chopsticks 0.1

Chopsticks is an orchestration library: it lets you manage and configure remote hosts over SSH.

Naturally this is agentless and nothing needs to be installed on the remote host.

It’s perhaps best compared to Ansible or Fabric, but has some clever transport magic which means it’s very easy to develop with: you just write Python functions that can be called from the orchestration host. No invoking bash commands (eg. Fabric) or writing self-contained scripts with constrained input and output formats (eg. Ansible).

Example

With chopsticks you can simply import functions and hand them to the remote host to be executed.

First stand up an SSH Tunnel:

from chopsticks.tunnel import Tunnel
tun = Tunnel('troy')

Then you can pass a function, to be called on the remote host:

import time
print('Time on %s:' % t.host, t.call(time.time))

The intention would be to build in some useful facts and config management capabilities; currently only chopsticks.facts.ip is a thing:

from chopsticks.facts import ip

print('%s ip:' % t.host, t.call(ip))

API

class Tunnel(host, user=None)

Construct an SSH Tunnel to connect to the given host. If user is given, connect as this user; otherwise connect as the default user (from SSH configs or the currently logged in user).

tunnel.call(callable, *args, **kwargs)

Call the given callable on the remote host with the given arguments.

Any pickleable function can be called with any pickleable arguments. However, the function must return a value that is JSON-serializable. This constraint arises for security reasons, to ensure that any highjacking of the remote process cannot be used to compromise the controller machine.

How it works

The SSH tunnel invokes the python binary on the remote host, and feeds it a bootstrap script via stdin.

Once bootstrapped, the remote “agent” sets up bi-directional communication over the stdin/stdout of the tunnel (stderr is currently not consumed and can therefore be used to feed debugging information back to the controlling terminal). This communication is used (currently) for two purposes:

• An RPC system to invoke arbitrary callables within the remote agent and pass the returned values back to the controller.

• A PEP-302 import hook system, allowing the remote agent to import pure-Python code from the controller (NB. the controller can only serve Python modules that live within the filesystem - import hooks such as zipimport/compressed eggs are not currently supported).

stdin/stdout on the agent are redirected to /dev/null.

License

Apache License 2.0