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community.general/plugins/modules/net_tools/haproxy.py
patchback[bot] 5170c26ffd
multiple modules 2: fixed markups in doc (#5237) (#5244) 
* multiple modules 2: fixed markups in doc

* Update plugins/modules/cloud/misc/proxmox_template.py

Co-authored-by: Felix Fontein <felix@fontein.de>

Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit 999fc475a2)

Co-authored-by: Alexei Znamensky <103110+russoz@users.noreply.github.com>
2022-09-06 08:05:25 +02:00

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#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright (c) 2014, Ravi Bhure <ravibhure@gmail.com>
# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
# SPDX-License-Identifier: GPL-3.0-or-later
from __future__ import absolute_import, division, print_function
__metaclass__ = type
DOCUMENTATION = r'''
---
module: haproxy
short_description: Enable, disable, and set weights for HAProxy backend servers using socket commands
author:
- Ravi Bhure (@ravibhure)
description:
- Enable, disable, drain and set weights for HAProxy backend servers using socket commands.
notes:
- Enable, disable and drain commands are restricted and can only be issued on
sockets configured for level 'admin'. For example, you can add the line
'stats socket /var/run/haproxy.sock level admin' to the general section of
haproxy.cfg. See U(http://haproxy.1wt.eu/download/1.5/doc/configuration.txt).
- Depends on netcat (C(nc)) being available; you need to install the appropriate
package for your operating system before this module can be used.
options:
backend:
description:
- Name of the HAProxy backend pool.
- If this parameter is unset, it will be auto-detected.
type: str
drain:
description:
- Wait until the server has no active connections or until the timeout
determined by wait_interval and wait_retries is reached.
- Continue only after the status changes to C(MAINT).
- This overrides the shutdown_sessions option.
type: bool
default: false
host:
description:
- Name of the backend host to change.
type: str
required: true
shutdown_sessions:
description:
- When disabling a 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. Overridden by the drain option.
type: bool
default: false
socket:
description:
- Path to the HAProxy socket file.
type: path
default: /var/run/haproxy.sock
state:
description:
- Desired state of the provided backend host.
- Note that C(drain) state was added in version 2.4.
- It is supported only by HAProxy version 1.5 or later,
- When used on versions < 1.5, it will be ignored.
type: str
required: true
choices: [ disabled, drain, enabled ]
agent:
description:
- Disable/enable agent checks (depending on I(state) value).
type: bool
default: false
version_added: 1.0.0
health:
description:
- Disable/enable health checks (depending on I(state) value).
type: bool
default: false
version_added: "1.0.0"
fail_on_not_found:
description:
- Fail whenever trying to enable/disable a backend host that does not exist.
type: bool
default: false
wait:
description:
- Wait until the server reports a status of C(UP) when I(state=enabled),
status of C(MAINT) when I(state=disabled) or status of C(DRAIN) when I(state=drain).
type: bool
default: false
wait_interval:
description:
- Number of seconds to wait between retries.
type: int
default: 5
wait_retries:
description:
- Number of times to check for status after changing the state.
type: int
default: 25
weight:
description:
- The value passed in argument.
- If the value ends with the C(%) sign, then the new weight will be
relative to the initially configured weight.
- Relative weights are only permitted between 0 and 100% and absolute
weights are permitted between 0 and 256.
type: str
'''
EXAMPLES = r'''
- name: Disable server in 'www' backend pool
community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
backend: www
- name: Disable server in 'www' backend pool, also stop health/agent checks
community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
health: true
agent: true
- name: Disable server without backend pool name (apply to all available backend pool)
community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
- name: Disable server, provide socket file
community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
socket: /var/run/haproxy.sock
backend: www
- name: Disable server, provide socket file, wait until status reports in maintenance
community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
socket: /var/run/haproxy.sock
backend: www
wait: true
# Place server in drain mode, providing a socket file. Then check the server's
# status every minute to see if it changes to maintenance mode, continuing if it
# does in an hour and failing otherwise.
- community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
socket: /var/run/haproxy.sock
backend: www
wait: true
drain: true
wait_interval: 60
wait_retries: 60
