Can a Python Fabric task invoke other tasks and respect their hosts lists?

Question

I have a fabfile like the following:

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

@hosts(\'host2\         


        

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

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 3

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()

Answer 4

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, execute

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.