Add a module for ssh 'console' API

Create a module that does ssh and treats it like
a console.  The plan is to have a cliserver.py to
behave in a manner resembling consoleserver.py, but
with option to have multiple distinct sessions per
target.

confluent_server/confluent/plugins/shell/ssh.py

@@ -0,0 +1,103 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2015 Lenovo
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+__author__ = 'jjohnson2'
+
+# This plugin provides an ssh implementation comforming to the 'console'
+# specification.  consoleserver or shellserver would be equally likely
+# to use this.
+
+import confluent.interface.console as conapi
+import eventlet
+paramiko = eventlet.import_patched('paramiko')
+
+
+class SshShell(conapi.Console):
+
+    def __init__(self, node, config, username='', password=''):
+        self.node = node
+        self.nodeconfig = config
+        self.username = username
+        self.password = password
+        self.inputmode = 0 # 0 = username, 1 = password...
+
+    def recvdata(self):
+        while self.connected:
+            pendingdata = self.shell.recv(8192)
+            if pendingdata == '':
+                self.datacallback(conapi.ConsoleEvent.Disconnect)
+                return
+            self.datacallback(pendingdata)
+
+    def connect(self, callback):
+        # for now, we just use the nodename as the presumptive ssh destination
+        #TODO(jjohnson2): use a 'nodeipget' utility function for architectures
+        # that would rather not use the nodename as anything but an opaque
+        # identifier
+        self.datacallback = callback
+        if self.username is not '':
+            self.logon()
+        else:
+            self.inputmode = 0
+            callback('\r\nlogin as: ')
+        return
+
+    def logon(self):
+        self.ssh = paramiko.SSHClient()
+        self.ssh.set_missing_host_key_policy(paramiko.client.AutoAddPolicy())
+        try:
+            self.ssh.connect(self.node, username=self.username,
+                             password=self.password, allow_agent=False,
+                             look_for_keys=False)
+        except paramiko.AuthenticationException:
+            self.inputmode = 0
+            self.username = ''
+            self.password = ''
+            self.datacallback('\r\nlogin as: ')
+            return
+        self.inputmode = 2
+        self.connected = True
+        self.shell = self.ssh.invoke_shell()
+        self.rxthread = eventlet.spawn(self.recvdata)
+
+    def write(self, data):
+        if self.inputmode == 0:
+            self.username += data
+            if '\r' in self.username:
+                self.username, self.password = self.username.split('\r')
+                lastdata = data.split('\r')[0]
+                if lastdata != '':
+                    self.datacallback(lastdata)
+                self.datacallback('\r\nEnter password: ')
+                self.inputmode = 1
+            else:
+                # echo back typed data
+                self.datacallback(data)
+        elif self.inputmode == 1:
+            self.password += data
+            if '\r' in self.password:
+                self.password = self.password.split('\r')[0]
+                self.datacallback('\r\n')
+                self.logon()
+        else:
+            self.shell.sendall(data)
+
+    def close(self):
+        self.ssh.close()
+
+def create(nodes, element, configmanager, inputdata):
+    if len(nodes) == 1:
+        return SshShell(nodes[0], configmanager)