Adding a paramiko fingerprint format helper

And provide unittests for them

Signed-off-by: René Nussbaumer <rn@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

lib/ssh.py

@@ -26,12 +26,25 @@
 
 import os
 import logging
+import re
 
 from ganeti import utils
 from ganeti import errors
 from ganeti import constants
 
 
+def FormatParamikoFingerprint(fingerprint):
+  """Formats the fingerprint of L{paramiko.PKey.get_fingerprint()}
+
+  @type fingerprint: str
+  @param fingerprint: PKey fingerprint
+  @return The string hex representation of the fingerprint
+
+  """
+  assert len(fingerprint) % 2 == 0
+  return ":".join(re.findall(r"..", fingerprint.lower()))
+
+
 def GetUserFiles(user, mkdir=False):
   """Return the paths of a user's ssh files.
 

test/ganeti.ssh_unittest.py

@@ -47,6 +47,12 @@ class TestKnownHosts(testutils.GanetiTestCase):
         "%s ssh-rsa %s\n" % (cfg.GetClusterName(),
                              mocks.FAKE_CLUSTER_KEY))
 
+  def testFormatParamikoFingerprintCorrect(self):
+    self.assertEqual(ssh.FormatParamikoFingerprint("C0Ffee"), "c0:ff:ee")
+
+  def testFormatParamikoFingerprintNotDividableByTwo(self):
+    self.assertRaises(AssertionError, ssh.FormatParamikoFingerprint, "C0Ffe")
+
 
 if __name__ == '__main__':
   testutils.GanetiTestProgram()