ansible/clustering/consul_session

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#!/usr/bin/python
#
# (c) 2015, Steve Gargan <steve.gargan@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: consul_session
short_description: "manipulate consul sessions"
description:
- allows the addition, modification and deletion of sessions in a consul
cluster. These sessions can then be used in conjunction with key value pairs
to implement distributed locks. In depth documentation for working with
sessions can be found here http://www.consul.io/docs/internals/sessions.html
requirements:
- python-consul
- requests
version_added: "1.9"
author: Steve Gargan (steve.gargan@gmail.com)
options:
state:
description:
- whether the session should be present i.e. created if it doesn't
exist, or absent, removed if present. If created, the ID for the
session is returned in the output. If absent, the name or ID is
required to remove the session. Info for a single session, all the
sessions for a node or all available sessions can be retrieved by
specifying info, node or list for the state; for node or info, the
node name or session id is required as parameter.
required: false
choices: ['present', 'absent', 'info', 'node', 'list']
default: present
name:
description:
- the name that should be associated with the session. This is opaque
to Consul and not required.
required: false
default: None
delay:
description:
- the optional lock delay that can be attached to the session when it
is created. Locks for invalidated sessions ar blocked from being
acquired until this delay has expired. Valid units for delays
include 'ns', 'us', 'ms', 's', 'm', 'h'
default: 15s
required: false
node:
description:
- the name of the node that with which the session will be associated.
by default this is the name of the agent.
required: false
default: None
datacenter:
description:
- name of the datacenter in which the session exists or should be
created.
required: false
default: None
checks:
description:
- a list of checks that will be used to verify the session health. If
all the checks fail, the session will be invalidated and any locks
associated with the session will be release and can be acquired once
the associated lock delay has expired.
required: false
default: None
host:
description:
- host of the consul agent defaults to localhost
required: false
default: localhost
port:
description:
- the port on which the consul agent is running
required: false
default: 8500
"""
EXAMPLES = '''
- name: register basic session with consul
consul_session:
name: session1
- name: register a session with an existing check
consul_session:
name: session_with_check
checks:
- existing_check_name
- name: register a session with lock_delay
consul_session:
name: session_with_delay
delay: 20s
- name: retrieve info about session by id
consul_session: id=session_id state=info
- name: retrieve active sessions
consul_session: state=list
'''
import sys
import urllib2
try:
import consul
from requests.exceptions import ConnectionError
python_consul_installed = True
except ImportError, e:
python_consul_installed = False
def execute(module):
state = module.params.get('state')
if state in ['info', 'list', 'node']:
lookup_sessions(module)
elif state == 'present':
update_session(module)
else:
remove_session(module)
def lookup_sessions(module):
datacenter = module.params.get('datacenter')
state = module.params.get('state')
consul = get_consul_api(module)
try:
if state == 'list':
sessions_list = consul.session.list(dc=datacenter)
#ditch the index, this can be grabbed from the results
if sessions_list and sessions_list[1]:
sessions_list = sessions_list[1]
module.exit_json(changed=True,
sessions=sessions_list)
elif state == 'node':
node = module.params.get('node')
if not node:
module.fail_json(
msg="node name is required to retrieve sessions for node")
sessions = consul.session.node(node, dc=datacenter)
module.exit_json(changed=True,
node=node,
sessions=sessions)
elif state == 'info':
session_id = module.params.get('id')
if not session_id:
module.fail_json(
msg="session_id is required to retrieve indvidual session info")
session_by_id = consul.session.info(session_id, dc=datacenter)
module.exit_json(changed=True,
session_id=session_id,
sessions=session_by_id)
except Exception, e:
module.fail_json(msg="Could not retrieve session info %s" % e)
def update_session(module):
name = module.params.get('name')
session_id = module.params.get('id')
delay = module.params.get('delay')
checks = module.params.get('checks')
datacenter = module.params.get('datacenter')
node = module.params.get('node')
consul = get_consul_api(module)
changed = True
try:
session = consul.session.create(
name=name,
node=node,
lock_delay=validate_duration('delay', delay),
dc=datacenter,
checks=checks
)
module.exit_json(changed=True,
session_id=session,
name=name,
delay=delay,
checks=checks,
node=node)
except Exception, e:
module.fail_json(msg="Could not create/update session %s" % e)
def remove_session(module):
session_id = module.params.get('id')
if not session_id:
module.fail_json(msg="""A session id must be supplied in order to
remove a session.""")
consul = get_consul_api(module)
changed = False
try:
session = consul.session.destroy(session_id)
module.exit_json(changed=True,
session_id=session_id)
except Exception, e:
module.fail_json(msg="Could not remove session with id '%s' %s" % (
session_id, e))
def validate_duration(name, duration):
if duration:
duration_units = ['ns', 'us', 'ms', 's', 'm', 'h']
if not any((duration.endswith(suffix) for suffix in duration_units)):
raise Exception('Invalid %s %s you must specify units (%s)' %
(name, duration, ', '.join(duration_units)))
return duration
def get_consul_api(module):
return consul.Consul(host=module.params.get('host'),
port=module.params.get('port'))
def test_dependencies(module):
if not python_consul_installed:
module.fail_json(msg="python-consul required for this module. "\
"see http://python-consul.readthedocs.org/en/latest/#installation")
def main():
argument_spec = dict(
checks=dict(default=None, required=False, type='list'),
delay=dict(required=False,type='str', default='15s'),
host=dict(default='localhost'),
port=dict(default=8500, type='int'),
id=dict(required=False),
name=dict(required=False),
node=dict(required=False),
state=dict(default='present',
choices=['present', 'absent', 'info', 'node', 'list'])
)
module = AnsibleModule(argument_spec, supports_check_mode=False)
test_dependencies(module)
try:
execute(module)
except ConnectionError, e:
module.fail_json(msg='Could not connect to consul agent at %s:%s, error was %s' % (
module.params.get('host'), module.params.get('port'), str(e)))
except Exception, e:
module.fail_json(msg=str(e))
# import module snippets
from ansible.module_utils.basic import *
main()