Can a Python Fabric task invoke other tasks and re

Question

I have a fabfile like the following:

@hosts('host1')
def host1_deploy():
    """Some logic that is specific to deploying to host1"""

@hosts('host2')
def host2_deploy():
    """Some logic that is specific to deploying to host2"""

def deploy():
    """"Deploy to both hosts, each using its own logic"""
    host1_deploy()
    host2_deploy()

I would like to do

fab deploy

and have it be equivalent to

fab host1_deploy host2_deploy

In other words, run each of the subtasks and for each one use the list of hosts that it specifies. However, this does not work. Instead, the deploy() task wants its own list of hosts that it will propogate to all of its subtasks.

Is there a way to update the deploy() task here so it will do what I want while leaving the subtasks alone so they can be run individually?

Answer 1

This is lame but it works as of Fabric 1.1.2

def host1_deploy():
    """Some logic that is specific to deploying to host1"""
    if env.host in ["host1"]:
        pass #this is only on host2

def host2_deploy():
    """Some logic that is specific to deploying to host2"""
    if env.host in ["host2"]:
        pass #this is only on host2

def deploy():
    """"Deploy to both hosts, each using its own logic"""
    host1_deploy()
    host2_deploy()

here's my test code:

@task
@roles(["prod_web","prod_workers"])
def test_multi():
    test_multi_a()
    test_multi_b()

def test_multi_a():
    if env.host in env.roledefs["prod_web"]:
        run('uname -a')

def test_multi_b():
    if env.host in env.roledefs["prod_workers"]:
        run('uname -a')

Answer 2

Since Fabric 1.3, the execute helper is now available to do just this. The documentation is available here: Intelligently executing tasks with execute.

Here is the example they use:

from fabric.api import run, roles

env.roledefs = {
    'db': ['db1', 'db2'],
    'web': ['web1', 'web2', 'web3'],
}

@roles('db')
def migrate():
    # Database stuff here.
    pass

@roles('web')
def update():
    # Code updates here.
   pass

And then to run both migrate and web from another task deploy:

def deploy():
    execute(migrate)
    execute(update)

And this will respect the roles and hosts lists that those tasks have.

Answer 3

Try this one. Obviously you want to replace local with run or sudo. The key is the empty @hosts decorator for deploy

from fabric.api import local
from fabric.decorators import hosts

@hosts('host1')
def host1_deploy():
    """Some logic that is specific to deploying to host1"""
    local('echo foo')

@hosts('host2')
def host2_deploy():
    """Some logic that is specific to deploying to host2"""
    local('echo bar')

@hosts('')
def deploy():
    """"Deploy to both hosts, each using its own logic"""
    host1_deploy()
    host2_deploy()

Answer 4

There's probably a better way to handle it, but you could pass both hosts to deploy(), and then in host1_deploy() and host2_deploy() check env.host:

def host1_deploy():
    if env.host in ['host1']:
         run(whatever1)

def host2_deploy():
    if env.host in ['host2']:
         run(whatever2)

@hosts('host1','host2')
def deploy():
    host1_deploy()
    host2_deploy()