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ansible/network/haproxy.py
Ravi Bhure 44b2cdb5f2 used ansible conventions to use trigered action ==> state, 
now only two states are available enabled/disabled_
get weight for backend server, is default behavior for both state,
supports set weight while enable server in lb pool
2014-12-05 11:44:43 -07:00

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Python
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#!/usr/bin/python
# -*- coding: utf-8 -*-
# (c) 2014, Ravi Bhure <ravibhure@gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible. If not, see <http://www.gnu.org/licenses/>.
DOCUMENTATION = '''
---
module: haproxy
short_description: An Ansible module to handle states enable/disable server and set weight to backend host in haproxy using socket commands.
description:
- The Enable Haproxy Backend Server, with
supports get current weight for server (default) and
set weight for haproxy backend server when provides.
- The Disable Haproxy Backend Server, with
supports get current weight for server (default) and
shutdown sessions while disabling backend host server.
notes:
- "enable or disable commands are restricted and can only be issued on sockets configured for level 'admin', "
- "Check - http://haproxy.1wt.eu/download/1.5/doc/configuration.txt, "
- "Example: 'stats socket /var/run/haproxy.sock level admin'"
options:
state:
description:
- describe the desired state of the given host in lb pool.
required: true
default: null
choices: [ "enabled", "disabled" ]
host:
description:
- Host (backend) to operate in Haproxy.
required: true
default: null
socket:
description:
- Haproxy socket file name with path.
required: false
default: /var/run/haproxy.sock
backend:
description:
- Name of the haproxy backend pool.
Required, else auto-detection applied.
required: false
default: auto-detected
weight:
description:
- The value passed in argument. If the value ends with the '%' sign, then the new weight will be relative to the initially cnfigured weight. Relative weights are only permitted between 0 and 100% and absolute weights are permitted between 0 and 256.
required: false
default: null
shutdown_sessions:
description:
- When disabling server, immediately terminate all the sessions attached to the specified server. This can be used to terminate long-running sessions after a server is put into maintenance mode, for instance.
required: false
default: false
'''
EXAMPLES = '''
examples:
# disable server in 'www' backend pool
- haproxy: state=disabled host={{ inventory_hostname }} backend=www
# disable server without backend pool name (apply to all available backend pool)
- haproxy: state=disabled host={{ inventory_hostname }}
# disable server, provide socket file
- haproxy: state=disabled host={{ inventory_hostname }} socket=/var/run/haproxy.sock backend=www
# disable backend server in 'www' backend pool and drop open sessions to it
- haproxy: state=disabled host={{ inventory_hostname }} backend=www socket=/var/run/haproxy.sock shutdown_sessions=true
# enable server in 'www' backend pool
- haproxy: state=enabled host={{ inventory_hostname }} backend=www
# enable server in 'www' backend pool with change server(s) weight
- haproxy: state=enabled host={{ inventory_hostname }} socket=/var/run/haproxy.sock weight=10 backend=www
author: Ravi Bhure <ravibhure@gmail.com>
version_added: "1.9"
'''
import logging
import socket
import re
logger = logging.getLogger(__name__)
DEFAULT_SOCKET_LOCATION="/var/run/haproxy.sock"
RECV_SIZE = 1024
def main():
ACTION_CHOICES = [
'enabled',
'disabled',
]
# load ansible module object
module = AnsibleModule(
argument_spec = dict(
state = dict(required=True, default=None, choices=ACTION_CHOICES),
host=dict(required=True, default=None),
backend=dict(required=False, default=None),
weight=dict(required=False, default=None),
socket = dict(required=False, default=DEFAULT_SOCKET_LOCATION),
shutdown_sessions=dict(required=False, default=False),
),
supports_check_mode=True,
)
state = module.params['state']
host = module.params['host']
backend = module.params['backend']
weight = module.params['weight']
socket = module.params['socket']
shutdown_sessions = module.params['shutdown_sessions']
##################################################################
# Required args per state:
# (enabled/disabled) = (host)
#
# AnsibleModule will verify most stuff, we need to verify
# 'socket' manually.
##################################################################
##################################################################
if not socket:
module.fail_json('unable to locate haproxy.sock')
##################################################################
required_one_of=[['state', 'host']]
ansible_haproxy = HAProxy(module, **module.params)
if module.check_mode:
module.exit_json(changed=True)
else:
ansible_haproxy.act()
##################################################################
######################################################################
class TimeoutException(Exception):
pass
class HAProxy(object):
"""
Used for communicating with HAProxy through its local UNIX socket interface.
