django fabric set hosts for deployment

Question

I want to deploy my code in localhost and my live version for this automation i used fabric. My basic fabric file look like:

 def localhost():
    "Use the local virtual server"
    env.hosts = ['127.0.0.1']
    env.user = 'user'
    env.path = '/var/www/html/{}'.format(env['project_name'])
    env.virtualhost_path = env.path

def webserver():
    "Use the actual webserver"
    env.hosts = ['www.example.com']
    env.user = 'username'
    env.path = '/var/www/html/{}'.format(env['project_name'])
    env.virtualhost_path = env.path

def setup():
require('hosts', provided_by=[localhost])
require('path')

sudo("apt-get update -y")
sudo("apt-get install git -y")
sudo("apt-get install postgresql libpq-dev python-dev python-pip -y")
sudo("apt-get install redis-server -y")
sudo("apt-get install nginx -y")

sudo('aptitude install -y python-setuptools')
sudo('apt-get install python-pip')
sudo('pip install virtualenv virtualenvwrapper')

For now i only want to deploy to my local machine. When I do this it gives me erro saying

The command 'setup' failed because the following required environment variable was not defined:
hosts

Try running the following command prior to this one, to fix the problem:
localhost

What does provided_by=([localhost]) do in here. I guess it should provide the information like hosts and user in localhost.

Why I am getting this error ?? Need help

Answer 1

I'm not sure why that doesn't work other than it's not mentioned in the docs as how host lists get constructed. Your options for setting the host value are:

1. Specify env.hosts = ['127.0.0.1'] globally in your fabfile
2. Pass the host to fab: fab -H 127.0.0.1 setup
3. Call the localhost task: fab localhost setup
4. Use the @hosts decorator on your setup function

See http://docs.fabfile.org/en/1.10/usage/execution.html#how-host-lists-are-constructed

Answer 2

fabric.operations.require(*keys, **kwargs):

Check for given keys in the shared environment dict and abort if not found... The optional keyword argument provided_by may be a list of functions or function names or a single function or function name which the user should be able to execute in order to set the key or keys; it will be included in the error output if requirements are not met.

http://docs.fabfile.org/en/1.10/api/core/operations.html?highlight=require#fabric.operations.require

That why you get the error message saying to run localhost first, then setup :

fab localhost setup