new module: apache2_mod_proxy (#2148)

* module apache2_mod_proxy

* Moved state notes to state description.

web_infrastructure/apache2_mod_proxy.py

@@ -0,0 +1,429 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# (c) 2016, Olivier Boukili <boukili.olivier@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: apache2_mod_proxy
+version_added: "2.2"
+short_description: Set and/or get members' attributes of an Apache httpd 2.4 mod_proxy balancer pool
+description:
+  - Set and/or get members' attributes of an Apache httpd 2.4 mod_proxy balancer
+    pool, using HTTP POST and GET requests. The httpd mod_proxy balancer-member
+    status page has to be enabled and accessible, as this module relies on parsing
+    this page. This module supports ansible check_mode, and requires BeautifulSoup
+    python module.
+options:
+  balancer_url_suffix:
+    default: /balancer-manager/
+    description:
+      - Suffix of the balancer pool url required to access the balancer pool
+        status page (e.g. balancer_vhost[:port]/balancer_url_suffix).
+    required: false
+  balancer_vhost:
+    default: None
+    description:
+      - (ipv4|ipv6|fqdn):port of the Apache httpd 2.4 mod_proxy balancer pool.
+    required: true
+  member_host:
+    default: None
+    description:
+      - (ipv4|ipv6|fqdn) of the balancer member to get or to set attributes to.
+        Port number is autodetected and should not be specified here.
+        If undefined, apache2_mod_proxy module will return a members list of
+        dictionaries of all the current balancer pool members' attributes.
+    required: false
+  state:
+    default: None
+    description:
+      - Desired state of the member host.
+        (absent|disabled),drained,hot_standby,ignore_errors can be
+        simultaneously invoked by separating them with a comma (e.g. state=drained,ignore_errors).
+    required: false
+    choices: ["present", "absent", "enabled", "disabled", "drained", "hot_standby", "ignore_errors"]
+  tls:
+    default: false
+    description:
+      - Use https to access balancer management page.
+    choices: ["true", "false"]
+  validate_certs:
+    default: true
+    description:
+      - Validate ssl/tls certificates.
+    choices: ["true", "false"]
+'''
+
+EXAMPLES = '''
+# Get all current balancer pool members' attributes:
+- apache2_mod_proxy: balancer_vhost=10.0.0.2
+
+# Get a specific member's attributes:
+- apache2_mod_proxy: balancer_vhost=myws.mydomain.org balancer_suffix="/lb/" member_host=node1.myws.mydomain.org
+
+# Enable all balancer pool members:
+- apache2_mod_proxy: balancer_vhost="{{ myloadbalancer_host }}"
+  register: result
+- apache2_mod_proxy: balancer_vhost="{{ myloadbalancer_host }}" member_host="{{ item.host }}" state=present
+  with_items: "{{ result.members }}"
+
+# Gracefully disable a member from a loadbalancer node:
+- apache2_mod_proxy: balancer_vhost="{{ vhost_host }}" member_host="{{ member.host }}" state=drained delegate_to=myloadbalancernode
+- wait_for: host="{{ member.host }}" port={{ member.port }} state=drained delegate_to=myloadbalancernode
+- apache2_mod_proxy: balancer_vhost="{{ vhost_host }}" member_host="{{ member.host }}" state=absent delegate_to=myloadbalancernode
+'''
+
+RETURN = '''
+member:
+    description: specific balancer member information dictionary, returned when apache2_mod_proxy module is invoked with member_host parameter.
+    type: dict
+    returned: success
+    sample:
+      {"attributes":
+            {"Busy": "0",
+            "Elected": "42",
+            "Factor": "1",
+            "From": "136K",
+            "Load": "0",
+            "Route": null,
+            "RouteRedir": null,
+            "Set": "0",
+            "Status": "Init Ok ",
+            "To": " 47K",
+            "Worker URL": null
+        },
+        "balancer_url": "http://10.10.0.2/balancer-manager/",
+        "host": "10.10.0.20",
+        "management_url": "http://10.10.0.2/lb/?b=mywsbalancer&w=http://10.10.0.20:8080/ws&nonce=8925436c-79c6-4841-8936-e7d13b79239b",
+        "path": "/ws",
+        "port": 8080,
+        "protocol": "http",
+        "status": {
+            "disabled": false,
+            "drained": false,
+            "hot_standby": false,
+            "ignore_errors": false
+        }
+      }
+members:
+    description: list of member (defined above) dictionaries, returned when apache2_mod_proxy is invoked with no member_host and state args.