- name: Disable backend server in 'www' backend pool and drop open sessions to it
community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
backend: www
socket: /var/run/haproxy.sock
shutdown_sessions: true
- name: Disable server without backend pool name (apply to all available backend pool) but fail when the backend host is not found
community.general.haproxy:
state: disabled
host: '{{ inventory_hostname }}'
fail_on_not_found: true
- name: Enable server in 'www' backend pool
community.general.haproxy:
state: enabled
host: '{{ inventory_hostname }}'
backend: www
- name: Enable server in 'www' backend pool wait until healthy
community.general.haproxy:
state: enabled
host: '{{ inventory_hostname }}'
backend: www
wait: true
- name: Enable server in 'www' backend pool wait until healthy. Retry 10 times with intervals of 5 seconds to retrieve the health
community.general.haproxy:
state: enabled
host: '{{ inventory_hostname }}'
backend: www
wait: true
wait_retries: 10
wait_interval: 5
- name: Enable server in 'www' backend pool with change server(s) weight
community.general.haproxy:
state: enabled
host: '{{ inventory_hostname }}'
socket: /var/run/haproxy.sock
weight: 10
backend: www
- name: Set the server in 'www' backend pool to drain mode
community.general.haproxy:
state: drain
host: '{{ inventory_hostname }}'
socket: /var/run/haproxy.sock
backend: www
'''
import csv
import socket
import time
from string import Template
from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.common.text.converters import to_bytes, to_text
DEFAULT_SOCKET_LOCATION = "/var/run/haproxy.sock"
RECV_SIZE = 1024
ACTION_CHOICES = ['enabled', 'disabled', 'drain']
WAIT_RETRIES = 25
WAIT_INTERVAL = 5
######################################################################
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):
self.module = module
self.state = self.module.params['state']
self.host = self.module.params['host']
self.backend = self.module.params['backend']
self.weight = self.module.params['weight']
self.socket = self.module.params['socket']
self.shutdown_sessions = self.module.params['shutdown_sessions']
self.fail_on_not_found = self.module.params['fail_on_not_found']
self.agent = self.module.params['agent']
self.health = self.module.params['health']
self.wait = self.module.params['wait']
self.wait_retries = self.module.params['wait_retries']
self.wait_interval = self.module.params['wait_interval']
self._drain = self.module.params['drain']
self.command_results = {}
def execute(self, cmd, timeout=200, capture_output=True):
"""
Executes a HAProxy command by sending a message to a HAProxy's local
UNIX socket and waiting up to 'timeout' milliseconds for the response.
"""
self.client = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
self.client.connect(self.socket)
self.client.sendall(to_bytes('%s\n' % cmd))
result = b''
buf = b''
buf = self.client.recv(RECV_SIZE)
while buf:
result += buf
buf = self.client.recv(RECV_SIZE)
result = to_text(result, errors='surrogate_or_strict')
if capture_output:
self.capture_command_output(cmd, result.strip())
self.client.close()
return result
def capture_command_output(self, cmd, output):
"""
Capture the output for a command
"""
if 'command' not in self.command_results:
self.command_results['command'] = []
self.command_results['command'].append(cmd)
if 'output' not in self.command_results:
self.command_results['output'] = []
self.command_results['output'].append(output)
def discover_all_backends(self):
"""
Discover all entries with svname = 'BACKEND' and return a list of their corresponding
pxnames
"""
data = self.execute('show stat', 200, False).lstrip('# ')
r = csv.DictReader(data.splitlines())
return tuple(map(lambda d: d['pxname'], filter(lambda d: d['svname'] == 'BACKEND', r)))
def discover_version(self):
"""
Attempt to extract the haproxy version.
Return a tuple containing major and minor version.
"""
data = self.execute('show info', 200, False)
lines = data.splitlines()
line = [x for x in lines if 'Version:' in x]
try:
version_values = line[0].partition(':')[2].strip().split('.', 3)
version = (int(version_values[0]), int(version_values[1]))
except (ValueError, TypeError, IndexError):
version = None
return version
def execute_for_backends(self, cmd, pxname, svname, wait_for_status=None):
"""
Run some command on the specified backends. If no backends are provided they will
be discovered automatically (all backends)
"""
# Discover backends if none are given
if pxname is None:
backends = self.discover_all_backends()
else:
backends = [pxname]
# Run the command for each requested backend
for backend in backends:
# Fail when backends were not found
state = self.get_state_for(backend, svname)
if (self.fail_on_not_found) and state is None:
self.module.fail_json(
msg="The specified backend '%s/%s' was not found!" % (backend, svname))
if state is not None:
self.execute(Template(cmd).substitute(pxname=backend, svname=svname))
if self.wait:
