Clarify exception handling in net modules (#15507)

* Clarify exception handling in EOS

Also modify to EOS to standardize modules. It makes vimdiff a lot less angry

* Move IOS exception handling into Cli

* Move IOS-XR exception handling into Cli

* Move JUNOS exception handling into Cli

* Move NXOS exception handling into Cli

And reorganize to make it match the other modules

* Move OpenSwitch exception handling into Cli

More speculative restructuring here

lib/ansible/module_utils/junos.py

@@ -16,10 +16,11 @@
 # You should have received a copy of the GNU General Public License
 # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
 #
+
 from distutils.version import LooseVersion
 
-from ansible.module_utils.basic import AnsibleModule, env_fallback
-from ansible.module_utils.shell import Shell, HAS_PARAMIKO
+from ansible.module_utils.basic import AnsibleModule, env_fallback, get_exception
+from ansible.module_utils.shell import Shell, ShellError, HAS_PARAMIKO
 from ansible.module_utils.netcfg import parse
 
 try:
@@ -67,6 +68,7 @@ def to_list(val):
     else:
         return list()
 
+
 def xml_to_json(val):
     if isinstance(val, basestring):
         return jxmlease.parse(val)
@@ -91,13 +93,12 @@ class Cli(object):
         password = self.module.params['password']
         key_filename = self.module.params['ssh_keyfile']
 
-        self.shell = Shell()
-
         try:
-            self.shell.open(host, port=port, username=username,
-                    password=password, key_filename=key_filename)
-        except Exception, exc:
-            msg = 'failed to connect to %s:%s - %s' % (host, port, str(exc))
+            self.shell = Shell()
+            self.shell.open(host, port=port, username=username, password=password, key_filename=key_filename)
+        except ShellError:
+            e = get_exception()
+            msg = 'failed to connect to %s:%s - %s' % (host, port, str(e))
             self.module.fail_json(msg=msg)
 
         if self.shell._matched_prompt.strip().endswith('%'):
@@ -105,7 +106,11 @@ class Cli(object):
         self.shell.send('set cli screen-length 0')
 
     def run_commands(self, commands, **kwargs):
-        return self.shell.send(commands)
+        try:
+            return self.shell.send(commands)
+        except ShellError:
+            e = get_exception()
+            self.module.fail_json(msg=e.message, commands=commands)
 
     def configure(self, commands, **kwargs):
         commands = to_list(commands)
@@ -281,13 +286,18 @@ class NetworkModule(AnsibleModule):
         super(NetworkModule, self)._load_params()
         provider = self.params.get('provider') or dict()
         for key, value in provider.items():
-            if key in NET_COMMON_ARGS.keys():
+            if key in NET_COMMON_ARGS:
                 if self.params.get(key) is None and value is not None:
                     self.params[key] = value
 
     def connect(self):
         cls = globals().get(str(self.params['transport']).capitalize())
-        self.connection = cls(self)
+        try:
+            self.connection = cls(self)
+        except TypeError:
+            e = get_exception()
+            self.fail_json(msg=e.message)
+
         self.connection.connect()
 
         msg = 'connecting to host: {username}@{host}:{port}'.format(**self.params)
@@ -336,7 +346,6 @@ def get_module(**kwargs):
 
     module = NetworkModule(**kwargs)
 
-    # HAS_PARAMIKO is set by module_utils/shell.py
     if module.params['transport'] == 'cli' and not HAS_PARAMIKO:
         module.fail_json(msg='paramiko is required but does not appear to be installed')
     elif module.params['transport'] == 'netconf' and not HAS_PYEZ: