New module to support BGP configuration management in IOS (#49121)

* ios_bgp initial push

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Added tests for ios_bgp

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Fixed docs

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Added space

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Fix Shippable Errors

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Fix Shippable Errors

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Add support for af_neighbor option

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Add support for af_neighbor option - 2

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Add support for af_neighbor option - 3

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Fix typo

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Refactor BGP

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Fix CI and previous reviews

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Add missing params documentation

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Remove previous tests

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Remove elements=dict from keys with type=list from args spec for element validation to pass

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Added function to validate input

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Fix sanity test failure

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Minor bug fixes

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Fix typo in fixture

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

* Add integration tests

Signed-off-by: NilashishC <nilashishchakraborty8@gmail.com>

lib/ansible/module_utils/network/ios/providers/providers.py

@@ -0,0 +1,120 @@
+#
+# (c) 2019, Ansible by Red Hat, inc
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+#
+import json
+
+from threading import RLock
+
+from ansible.module_utils.six import itervalues
+from ansible.module_utils.network.common.utils import to_list
+from ansible.module_utils.network.common.config import NetworkConfig
+
+
+_registered_providers = {}
+_provider_lock = RLock()
+
+
+def register_provider(network_os, module_name):
+    def wrapper(cls):
+        _provider_lock.acquire()
+        try:
+            if network_os not in _registered_providers:
+                _registered_providers[network_os] = {}
+            for ct in cls.supported_connections:
+                if ct not in _registered_providers[network_os]:
+                    _registered_providers[network_os][ct] = {}
+            for item in to_list(module_name):
+                for entry in itervalues(_registered_providers[network_os]):
+                    entry[item] = cls
+        finally:
+            _provider_lock.release()
+        return cls
+    return wrapper
+
+
+def get(network_os, module_name, connection_type):
+    network_os_providers = _registered_providers.get(network_os)
+    if network_os_providers is None:
+        raise ValueError('unable to find a suitable provider for this module')
+    if connection_type not in network_os_providers:
+        raise ValueError('provider does not support this connection type')
+    elif module_name not in network_os_providers[connection_type]:
+        raise ValueError('could not find a suitable provider for this module')
+    return network_os_providers[connection_type][module_name]
+
+
+class ProviderBase(object):
+
+    supported_connections = ()
+
+    def __init__(self, params, connection=None, check_mode=False):
+        self.params = params
+        self.connection = connection
+        self.check_mode = check_mode
+
+    @property
+    def capabilities(self):
+        if not hasattr(self, '_capabilities'):
+            resp = self.from_json(self.connection.get_capabilities())
+            setattr(self, '_capabilities', resp)
+        return getattr(self, '_capabilities')
+
+    def get_value(self, path):
+        params = self.params.copy()
+        for key in path.split('.'):
+            params = params[key]
+        return params
+
+    def get_facts(self, subset=None):
+        raise NotImplementedError(self.__class__.__name__)
+
+    def edit_config(self):
+        raise NotImplementedError(self.__class__.__name__)
+
+
+class CliProvider(ProviderBase):
+
+    supported_connections = ('network_cli',)
+
+    @property
+    def capabilities(self):
+        if not hasattr(self, '_capabilities'):
+            resp = self.from_json(self.connection.get_capabilities())
+            setattr(self, '_capabilities', resp)
+        return getattr(self, '_capabilities')
+
+    def get_config_context(self, config, path, indent=1):
+        if config is not None:
+            netcfg = NetworkConfig(indent=indent, contents=config)
+            try:
+                config = netcfg.get_block_config(to_list(path))
+            except ValueError:
+                config = None
+            return config
+
+    def render(self, config=None):
+        raise NotImplementedError(self.__class__.__name__)
+
+    def cli(self, command):
+        try:
+            if not hasattr(self, '_command_output'):
+                setattr(self, '_command_output', {})
+            return self._command_output[command]
+        except KeyError:
+            out = self.connection.get(command)
+            try:
+                out = json.loads(out)
+            except ValueError:
+                pass
+            self._command_output[command] = out
+            return out
+
+    def get_facts(self, subset=None):
+        return self.populate()
+
+    def edit_config(self, config=None):
+        commands = self.render(config)
+        if commands and self.check_mode is False:
+            self.connection.edit_config(commands)
+        return commands