Fabric学習のまとめ

Fabricノート

何ができる？

インストール

from fabric.api import run

def host_type():
    run('uname -s')

コマンドラインツールfabの使用

コンテキストマネージャ

from fabric.api import settings, run

def exists(path):
    with settings(warn_only=True):
        return run('test -e %s' % path)

一時指定user

from fabric.api import env, run

env.user = 'implicit_user'
env.hosts = ['host1', 'explicit_user@host2', 'host3']

def print_user():
    with hide('running'):
        run('echo "%(user)s"' % env)

fabricの実行ポリシー

fabのオプションとパラメータ

fab --help

Usage: fab [options] [:arg1,arg2=val2,host=foo,hosts='h1;h2',...] ...

Options:
  -h, --help            show this help message and exit
  -d NAME, --display=NAME
                        print detailed info about command NAME
  -F FORMAT, --list-format=FORMAT
                        formats --list, choices: short, normal, nested
  -I, --initial-password-prompt
                        Force password prompt up-front
  -l, --list            print list of possible commands and exit
  --set=KEY=VALUE,...   comma separated KEY=VALUE pairs to set Fab env vars
  --shortlist           alias for -F short --list
  -V, --version         show program's version number and exit
  -a, --no_agent        don't use the running SSH agent
  -A, --forward-agent   forward local agent to remote end
  --abort-on-prompts    abort instead of prompting (for password, host, etc)
  -c PATH, --config=PATH
                        specify location of config file to use
  --colorize-errors     Color error output
  -D, --disable-known-hosts
                        do not load user known_hosts file
  -e, --eagerly-disconnect
                        disconnect from hosts as soon as possible
  -f PATH, --fabfile=PATH
                        python module file to import, e.g. '../other.py'
  -g HOST, --gateway=HOST
                        gateway host to connect through
  --gss-auth            Use GSS-API authentication
  --gss-deleg           Delegate GSS-API client credentials or not
  --gss-kex             Perform GSS-API Key Exchange and user authentication
  --hide=LEVELS         comma-separated list of output levels to hide
  -H HOSTS, --hosts=HOSTS
                        comma-separated list of hosts to operate on
  -i PATH               path to SSH private key file. May be repeated.
  -k, --no-keys         don't load private key files from ~/.ssh/
  --keepalive=N         enables a keepalive every N seconds
  --linewise            print line-by-line instead of byte-by-byte
  -n M, --connection-attempts=M
                        make M attempts to connect before giving up
  --no-pty              do not use pseudo-terminal in run/sudo
  -p PASSWORD, --password=PASSWORD
                        password for use with authentication and/or sudo
  -P, --parallel        default to parallel execution method
  --port=PORT           SSH connection port
  -r, --reject-unknown-hosts
                        reject unknown hosts
  --system-known-hosts=SYSTEM_KNOWN_HOSTS
                        load system known_hosts file before reading user
                        known_hosts
  -R ROLES, --roles=ROLES
                        comma-separated list of roles to operate on
  -s SHELL, --shell=SHELL
                        specify a new shell, defaults to '/bin/bash -l -c'
  --show=LEVELS         comma-separated list of output levels to show
  --skip-bad-hosts      skip over hosts that can't be reached
  --skip-unknown-tasks  skip over unknown tasks
  --ssh-config-path=PATH
                        Path to SSH config file
  -t N, --timeout=N     set connection timeout to N seconds
  -T N, --command-timeout=N
                        set remote command timeout to N seconds
  -u USER, --user=USER  username to use when connecting to remote hosts
  -w, --warn-only       warn, instead of abort, when commands fail
  -x HOSTS, --exclude-hosts=HOSTS
                        comma-separated list of hosts to exclude
  -z INT, --pool-size=INT
                        number of concurrent processes to use in parallel mode

並列実行

from fabric.api import *

def update():
    with cd("/srv/django/myapp"):
        run("git pull")

def reload():
    sudo("service apache2 reload")

1.update on web1
2.update on web2
3.update on web3
4.reload on web1
5.reload on web2
6.reload on web3

1.update on web1, web2, and web3
2.reload on web1, web2, and web3

from fabric.api import *


@parallel
def runs_in_parallel():
    pass

def runs_serially():
    pass

1. runs_in_parallel on host1, host2, and host3
2. runs_serially on host1
3. runs_serially on host2
4. runs_serially on host3

from fabric.api import *

def runs_in_parallel():
    pass

@serial
def runs_serially():
    pass

from fabric.api import *

@parallel(pool_size=5)
def heavy_task():
    # lots of heavy local lifting or lots of IO here

$ fab -P -z 5 heavy_task

タスク@taskアクセラレータの定義

from fabric.api import task

@task(alias='dwm')
def deploy_with_migrations():
    pass

$ fab --list
Available commands:

    deploy_with_migrations
    dwm

class MyTask(Task):
    name = "deploy"
    def run(self, environment, domain="whatever.com"):
        run("git clone foo")
        sudo("service apache2 restart")

instance = MyTask()

@task
def deploy(environment, domain="whatever.com"):
    run("git clone foo")
    sudo("service apache2 restart")

from fabric.api import task
from fabric.tasks import Task

class CustomTask(Task):
    def __init__(self, func, myarg, *args, **kwargs):
        super(CustomTask, self).__init__(*args, **kwargs)
        self.func = func
        self.myarg = myarg

    def run(self, *args, **kwargs):
        return self.func(*args, **kwargs)

@task(task_class=CustomTask, myarg='value', alias='at')
def actual_task():
    pass


task_obj = CustomTask(actual_task, myarg='value')

ネーミングスペース

fabfile
├── __init__.py

from fabric.api import task

@task
def deploy():
    pass

@task
def compress():
    pass

$ fab --list
Available commands:

    compress
    deploy

from fabric.api import task
@task
def add_backend():
    pass

deploy
compress
lb.add_backend

.
├── __init__.py
├── db
│   ├── __init__.py
│   └── migrations.py
└── lb.py

@task
def hidden_task():
    pass

Available commands:

    compress
    deploy
    lb.add_backend
    lb.hidden_task

Available commands (remember to call as module.[...].task):

    compress
    deploy
    lb:
        add_backend

終端テキストの色

fabric.colors.blue(text, bold=False)
fabric.colors.cyan(text, bold=False)
fabric.colors.green(text, bold=False)
fabric.colors.magenta(text, bold=False)
fabric.colors.red(text, bold=False)
fabric.colors.white(text, bold=False)
fabric.colors.yellow(text, bold=False)

from fabric.colors import red, green, _wrap_with

#         text
print _wrap_with('30')("i am black")

コンテキストマネージャ

デコレーション

ネットワーク関連の部分

一般的な操作

# Simplest form:
environment = prompt('Please specify target environment: ')

# With default, and storing as env.dish:
prompt('Specify favorite dish: ', 'dish', default='spam & eggs')

# With validation, i.e. requiring integer input:
prompt('Please specify process nice level: ', key='nice', validate=int)

# With validation against a regular expression:
release = prompt('Please supply a release name',
        validate=r'^\w+-\d+(\.\d+)?$')

# Prompt regardless of the global abort-on-prompts setting:
with settings(abort_on_prompts=False):
    prompt('I seriously need an answer on this! ')