Add netconf_get module (#39869)

* Add netconf_get module

Implements part-1 of proposal #104
https://github.com/ansible/proposals/issues/104

*  Add netconf_get module
*  Refactor `get`, `get_config`, `lock`, `unlock`
   and `discard_changes` netconf plugin api's
*  Add netconf module_utils file which netconf module
   related common functions
*  Refactor junos and iosxr netconf plugins

* Fix source option handling

* Fix review comments

* Update botmeta file

* Update review comments and add support for lock

* Lock update fix

* Fix CI issue

* Add integration test and minor fixes

* Fix review comments

* Fix CI failure

* Fix CI issues

* Fix CI issues

* Fix review comments and update integration test

* Fix review comments

* Fix review comments

* Fix review comments

Fix reveiw comments

lib/ansible/module_utils/network/netconf/netconf.py

@@ -0,0 +1,106 @@
+#
+# (c) 2018 Red Hat, Inc.
+#
+# 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/>.
+#
+import json
+
+from contextlib import contextmanager
+
+from ansible.module_utils._text import to_text
+from ansible.module_utils.connection import Connection, ConnectionError
+from ansible.module_utils.network.common.netconf import NetconfConnection
+
+
+def get_connection(module):
+    if hasattr(module, '_netconf_connection'):
+        return module._netconf_connection
+
+    capabilities = get_capabilities(module)
+    network_api = capabilities.get('network_api')
+    if network_api == 'netconf':
+        module._netconf_connection = NetconfConnection(module._socket_path)
+    else:
+        module.fail_json(msg='Invalid connection type %s' % network_api)
+
+    return module._netconf_connection
+
+
+def get_capabilities(module):
+    if hasattr(module, '_netconf_capabilities'):
+        return module._netconf_capabilities
+
+    capabilities = Connection(module._socket_path).get_capabilities()
+    module._netconf_capabilities = json.loads(capabilities)
+    return module._netconf_capabilities
+
+
+def lock_configuration(x, target=None):
+    conn = get_connection(x)
+    return conn.lock(target=target)
+
+
+def unlock_configuration(x, target=None):
+    conn = get_connection(x)
+    return conn.unlock(target=target)
+
+
+@contextmanager
+def locked_config(module, target=None):
+    try:
+        lock_configuration(module, target=target)
+        yield
+    finally:
+        unlock_configuration(module, target=target)
+
+
+def get_config(module, source, filter, lock=False):
+    conn = get_connection(module)
+    try:
+        locked = False
+        if lock:
+            conn.lock(target='running')
+            locked = True
+        response = conn.get_config(source=source, filter=filter)
+
+    except ConnectionError as e:
+        module.fail_json(msg=to_text(e, errors='surrogate_then_replace').strip())
+
+    finally:
+        if locked:
+            conn.unlock(target='running')
+
+    return response
+
+
+def get(module, filter, lock=False):
+    conn = get_connection(module)
+    try:
+        locked = False
+        if lock:
+            conn.lock(target='running')
+            locked = True
+
+        response = conn.get(filter=filter)
+
+    except ConnectionError as e:
+        module.fail_json(msg=to_text(e, errors='surrogate_then_replace').strip())
+
+    finally:
+        if locked:
+            conn.unlock(target='running')
+
+    return response