Merge pull request #23 from ravibhure/devel

Added module haproxy, to handle enable/disable backend server with shutdown_sessions feature in haproxy.

network/haproxy.py

@@ -0,0 +1,278 @@
+#!/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
+ACTION_CHOICES = ['enabled', 'disabled']
+
+######################################################################
+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):
+        """
+        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.
+        """
+        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):
+        """
+        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.
+        """
+        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)
+
+        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)
+
+    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)
+
+def main():
+
+    # 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),
+        ),
+
+    )
+    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(msg="unable to locate haproxy socket")
+
+    ##################################################################
+    required_one_of=[['state', 'host']]
+
+    ansible_haproxy = HAProxy(module, **module.params)
+    ansible_haproxy.act()
+    ##################################################################
+
+# import module snippets
+from ansible.module_utils.basic import *
+
+main()