Tissu for Fabric¶

About¶

Fabric is an incredible tool to automate deployement of application or administration of remote machines. As Fabric’s function are rather low-level, you’ll probably quickly see a need for managing different environnements like production, staging...

Tissu give you the hability to define your environement (the remote machines) and the role of each machine.

Tissu’s features are:

a simple convention
settings à la Django
settings with python file

Contents:

Installation¶

Tissu is on pypi.

Setuptools¶

easy_install -U tissu

PIP¶

We are not stabe for the moment, so you need the extra argument –pre

pip install --pre tissu

Source code¶
Get the source from Tissu’s GitHub
run python setup.py install.

Quickstart¶

Use the role mechanism of tissu in your fabfile.py¶

First, you need to install tissu...

So create your fabfile.py with these lines of code.

import os, sys

current_dir = os.path.dirname(os.path.abspath(__file__))
sys.path.append(current_dir)

from fabric.api import *
from tissu.tasks import *

We need to add the current directory to sys.path. Without these lines the environnement loader can’t load any settings.

Now you have 3 tasks, e and tissu_init.

$ fab -l
Available commands:

    e               Environnement loader
    tissu_init      Init the settings scaffolding
    tissu_print     Print FABRIC env dict and TISSU settings public properties

Now you have to generate the default settings scaffolding. That’s the purpose of tissu_init. By default, Tissu need a python module “settings.default”.

Now, launch the taks tissu_ini

$ fab tissu_init
[localhost] local: mkdir -p settings
[localhost] local: touch settings/__init__.py
settings/default.py written

Done.

Now tissu had everithing he need for handle your first environment.

.
├── fabfile.py
└── settings
    ├── default.py
    └── __init__.py

Create a new file in settings foo.py, with this sample of code.

# My first environnement

SERVER_A = {
 "user" : "foo",
 "hostname" : "localhost",
 "password": "password",
}

SERVER_B = {
 "user" : "foo",
 "hostname" : "server.example.org",
 "key": "/home/foo/.ssh/id_rsa.pub"

}

FABRIC_ROLES = {
    "db":       [SERVER_A],
    "web":      [SERVER_B],
}

We can load our first environnement

fab e:foo
Environment foo sucessfully loaded :)

Done.

We will add some tasks in order to do something with this environement.

def hello():
    run("echo hello && uptime")

@roles("db")
@task
def hello_db():
    hello()

@roles("web")
@task
def hello_web():
    hello()

@roles("all")
@task
def hello_all():
    hello()

Now you have three new tasks :

hello_db will execute hello to the SERVER_A, because it is in the role db.

hello_web will execute hello to the SERVER_B, because it is in the role web.

hello_all will execute hello in all remote machines.

Note: The role all is automaticly generate by tissu. Note: You have to setup the foo settings with real remote machines.

A example of what you get when you try these tasks :

$ fab e:foo hello_db hello_web hello_all
Environment foo sucessfully loaded :)
[thierry@localhost:22] Executing task 'hello_db'
[thierry@localhost:22] run: echo hello && uptime
[thierry@localhost:22] out: hello
[thierry@localhost:22] out:  16:17:57 up 13 days,  6:02,  5 users,  load average: 0,16, 0,31, 0,38
[thierry@localhost:22] out:

[thierry@192.168.0.19:22] Executing task 'hello_web'
[thierry@192.168.0.19:22] run: echo hello && uptime
[thierry@192.168.0.19:22] out: hello
[thierry@192.168.0.19:22] out:  16:18:00 up 13 days,  6:02,  5 users,  load average: 0,23, 0,32, 0,38
[thierry@192.168.0.19:22] out:

[thierry@192.168.0.19:22] Executing task 'hello_all'
[thierry@192.168.0.19:22] run: echo hello && uptime
[thierry@192.168.0.19:22] out: hello
[thierry@192.168.0.19:22] out:  16:18:00 up 13 days,  6:02,  5 users,  load average: 0,23, 0,32, 0,38
[thierry@192.168.0.19:22] out:

[thierry@localhost:22] Executing task 'hello_all'
[thierry@localhost:22] run: echo hello && uptime
[thierry@localhost:22] out: hello
[thierry@localhost:22] out:  16:18:00 up 13 days,  6:02,  5 users,  load average: 0,23, 0,32, 0,38
[thierry@localhost:22] out:

Retrieve the settings loaded by tissu¶

We assume that you have a foo.py settings created.

First we add a new settings : BAR, our foo settings become :

::

# My first environnement

SERVER_A = {: “user” : “thierry”, “hostname” : “localhost”, “password”: “cordonchat”,

}

SERVER_B = {: “user” : “thierry”, “hostname” : “192.168.0.19”, “password”: “cordonchat”

}

FABRIC_ROLES = {: “db”: [SERVER_A], “web”: [SERVER_B],

}

BAR = “foo”

In our fabfile, we add a new task that print us the value of BAR.

@task
def bar():
    from tissu.conf import settings
    puts("BAR value is: %s" % getattr(settings, "BAR", "not found !"))

When we don’t specify any environnement we’ve got :

$ fab bar
BAR value is: ERROR !

Done.

And when we use our foo environement we’ve got :

$ fab e:foo bar
Environment foo sucessfully loaded :)
BAR value is: foo

Done.

Additionnaly, Tissu add the settings into the fabric env.

@task
def envbar():
    from fabric.api import env
    puts("BAR value from env is: %s " % getattr(env.my_settings, "BAR", "not found !"))

And then we got :

$ fab e:foo envbar
Environment foo sucessfully loaded :)
BAR value from env is: foo

Done.