python-fleet

A python client for fleet

Full documentation available at python-fleet.readthedocs.org. Source for the documentation is in fleet/v1/docs/

Install

Install from PyPI

$ pip install fleet

Install from source

$ git clone https://github.com/cnelson/python-fleet
$ cd python-fleet && python setup.py install

Quick Start

This is a high-level overview of python-fleet's interface. For full documentation on all methods, see the documentation for individual classes.

Importing fleet

Always import the specific version you wish to use. Currently 'v1' is supported.

import fleet.v1 as fleet

Error handling

All methods except for the constructor can raise an APIError if fleet responds with an error.

Developers must catch and handle these exceptions. Do not ignore errors.

Create a client

The fleet API documentation states that clients should generate their bindings using the discovery document fleet provides.

python-fleet will attempt to retrieve and parse this document when it is instantiated. Should any error occur during this process ValueError will be raised.

python-fleet supports connecting through SSH tunnels. See the full Client documentation for additional information on configuring SSH tunnels.

from __future__ import print_function

# connect to fleet over tcp
try:
    fleet_client = fleet.Client('http://127.0.0.1:49153')
except ValueError as exc:
    print('Unable to discover fleet: {0}'.format(exc))
    raise SystemExit

# or via an ssh tunnel
try:
    fleet_client = fleet.Client('http://127.0.0.1:49153', ssh_tunnel='198.51.100.23')
except ValueError as exc:
    print('Unable to discover fleet: {0}'.format(exc))
    raise SystemExit

# or over a unix domain socket
try:
    fleet_client = fleet.Client('http+unix://%2Fvar%2Frun%2Ffleet.sock')
except ValueError as exc:
    print('Unable to discover fleet: {0}'.format(exc))
    raise SystemExit

Create a unit

Fleet units can be created in several different ways. See the Unit documenation for full explanations of each option

Instantiate and manually add options

unit = fleet.Unit()
unit.add_option('Service', 'ExecStart', '/usr/bin/sleep 1d')

From an existing list of options

unit = fleet.Unit(options=[{'section': 'Service', 'name': 'ExecStart', 'value': '/usr/bin/sleep 1d'}])

From a string containing a unit file

unit = fleet.Unit(from_string="[Service]\nExecStart=/usr/bin/sleep1d")

From a file

unit = fleet.Unit(from_file='/path/to/foo.service')

Once the unit object has been created, pass it to the create_unit method to submit the unit to the fleet cluster

try:
    unit = fleet_client.create_unit('foo.service', unit)
except fleet.APIError as exc:
    print('Unable to create unit: {0}'.format(exc))
    raise SystemExit

Modify a Unit's desiredState

Once a unit has been submited to the cluster, the only writable field is desiredState.

To update a unit's desired state call the set_desired_state method.

try:
    unit.set_desired_state('inactive')
except fleet.APIError as exc:
    print('Unable to modify unit: {0}'.format(exc))
    raise SystemExit

List Units

Returns a generator that yields each Unit in the cluster

try:
    for unit in fleet.list_units():
        print(unit)
except fleet.APIError as exc:
    print('Unable to list units: {0}'.format(exc))
    raise SystemExit

Get a Unit

Retreive a specific Unit from the cluster by name.

If the unit is not found, APIError will be raised with code == 404

try:
    unit = fleet.get_unit('foo.service')
except fleet.APIError as exc:
    if exc.code == 404:
        print('Unit foo.service does not exist.')
    else:
        print('Unable to get unit: {0}'.format(exc))

List Current Unit State

Returns a generator tht yields the current UnitState for each unit in the cluster

See the fleet API documention's section on UnitState for information on the difference between Unit and UnitState

try:
    for unit_state in fleet.list_unit_states():
        print(unit_state)
except fleet.APIError as exc:
    print('Unable to list unit state: {0}'.format(exc))
    raise SystemExit

List Machines

Return a generator that yields each Machine in the cluster

try:
    for machine in fleet.list_machines():
        print(machine)
except fleet.APIError as exc:
    print('Unable to list machines: {0}'.format(exc))
    raise SystemExit