self.wait_until_status(backend, svname, wait_for_status)
def get_state_for(self, pxname, svname):
"""
Find the state of specific services. When pxname is not set, get all backends for a specific host.
Returns a list of dictionaries containing the status and weight for those services.
"""
data = self.execute('show stat', 200, False).lstrip('# ')
r = csv.DictReader(data.splitlines())
state = tuple(
map(
lambda d: {'status': d['status'], 'weight': d['weight'], 'scur': d['scur']},
filter(lambda d: (pxname is None or d['pxname']
== pxname) and d['svname'] == svname, r)
)
)
return state or None
def wait_until_status(self, pxname, svname, status):
"""
Wait for a service to reach the specified status. Try RETRIES times
with INTERVAL seconds of sleep in between. If the service has not reached
the expected status in that time, the module will fail. If the service was
not found, the module will fail.
"""
for i in range(1, self.wait_retries):
state = self.get_state_for(pxname, svname)
# We can assume there will only be 1 element in state because both svname and pxname are always set when we get here
# When using track we get a status like this: MAINT (via pxname/svname) so we need to do substring matching
if status in state[0]['status']:
if not self._drain or state[0]['scur'] == '0':
return True
time.sleep(self.wait_interval)
self.module.fail_json(msg="server %s/%s not status '%s' after %d retries. Aborting." %
(pxname, svname, status, self.wait_retries))
def enabled(self, host, backend, weight):
"""
Enabled action, marks server to UP and checks are re-enabled,
also supports to get current weight for server (default) and
set the weight for haproxy backend server when provides.
"""
cmd = "get weight $pxname/$svname; enable server $pxname/$svname"
if self.agent:
cmd += "; enable agent $pxname/$svname"
if self.health:
cmd += "; enable health $pxname/$svname"
if weight:
cmd += "; set weight $pxname/$svname %s" % weight
self.execute_for_backends(cmd, backend, host, 'UP')
def disabled(self, host, backend, shutdown_sessions):
"""
Disabled action, marks server to DOWN for maintenance. In this mode, no more checks will be
performed on the server until it leaves maintenance,
also it shutdown sessions while disabling backend host server.
"""
cmd = "get weight $pxname/$svname"
if self.agent:
cmd += "; disable agent $pxname/$svname"
if self.health:
cmd += "; disable health $pxname/$svname"
cmd += "; disable server $pxname/$svname"
if shutdown_sessions:
cmd += "; shutdown sessions server $pxname/$svname"
self.execute_for_backends(cmd, backend, host, 'MAINT')
def drain(self, host, backend, status='DRAIN'):
"""
Drain action, sets the server to DRAIN mode.
In this mode, the server will not accept any new connections
other than those that are accepted via persistence.
"""
haproxy_version = self.discover_version()
# check if haproxy version supports DRAIN state (starting with 1.5)
if haproxy_version and (1, 5) <= haproxy_version:
cmd = "set server $pxname/$svname state drain"
self.execute_for_backends(cmd, backend, host, "DRAIN")
if status == "MAINT":
self.disabled(host, backend, self.shutdown_sessions)
def act(self):
"""
Figure out what you want to do from ansible, and then do it.
"""
# Get the state before the run
self.command_results['state_before'] = self.get_state_for(self.backend, self.host)
# toggle enable/disable server
if self.state == 'enabled':
self.enabled(self.host, self.backend, self.weight)
elif self.state == 'disabled' and self._drain:
self.drain(self.host, self.backend, status='MAINT')
elif self.state == 'disabled':
self.disabled(self.host, self.backend, self.shutdown_sessions)
elif self.state == 'drain':
self.drain(self.host, self.backend)
else:
self.module.fail_json(msg="unknown state specified: '%s'" % self.state)
# Get the state after the run
self.command_results['state_after'] = self.get_state_for(self.backend, self.host)
# Report change status
self.command_results['changed'] = (self.command_results['state_before'] != self.command_results['state_after'])
self.module.exit_json(**self.command_results)
def main():
# load ansible module object
module = AnsibleModule(
argument_spec=dict(
state=dict(type='str', required=True, choices=ACTION_CHOICES),
host=dict(type='str', required=True),
backend=dict(type='str'),
weight=dict(type='str'),
socket=dict(type='path', default=DEFAULT_SOCKET_LOCATION),
shutdown_sessions=dict(type='bool', default=False),
fail_on_not_found=dict(type='bool', default=False),
health=dict(type='bool', default=False),
agent=dict(type='bool', default=False),
wait=dict(type='bool', default=False),
wait_retries=dict(type='int', default=WAIT_RETRIES),
wait_interval=dict(type='int', default=WAIT_INTERVAL),
drain=dict(type='bool', default=False),
),
)
if not socket:
module.fail_json(msg="unable to locate haproxy socket")
ansible_haproxy = HAProxy(module)
ansible_haproxy.act()
if __name__ == '__main__':
main()
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