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fail when backend host is not found (#1385)

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reviewable/pr18780/r1
Gerrit Germis 9 years ago committed by Brian Coca
parent 8fac01a3cc
commit a003b8d081
1 changed files with 100 additions and 117 deletions
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217
network/haproxy.py
Unescape Escape View File

@ -60,6 +60,12 @@ options:
required: true
default: null
choices: [ "enabled", "disabled" ]
fail_on_not_found:
description:
- Fail whenever trying to enable/disable a backend host that does not exist
required: false
default: false
version_added: "2.2"
wait:
description:
- Wait until the server reports a status of 'UP' when `state=enabled`, or
@ -105,6 +111,9 @@ EXAMPLES = '''
# 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
# disable server without backend pool name (apply to all available backend pool) but fail when the backend host is not found
- haproxy: state=disabled host={{ inventory_hostname }} fail_on_not_found=yes
# enable server in 'www' backend pool
- haproxy: state=enabled host={{ inventory_hostname }} backend=www
@ -123,6 +132,7 @@ author: "Ravi Bhure (@ravibhure)"
import socket
import csv
import time
from string import Template
DEFAULT_SOCKET_LOCATION="/var/run/haproxy.sock"
@ -156,23 +166,17 @@ class HAProxy(object):
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.wait = self.module.params['wait']
self.wait_retries = self.module.params['wait_retries']
self.wait_interval = self.module.params['wait_interval']
self.command_results = []
self.status_servers = []
self.status_weights = []
self.previous_weights = []
self.previous_states = []
self.current_states = []
self.current_weights = []
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('%s\n' % cmd)
@ -183,10 +187,67 @@ class HAProxy(object):
result += buf
buf = self.client.recv(RECV_SIZE)
if capture_output:
self.command_results = result.strip()
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 not 'command' in self.command_results.keys():
self.command_results['command'] = []
self.command_results['command'].append(cmd)
if not 'output' in self.command_results.keys():
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 map(lambda d: d['pxname'], filter(lambda d: d['svname'] == 'BACKEND', r))
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 or self.wait) and state is None:
self.module.fail_json(msg="The specified backend '%s/%s' was not found!" % (backend, svname))
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 = map(lambda d: { 'status': d['status'], 'weight': d['weight'] }, 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
@ -195,49 +256,16 @@ class HAProxy(object):
not found, the module will fail.
"""
for i in range(1, self.wait_retries):
data = self.execute('show stat', 200, False).lstrip('# ')
r = csv.DictReader(data.splitlines())
found = False
for row in r:
if row['pxname'] == pxname and row['svname'] == svname:
found = True
if row['status'] == status:
return True;
else:
time.sleep(self.wait_interval)
if not found:
self.module.fail_json(msg="unable to find server %s/%s" % (pxname, svname))
state = self.get_state_for(pxname, svname)
self.module.fail_json(msg="server %s/%s not status '%s' after %d retries. Aborting." % (pxname, svname, status, self.wait_retries))
# We can assume there will only be 1 element in state because both svname and pxname are always set when we get here
if state[0]['status'] == status:
return True
else:
time.sleep(self.wait_interval)
def get_current_state(self, host, backend):
"""
Gets the each original state value from show stat.
Runs before and after to determine if values are changed.
This relies on weight always being the next element after
status in "show stat" as well as status states remaining
as indicated in status_states and haproxy documentation.
"""
output = self.execute('show stat')
output = output.lstrip('# ').strip()
output = output.split(',')
result = output
status_states = [ 'UP','DOWN','DRAIN','NOLB','MAINT' ]
self.status_server = []
status_weight_pos = []
self.status_weight = []
for check, status in enumerate(result):
if status in status_states:
self.status_server.append(status)
status_weight_pos.append(check + 1)
for weight in status_weight_pos:
self.status_weight.append(result[weight])
self.module.fail_json(msg="server %s/%s not status '%s' after %d retries. Aborting." % (pxname, svname, status, self.wait_retries))
return{'self.status_server':self.status_server, 'self.status_weight':self.status_weight}
def enabled(self, host, backend, weight):
"""
@ -245,33 +273,11 @@ class HAProxy(object):
also supports to get current weight for server (default) and
set the weight for haproxy backend server when provides.
"""
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)
if self.wait:
self.wait_until_status(pxname, svname, 'UP')
cmd = "get weight $pxname/$svname; enable server $pxname/$svname"
if weight:
cmd += "; set weight $pxname/$svname %s" % weight
self.execute_for_backends(cmd, backend, host, 'UP')
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)
if self.wait:
self.wait_until_status(pxname, svname, 'UP')
def disabled(self, host, backend, shutdown_sessions):
"""
@ -279,64 +285,40 @@ class HAProxy(object):
performed on the server until it leaves maintenance,
also it shutdown sessions while disabling backend host server.
"""
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:
cmd += "; shutdown sessions server %s/%s" % (pxname, svname)
self.execute(cmd)
if self.wait:
self.wait_until_status(pxname, svname, 'MAINT')
cmd = "get weight $pxname/$svname; disable server $pxname/$svname"
if shutdown_sessions:
cmd += "; shutdown sessions server $pxname/$svname"
self.execute_for_backends(cmd, backend, host, 'MAINT')
else:
pxname = backend
cmd = "get weight %s/%s ; disable server %s/%s" % (pxname, svname, pxname, svname)
if shutdown_sessions:
cmd += "; shutdown sessions server %s/%s" % (pxname, svname)
self.execute(cmd)
if self.wait:
self.wait_until_status(pxname, svname, 'MAINT')
def act(self):
"""
Figure out what you want to do from ansible, and then do it.
"""
self.get_current_state(self.host, self.backend)
self.previous_states = ','.join(self.status_server)
self.previous_weights = ','.join(self.status_weight)
# Get the state before the run
state_before = self.get_state_for(self.backend, self.host)
self.command_results['state_before'] = state_before
# 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.get_current_state(self.host, self.backend)
self.current_states = ','.join(self.status_server)
self.current_weights = ','.join(self.status_weight)
# Get the state after the run
state_after = self.get_state_for(self.backend, self.host)
self.command_results['state_after'] = state_after
if self.current_weights != self.previous_weights:
self.module.exit_json(stdout=self.command_results, changed=True)
elif self.current_states != self.previous_states:
self.module.exit_json(stdout=self.command_results, changed=True)
# Report change status
if state_before != state_after:
self.command_results['changed'] = True
self.module.exit_json(**self.command_results)
else:
self.module.exit_json(stdout=self.command_results, changed=False)
self.command_results['changed'] = False
self.module.exit_json(**self.command_results)
def main():
@ -349,11 +331,11 @@ def main():
weight=dict(required=False, default=None),
socket = dict(required=False, default=DEFAULT_SOCKET_LOCATION),
shutdown_sessions=dict(required=False, default=False),
fail_on_not_found=dict(required=False, default=False, type='bool'),
wait=dict(required=False, default=False, type='bool'),
wait_retries=dict(required=False, default=WAIT_RETRIES, type='int'),
wait_interval=dict(required=False, default=WAIT_INTERVAL, type='int'),
),
)
if not socket:
@ -366,3 +348,4 @@ def main():
from ansible.module_utils.basic import *
main()

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