Fix the manhole for Twisted > 16 and Python 3

This probably breaks the manhole for Python 2 and old versions of
Twisted.

Author: piotr1212

conf/carbon.conf.example

@@ -294,11 +294,18 @@ WHISPER_FALLOCATE_CREATE = True
 # you are familiar with the code. If you are not, please don't
 # mess with this, you are asking for trouble :)
 #
+# You need the bcrypt, cryptography and pyasn1 python modules installed for
+# manhole to work.
+#
+# Generate host keys with:
+# `ckeygen -t rsa -f /example/host_keys/ssh_host_key_rsa`
+#
 # ENABLE_MANHOLE = False
 # MANHOLE_INTERFACE = 127.0.0.1
 # MANHOLE_PORT = 7222
 # MANHOLE_USER = admin
 # MANHOLE_PUBLIC_KEY = ssh-rsa AAAAB3NzaC1yc2EAAAABiwAaAIEAoxN0sv/e4eZCPpi3N3KYvyzRaBaMeS2RsOQ/cDuKv11dlNzVeiyc3RFmCv5Rjwn/lQ79y0zyHxw67qLyhQ/kDzINc4cY41ivuQXm2tPmgvexdrBv5nsfEpjs3gLZfJnyvlcVyWK/lId8WUvEWSWHTzsbtmXAF2raJMdgLTbQ8wE=
+# MANHOLE_HOST_KEY_DIR = /example/host_keys
 
 # Patterns for all of the metrics this machine will store. Read more at
 # http://en.wikipedia.org/wiki/Advanced_Message_Queuing_Protocol#Bindings

lib/carbon/conf.py

@@ -88,6 +88,7 @@
   MANHOLE_PORT=7222,
   MANHOLE_USER="",
   MANHOLE_PUBLIC_KEY="",
+  MANHOLE_HOST_KEY_DIR="",
   RELAY_METHOD='rules',
   DYNAMIC_ROUTER=False,
   DYNAMIC_ROUTER_MAX_RETRIES=5,

lib/carbon/manhole.py

@@ -3,14 +3,17 @@
 from twisted.conch.checkers import SSHPublicKeyDatabase
 from twisted.conch.manhole import Manhole
 from twisted.conch.manhole_ssh import TerminalRealm, ConchFactory
+from twisted.conch.openssh_compat.factory import OpenSSHFactory
 from twisted.internet import reactor
 from twisted.application.internet import TCPServer
 
 from carbon.protocols import CarbonServerProtocol
 from carbon.conf import settings
+import carbon
 
+from carbon.exceptions import CarbonConfigException
 
-namespace = {}
+namespace = {'carbon': carbon}
 
 
 class PublicKeyChecker(SSHPublicKeyDatabase):
@@ -31,16 +34,27 @@ def createManholeListener():
 
   if settings.MANHOLE_PUBLIC_KEY == 'None':
     credChecker = checkers.InMemoryUsernamePasswordDatabaseDontUse()
-    credChecker.addUser(settings.MANHOLE_USER, '')
+    credChecker.addUser(settings.MANHOLE_USER.encode('utf-8'),
+                        ''.encode('utf-8'))
   else:
     userKeys = {
-        settings.MANHOLE_USER: settings.MANHOLE_PUBLIC_KEY,
+        settings.MANHOLE_USER.encode('utf-8'):
+            settings.MANHOLE_PUBLIC_KEY.encode('utf-8'),
     }
     credChecker = PublicKeyChecker(userKeys)
 
   sshPortal = portal.Portal(sshRealm)
   sshPortal.registerChecker(credChecker)
   sessionFactory = ConchFactory(sshPortal)
+
+  # set ssh host keys
+  if settings.MANHOLE_HOST_KEY_DIR == "":
+    raise CarbonConfigException("MANHOLE_HOST_KEY_DIR not defined")
+  openSSHFactory = OpenSSHFactory()
+  openSSHFactory.dataRoot = settings.MANHOLE_HOST_KEY_DIR
+  sessionFactory.publicKeys = openSSHFactory.getPublicKeys()
+  sessionFactory.privateKeys = openSSHFactory.getPrivateKeys()
+
   return sessionFactory