Perform common tasks in Haproxy related to enable server and
disable server.
The complete set of external commands Haproxy handles is documented
on their website:
http://haproxy.1wt.eu/download/1.5/doc/configuration.txt#Unix Socket commands
"""
def __init__(self, module, **kwargs):
self.module = module
self.state = kwargs['state']
self.host = kwargs['host']
self.backend = kwargs['backend']
self.weight = kwargs['weight']
self.socket = kwargs['socket']
self.shutdown_sessions = kwargs['shutdown_sessions']
self.command_results = []
def execute(self, cmd, timeout=200):
"""
Executes a HAProxy command by sending a message to a HAProxy's local
UNIX socket and waiting up to 'timeout' milliseconds for the response.
"""
buffer = ""
self.client = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
self.client.connect(self.socket)
self.client.sendall('%s\n' % cmd)
result = ''
buf = ''
buf = self.client.recv(RECV_SIZE)
while buf:
result += buf
buf = self.client.recv(RECV_SIZE)
self.command_results = result.strip()
self.client.close()
return result
def enabled(self, host, backend, weight):
"""
Enables backend server for a particular backend.
enable server <backend>/<server>
If the server was previously marked as DOWN for maintenance, this marks the
server UP and checks are re-enabled.
Both the backend and the server may be specified either by their name or by
their numeric ID, prefixed with a sharp ('#').
This command is restricted and can only be issued on sockets configured for
level "admin".
Syntax: enable server <pxname>/<svname>
"""
svname = host
if self.backend is None:
output = self.execute('show stat')
#sanitize and make a list of lines
output = output.lstrip('# ').strip()
output = output.split('\n')
result = output
for line in result:
if 'BACKEND' in line:
result = line.split(',')[0]
pxname = result
cmd = "get weight %s/%s ; enable server %s/%s" % (pxname, svname, pxname, svname)
if weight:
cmd += "; set weight %s/%s %s" % (pxname, svname, weight)
self.execute(cmd)
else:
pxname = backend
cmd = "get weight %s/%s ; enable server %s/%s" % (pxname, svname, pxname, svname)
if weight:
cmd += "; set weight %s/%s %s" % (pxname, svname, weight)
self.execute(cmd)
def disabled(self, host, backend, shutdown_sessions):
"""
Disable backend server for a particular backend.
disable server <backend>/<server>
Mark the server DOWN for maintenance. In this mode, no more checks will be
performed on the server until it leaves maintenance.
If the server is tracked by other servers, those servers will be set to DOWN
during the maintenance.
In the statistics page, a server DOWN for maintenance will appear with a
"MAINT" status, its tracking servers with the "MAINT(via)" one.
Both the backend and the server may be specified either by their name or by
their numeric ID, prefixed with a sharp ('#').
This command is restricted and can only be issued on sockets configured for
level "admin".
Syntax: disable server <pxname>/<svname>
"""
svname = host
if self.backend is None:
output = self.execute('show stat')
#sanitize and make a list of lines
output = output.lstrip('# ').strip()
output = output.split('\n')
result = output
for line in result:
if 'BACKEND' in line:
result = line.split(',')[0]
pxname = result
cmd = "get weight %s/%s ; disable server %s/%s" % (pxname, svname, pxname, svname)
if shutdown_sessions == 'true':
cmd += "; shutdown sessions server %s/%s" % (pxname, svname)
self.execute(cmd)
else:
pxname = backend
cmd = "get weight %s/%s ; disable server %s/%s" % (pxname, svname, pxname, svname)
if shutdown_sessions == 'true':
cmd += "; shutdown sessions server %s/%s" % (pxname, svname)
self.execute(cmd)
def act(self):
"""
Figure out what you want to do from ansible, and then do the
needful (at the earliest).
"""
# toggle enable/disbale server
if self.state == 'enabled':
self.enabled(self.host, self.backend, self.weight)
elif self.state == 'disabled':
self.disabled(self.host, self.backend, self.shutdown_sessions)
else:
self.module.fail_json(msg="unknown state specified: '%s'" % \
self.state)
self.module.exit_json(stdout=self.command_results, changed=True)
# import module snippets
from ansible.module_utils.basic import *
main()
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