{{ VAR_NAME }}
) to substitute config variables
Directory structure
An example directory structure:
āāā playbook.conf
āāā config.conf
āāā firewall
āĀ Ā āāā files
āĀ Ā āĀ Ā āāā rules.v4
āĀ Ā āāā firewall.sh
āāā nginx
āĀ Ā āāā nginx.sh
āāā system
āĀ Ā āāā files
āĀ Ā āĀ Ā āāā 10periodic
āĀ Ā āĀ Ā āāā 50unattended-upgrades
āĀ Ā āĀ Ā āāā ssh_key
āĀ Ā āāā system.sh
āāā website
āāā files
āĀ Ā āāā site.conf.template
āāā website.sh
Playbook
Playbook is just a list of modules to execute. Example:
# playbook.conf
system
firewall
nginx
website
Config
Config file:
SITE_DOMAIN = "example.com"
SITE_DIR = "/var/www"
You can reference config variables in your scripts like this:
#!/bin/sh
set -xeu
. ./config.conf
echo $SITE_DOMAIN
Templates
Welder offers simple sed
-based templates that interpolate variables in double brackets
with values defined in config.
# website/files/nginx-site.conf.template
server {
listen 80;
server_name {{ SITE_DOMAIN }};
root {{ SITE_DIR }}/current/public;
}
Usage
Run the playbook with the following command:
welder run playbook.conf user@example.com
How it works
Welder goes through the modules defined in playbook.conf
, copies them to a
cache directory, compiles config files and templates, rsync
s the directory to
the server. Then it runs the setup
script that invokes all *.sh
files
within the playbook (all scripts will be called with sudo
).
Example setup script
# nginx/nginx.sh
# NOTE: sudo isn't necessary because the whole script will be
# invoked as `sudo nginx/nginx.sh`
set -xeu # 'u' will give you warnings on unbound config variables
add-apt-repository -y ppa:nginx/stable
sapt-get update && apt-get install -y nginx
service nginx start
cp files/nginx.conf /etc/nginx/nginx.conf
# Disable default site
if [ -f /etc/nginx/sites-enabled/default ]; then
rm /etc/nginx/sites-enabled/default
fi
service nginx restart
Installation
The only dependency required by welder is rsync
(which should be
pre-installed on your system in most cases).
-
Check out welder into
~/.welder
(or whatever location you prefer):$ git clone https://github.com/pch/welder.git ~/.welder
-
Add
~/.welder/bin
to your$PATH
for access to thewelder
command-line utility.$ echo 'export PATH="$PATH:$HOME/.welder/bin"' >> ~/.bash_profile
Ubuntu Desktop note: Modify your
~/.bashrc
instead of~/.bash_profile
.Zsh note: Modify your
~/.zshrc
file instead of~/.bash_profile
. -
Restart your shell so that PATH changes take effect. (Opening a new terminal tab will usually do it.) Now check if welder was set up:
$ which welder /Users/my-user/Code/welder/bin/welder
Caveats
Since welder allows you to run anything on the server, you should use it
with caution. It won't protect you from screw-ups, like
rm -rf "/$undefined_variable"
.
Use at your own risk.
Alternatives
There's an alternative version of welder (the classic version), re-implemented in Python by @thomas-mc-work.