Fabric is a Python library and command-line tool for automating system administration tasks over SSH. It allows users to define Python functions for common operations and execute them remotely on multiple servers. Fabric has APIs for executing commands via SSH, uploading/downloading files, and abstracting servers into roles for easy management. It provides a Pythonic interface for deployment and administration of remote systems.

1. Fabric
Lo (Eric Lo)
http://lxneng.com
lxneng@gmail.com
twitter: @lxneng
Sunday, August 29, 2010

2. About
Fabric is a Python library and command-
line tool for streamlining the use of SSH
for application deployment or systems
administration tasks
capistrano in python
单 学 经
统
Sunday, August 29, 2010

3. Fabric is two things
Api for streamlining the use of ssh for
app development or system management
tasks
Command-line interface for calling
python methods
Sunday, August 29, 2010

4. Install
sudo easy_install fabric
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5. Example
vim fabfile.py
#!/usr/bin/env python
from fabric.api import env, run
env.hosts = ['xxx.com']
env.user = 'eric'
def du():
run("du -sh /home/eric")
Erics-MacBook:~ eric$ fab du
[xxx.com] run: du -sh /home/eric
[xxx.com] out: 942M
/home/eric
Done.
Disconnecting from xxx.com... done.
Sunday, August 29, 2010

6. Deploy my rails app
Erics-MacBook:~ eric$ cd NetBeans_Workspace/lxneng
Erics-MacBook:lxneng eric$ touch fabfile.py
Erics-MacBook:lxneng eric$ vim fabfile.py
#!/usr/bin/env python
# encoding: utf-8
from fabric.api import env, run, cd, local, put
env.hosts = ['192.168.1.5']
env.user = 'eric'
DEPLOY_PATH = '/var/www/'
APP_NAME = 'lxneng'
APP_PATH = '%s%s'%(DEPLOY_PATH, APP_NAME)
DATABASE_CONF_PATH = '/srv/conf/database.yml'
Sunday, August 29, 2010

7. pack & upload
def pack_code():
local('tar czf /tmp/%s.tgz .'%APP_NAME)
def upload_code():
put('/tmp/%s.tgz'%APP_NAME, '/tmp/')
with cd(APP_PATH):
run('tar xzf /tmp/%s.tgz'%APP_NAME)
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8. config & restart
def conf():
run("cp %s %s/config/"%(DATABASE_CONF_PATH, APP_PATH))
run("ln -nfs /srv/photos %s/public/photos"%APP_PATH)
with cd(APP_PATH):
run("rake db:migrate RAILS_ENV=production")
def restart():
run("touch %s/tmp/restart.txt"%APP_PATH)
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9. Deploy
def deploy():
pack_code()
upload_code()
conf()
restart()
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10. define roles
env.roledefs = {
‘testing’: [‘192.168.1.5’],
‘staging’: [‘.........’],
‘production’: [‘......’, ‘........’],
‘database’: [‘........’]
}
def testing():
env.hosts = env.roledefs[‘testing’]
env.user = ‘testuser’
# ...
def deploy():
# deploy code here
fab testing deploy
Sunday, August 29, 2010

11. Fabric Commands
• require: Make sure that certain environment variables
are available.
• prompt: Display a prompt to the user and store the input
in the given variable. Validation is optional.
• put: Upload files to the remote host(s).
• get: Download a file from a remote host.
• run: Run a shell command on the remote host(s).
• sudo: Run a root privileged shell command command on
the remote host(s).
• local: Run a command locally.
Sunday, August 29, 2010

12. Fabric Contrib Commands
• rsync_project: Synchronize a remote directory with the current project
directory via rsync.
• upload_project: Upload the current project to a remote system, tar-
gzipping during the move.
• exists: Return True if given path exists.
• first: Given one or more file paths, returns first one found, or None.
• upload_template: Render and upload a template text file to a remote host.
• sed: Run a search-and-replace on filename with given regex patterns.
• comment/uncomment: Attempt to (un)comment out all lines in filename
matching regex.
• contains: Return True if filename contains text.
• append: Append string (or list of strings) text to filename.
• confirm: Ask user a yes/no question and return their response as True /
False.
Sunday, August 29, 2010

13. Fabric Decorators
• hosts: Defines on which host or hosts to execute the wrapped
function.
• roles: Defines a list of role names, used to look up host lists.
• runs_once: Prevents wrapped function from running more than
once.
@hosts('user1@host1', 'host2', 'user2@host3')
@runs_once
def my_func():
pass
@roles('web')
def my_other_func():
pass
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14. app
fabfile
fabfile http://gist.github.com/472566
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15. Reference
Fabric documentation http://fabfile.org/
Pythonic Deployment with Fabric 0.9
Fabric: A Capistrano Alternative
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16. Q&A
Thank You
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