Fabric is a high level Python (2.7, 3.4+) library designed to execute shell commands remotely over SSH, yielding useful Python objects in return:

>>> from fabric import Connection
>>> result = Connection('web1.example.com').run('uname -s')
>>> msg = "Ran {.command!r} on {.host}, got this stdout:\n{.stdout}"
>>> print(msg.format(result))
Ran "uname -s" on web1.example.com, got this stdout:
Linux

It builds on top of Invoke (subprocess command execution and command-line features) and Paramiko (SSH protocol implementation), extending their APIs to complement one another and provide additional functionality.

Core use cases for Fabric include (but are not limited to):

• Single commands on individual hosts:

  >>> result = Connection('web1').run('hostname')
  web1
  >>> result
  <Result cmd='hostname' exited=0>
  

• Single commands across multiple hosts (via varying methodologies: serial, parallel, etc):

  >>> result = SerialGroup('web1', 'web2').run('hostname')
  web1
  web2
  >>> result
  {<Connection host=web1>: <Result cmd='whoami' exited=0>, ...}
  

• Python code blocks (functions/methods) targeted at individual connections:

  >>> def disk_free(c):
  >>> uname = c.run('uname -s', hide=True)
  >>> if 'Linux' in uname:
  ... command = "df -h / | tail -n1 | awk '{print 5ドル}'"
  ... return c.run(command, hide=True).stdout.strip()
  ... err = "No idea how to get disk space on {}!".format(uname)
  ... raise Exit(err)
  ...
  >>> disk_free(Connection('web1'))
  '33%'
  

• Python code blocks on multiple hosts:

  >>> def disk_free(c):
  ... # same as above!
  ...
  >>> {c: disk_free(c) for c in SerialGroup('web1', 'web2', 'db1')}
  {<Connection host=web1>: '33%', <Connection host=web2>: '17%', ...}
  

In addition to these library-oriented use cases, Fabric makes it easy to integrate with Invoke's command-line task functionality, invoking via a fab binary stub:

• Python functions, methods or entire objects can be used as CLI-addressable tasks, e.g. fab deploy;
• Tasks may indicate other tasks to be run before or after they themselves execute (pre- or post-tasks);
• Tasks are parameterized via regular GNU-style arguments, e.g. fab deploy --env=prod -d;
• Multiple tasks may be given in a single CLI session, e.g. fab build deploy;
• Much more - all other Invoke functionality is supported - see its documentation for details.

We've packaged modern Fabric in a manner that allows installation alongside Fabric 1, so you can upgrade at whatever pace your use case requires. There are multiple possible approaches -- see our detailed upgrade documentation for details.