+    returned: success
+    type: list
+    sample:
+      [{"attributes": {
+            "Busy": "0",
+            "Elected": "42",
+            "Factor": "1",
+            "From": "136K",
+            "Load": "0",
+            "Route": null,
+            "RouteRedir": null,
+            "Set": "0",
+            "Status": "Init Ok ",
+            "To": " 47K",
+            "Worker URL": null
+        },
+        "balancer_url": "http://10.10.0.2/balancer-manager/",
+        "host": "10.10.0.20",
+        "management_url": "http://10.10.0.2/lb/?b=mywsbalancer&w=http://10.10.0.20:8080/ws&nonce=8925436c-79c6-4841-8936-e7d13b79239b",
+        "path": "/ws",
+        "port": 8080,
+        "protocol": "http",
+        "status": {
+            "disabled": false,
+            "drained": false,
+            "hot_standby": false,
+            "ignore_errors": false
+        }
+        },
+        {"attributes": {
+            "Busy": "0",
+            "Elected": "42",
+            "Factor": "1",
+            "From": "136K",
+            "Load": "0",
+            "Route": null,
+            "RouteRedir": null,
+            "Set": "0",
+            "Status": "Init Ok ",
+            "To": " 47K",
+            "Worker URL": null
+        },
+        "balancer_url": "http://10.10.0.2/balancer-manager/",
+        "host": "10.10.0.21",
+        "management_url": "http://10.10.0.2/lb/?b=mywsbalancer&w=http://10.10.0.21:8080/ws&nonce=8925436c-79c6-4841-8936-e7d13b79239b",
+        "path": "/ws",
+        "port": 8080,
+        "protocol": "http",
+        "status": {
+            "disabled": false,
+            "drained": false,
+            "hot_standby": false,
+            "ignore_errors": false}
+        }
+      ]
+'''
+
+import re
+
+try:
+    from BeautifulSoup import BeautifulSoup
+except ImportError:
+    HAS_BEAUTIFULSOUP = False
+else:
+    HAS_BEAUTIFULSOUP = True
+
+# balancer member attributes extraction regexp:
+EXPRESSION = r"(b=([\w\.\-]+)&w=(https?|ajp|wss?|ftp|[sf]cgi)://([\w\.\-]+):?(\d*)([/\w\.\-]*)&?[\w\-\=]*)"
+# Apache2 server version extraction regexp:
+APACHE_VERSION_EXPRESSION = r"Server Version: Apache/([\d.]+) \(([\w]+)\)"
+
+def regexp_extraction(string, _regexp, groups=1):
+    """ Returns the capture group (default=1) specified in the regexp, applied to the string """
+    regexp_search = re.search(string=str(string), pattern=str(_regexp))
+    if regexp_search:
+        if regexp_search.group(groups) != '':
+            return str(regexp_search.group(groups))
+    return None
+
+class BalancerMember(object):
+    """ Apache 2.4 mod_proxy LB balancer member.
+    attributes:
+        read-only:
+            host -> member host (string),
+            management_url -> member management url (string),
+            protocol -> member protocol (string)
+            port -> member port (string),
+            path -> member location (string),
+            balancer_url -> url of this member's parent balancer (string),
+            attributes -> whole member attributes (dictionary)
+            module -> ansible module instance (AnsibleModule object).
