smash

Smart Meta Automation Shell

philosophy

smash is a shell scripting extension which simplifies writing scripts which can run on multiple hosts. It also provides very intuitive shortcuts for most common deployment scenarios. smash uses python fabric behind the scene to achieve these goals.

requirements

To use smash you need python. In addition you need the following python libraries:

1. fabric
2. jinja2
3. optparse

usage

Currently, you need three folders to organize your files. This will change in future to allow more flexibility.

1. config - Here you will have the global configuration which can be used in the scripts
2. templates - You can keep the template files here. e.g. Templated version of mysql.conf or mongodb.conf or similar.
3. recipes - you keep your shell command recipes here

Use the following syntax to run your smash scripts.

# runs the recipe install_pkgs in recipe/ubuntu.sh with remote hosts `web1`, `web2`, `web3`
# it uses the configuration file from from config/ubuntu.py
python smash.py -c ubuntu ubuntu.install_pkgs -H web1 web2 web3

syntax

Every shell commmand used in smash recipes have a prefix. This section describes the various prefix used to modulate the shell command.

prefix @d

This prefix defines a variable in smash. The variable is available for local as well remote commands.

@d domain www.clozr.com

prefix !

This prefix instructs to run a shell command <cmd> on local host.

! <cmd>

If you prefix all command wih !, resulting script will be a valid shell script. But the real power of this prefix is that it accepts templated command. Following example illustrates this by creating a certificate signing request:

! mkdir -p ssl/{{domain}}
! cd ssl/{{domain}} && openssl req -newkey rsa:2048 -nodes -keyout {{domain}}.key -out {{domain}}.csr -subj "/C={{country}}/ST={{state}}/L={{city}}/O={{company}}/OU=IT/CN={{domain}}"

You can use this recipe with following configuration

ssl_cert = {
'country': 'US',
'state' : 'CA',
'city': 'Mountain View',
'company': 'Clozr Inc',
'domain' : 'www.clozr.com',
}

prefix -

This prefix instructs to run a shell command <cmd> on all specified remote hosts:

- <cmd>

prefix +

This prefix instructs to run a shell command <cmd> on all specified remote hosts in sudo mode:

+ <cmd>  # run the command on host web1, web2, web3 in sudo mode

Following example adds mongodb and node.js repository on ubuntu on all connected hosts.

  + apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
  + echo "deb http://repo.mongodb.org/apt/ubuntu "$(lsb_release -sc)"/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list
  + apt-add-repository ppa:chris-lea/node.js
  + apt-get update