Add nso_show module for Cisco NSO (#34142)

* update version parsing and move requirements to nso_* modules

prepare for introduction of nso_show module that has other version
requirements than the existing nso_* modules.

* Add nso_show module for retreiving config from Cisco NSO

New module that supports getting configuration and operational data
from Cisco NSO.

lib/ansible/module_utils/network/nso/nso.py

@@ -159,6 +159,17 @@ class JsonRpc(object):
         resp, resp_json = self._write_call(payload)
         return resp_json['result']
 
+    def show_config(self, path, operational=False):
+        payload = {
+            'method': 'show_config',
+            'params': {
+                'path': path,
+                'result_as': 'json',
+                'with_oper': operational}
+        }
+        resp, resp_json = self._read_call(payload)
+        return resp_json['result']
+
     def run_action(self, th, path, params=None):
         if params is None:
             params = {}
@@ -481,16 +492,40 @@ def connect(params):
     return client
 
 
-def verify_version(client):
+def verify_version(client, required_versions=None):
+    if required_versions is None:
+        required_versions = [(4, 5), (4, 4, 3)]
+
     version_str = client.get_system_setting('version')
+    if not verify_version_str(version_str, required_versions):
+        supported_versions = ', '.join(
+            ['.'.join([str(p) for p in required_version])
+             for required_version in required_versions])
+        raise ModuleFailException(
+            'unsupported NSO version {0}. {1} or later supported'.format(
+                version_str, supported_versions))
+
+
+def verify_version_str(version_str, required_versions):
     version = [int(p) for p in version_str.split('.')]
     if len(version) < 2:
         raise ModuleFailException(
             'unsupported NSO version format {0}'.format(version_str))
-    if (version[0] < 4 or version[1] < 4 or
-            (version[1] == 4 and (len(version) < 3 or version[2] < 3))):
-        raise ModuleFailException(
-            'unsupported NSO version {0}, only 4.4.3 or later is supported'.format(version_str))
+
+    def check_version(required_version, version):
+        for pos in range(len(required_version)):
+            if pos >= len(version):
+                return False
+            if version[pos] > required_version[pos]:
+                return True
+            if version[pos] < required_version[pos]:
+                return False
+        return True
+
+    for required_version in required_versions:
+        if check_version(required_version, version):
+            return True
+    return False
 
 
 def normalize_value(expected_value, value, key):