+        writable:
+            status -> status of the member (dictionary)
+    """
+
+    def __init__(self, management_url, balancer_url, module):
+        self.host = regexp_extraction(management_url, str(EXPRESSION), 4)
+        self.management_url = str(management_url)
+        self.protocol = regexp_extraction(management_url, EXPRESSION, 3)
+        self.port = regexp_extraction(management_url, EXPRESSION, 5)
+        self.path = regexp_extraction(management_url, EXPRESSION, 6)
+        self.balancer_url = str(balancer_url)
+        self.module = module
+
+    def get_member_attributes(self):
+        """ Returns a dictionary of a balancer member's attributes."""
+
+        balancer_member_page = fetch_url(self.module, self.management_url)
+
+        try:
+            assert balancer_member_page[1]['status'] == 200
+        except AssertionError:
+            self.module.fail_json(msg="Could not get balancer_member_page, check for connectivity! " + balancer_member_page[1])
+        else:
+            try:
+                soup = BeautifulSoup(balancer_member_page[0])
+            except TypeError:
+                self.module.fail_json(msg="Cannot parse balancer_member_page HTML! " + str(soup))
+            else:
+                subsoup = soup.findAll('table')[1].findAll('tr')
+                keys = subsoup[0].findAll('th')
+                for valuesset in subsoup[1::1]:
+                    if re.search(pattern=self.host, string=str(valuesset)):
+                        values = valuesset.findAll('td')
+                        return dict((keys[x].string, values[x].string) for x in range(0, len(keys)))
+
+    def get_member_status(self):
+        """ Returns a dictionary of a balancer member's status attributes."""
+        status_mapping = {'disabled':'Dis',
+                          'drained':'Drn',
+                          'hot_standby':'Stby',
+                          'ignore_errors':'Ign'}
+        status = {}
+        actual_status = str(self.attributes['Status'])
+        for mode in status_mapping.keys():
+            if re.search(pattern=status_mapping[mode], string=actual_status):
+                status[mode] = True
+            else:
+                status[mode] = False
+        return status
+
+    def set_member_status(self, values):
+        """ Sets a balancer member's status attributes amongst pre-mapped values."""
+        values_mapping = {'disabled':'&w_status_D',
+                          'drained':'&w_status_N',
+                          'hot_standby':'&w_status_H',
+                          'ignore_errors':'&w_status_I'}
+
+        request_body = regexp_extraction(self.management_url, EXPRESSION, 1)
+        for k in values_mapping.keys():
+            if values[str(k)]:
+                request_body = request_body + str(values_mapping[k]) + '=1'
+            else:
+                request_body = request_body + str(values_mapping[k]) + '=0'
+
+        response = fetch_url(self.module, self.management_url, data=str(request_body))
+        try:
+            assert response[1]['status'] == 200
+        except AssertionError:
+            self.module.fail_json(msg="Could not set the member status! " + self.host + " " + response[1]['status'])
+
+    attributes = property(get_member_attributes)
+    status = property(get_member_status, set_member_status)
+
+
+class Balancer(object):
+    """ Apache httpd 2.4 mod_proxy balancer object"""
+    def __init__(self, host, suffix, module, members=None, tls=False):
+        if tls:
+            self.base_url = str(str('https://') + str(host))
+            self.url = str(str('https://') + str(host) + str(suffix))
+        else:
+            self.base_url = str(str('http://') + str(host))
+            self.url = str(str('http://') + str(host) + str(suffix))
+        self.module = module
+        self.page = self.fetch_balancer_page()
+        if members is None:
+            self._members = []
+
+    def fetch_balancer_page(self):
+        """ Returns the balancer management html page as a string for later parsing."""
+        page = fetch_url(self.module, str(self.url))
+        try:
+            assert page[1]['status'] == 200
+        except AssertionError:
+            self.module.fail_json(msg="Could not get balancer page! HTTP status response: " + str(page[1]['status']))
+        else:
+            content = page[0].read()
+            apache_version = regexp_extraction(content, APACHE_VERSION_EXPRESSION, 1)
+            if not re.search(pattern=r"2\.4\.[\d]*", string=apache_version):
+                self.module.fail_json(msg="This module only acts on an Apache2 2.4+ instance, current Apache2 version: " + str(apache_version))
+            return content
+
+    def get_balancer_members(self):
+        """ Returns members of the balancer as a generator object for later iteration."""
+        try:
+            soup = BeautifulSoup(self.page)
+        except TypeError:
+            self.module.fail_json(msg="Cannot parse balancer page HTML! " + str(self.page))
+        else:
+            for element in soup.findAll('a')[1::1]:
+                balancer_member_suffix = str(element.get('href'))
+                try:
+                    assert balancer_member_suffix is not ''
+                except AssertionError:
+                    self.module.fail_json(msg="Argument 'balancer_member_suffix' is empty!")
+                else:
+                    yield BalancerMember(str(self.base_url + balancer_member_suffix), str(self.url), self.module)
+
+    members = property(get_balancer_members)
+
+def main():
+    """ Initiates module."""
+    module = AnsibleModule(
+        argument_spec=dict(
+            balancer_vhost=dict(required=True, default=None, type='str'),
+            balancer_url_suffix=dict(default="/balancer-manager/", type='str'),
+            member_host=dict(type='str'),
+            state=dict(type='str'),
+            tls=dict(default=False, type='bool'),
+            validate_certs=dict(default=True, type='bool')
+        ),
+        supports_check_mode=True
+    )
+
+    if HAS_BEAUTIFULSOUP is False:
+        module.fail_json(msg="python module 'BeautifulSoup' is required!")
+
+    if module.params['state'] != None:
+        states = module.params['state'].split(',')
+        if (len(states) > 1) and (("present" in states) or ("enabled" in states)):
+            module.fail_json(msg="state present/enabled is mutually exclusive with other states!")
+        else:
+            for _state in states:
+                if _state not in ['present', 'absent', 'enabled', 'disabled', 'drained', 'hot_standby', 'ignore_errors']:
+                    module.fail_json(msg="State can only take values amongst 'present', 'absent', 'enabled', 'disabled', 'drained', 'hot_standby', 'ignore_errors'.")
+    else:
+        states = ['None']
+
+    mybalancer = Balancer(module.params['balancer_vhost'],
+                          module.params['balancer_url_suffix'],
+                          module=module,
+                          tls=module.params['tls'])
+
+    if module.params['member_host'] is None:
+        json_output_list = []
+        for member in mybalancer.members:
+            json_output_list.append({
+                "host": member.host,
+                "status": member.status,
+                "protocol": member.protocol,
+                "port": member.port,
+                "path": member.path,
+                "attributes": member.attributes,
+                "management_url": member.management_url,
+                "balancer_url": member.balancer_url
+            })
+        module.exit_json(
+            changed=False,
+            members=json_output_list
+        )
+    else:
+        changed = False
+        member_exists = False
+        member_status = {'disabled': False, 'drained': False, 'hot_standby': False, 'ignore_errors':False}
+        for mode in member_status.keys():
+            for state in states:
+                if mode == state:
+                    member_status[mode] = True
+                elif mode == 'disabled' and state == 'absent':
+                    member_status[mode] = True
+
+        for member in mybalancer.members:
+            if str(member.host) == str(module.params['member_host']):
+                member_exists = True
+                if module.params['state'] is not None:
+                    member_status_before = member.status
+                    if not module.check_mode:
+                        member_status_after = member.status = member_status
+                    else:
+                        member_status_after = member_status
+                    if member_status_before != member_status_after:
+                        changed = True
+                json_output = {
+                    "host": member.host,
+                    "status": member.status,
+                    "protocol": member.protocol,
+                    "port": member.port,
+                    "path": member.path,
+                    "attributes": member.attributes,
+                    "management_url": member.management_url,
+                    "balancer_url": member.balancer_url
+                }
+        if member_exists:
+            module.exit_json(
+                changed=changed,
+                member=json_output
+                )
+        else:
+            module.fail_json(msg=str(module.params['member_host']) + ' is not a member of the balancer ' + str(module.params['balancer_vhost']) + '!')
+
+from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils.urls import fetch_url
+if __name__ == '__main__':
+    main()