batchspawner/CondorSpawner: Make use of connect_to_job feature.

This leverages condor_ssh_to_job to forward the port of the
single user server to the hub, removing the need for direct
connectivity from the hub to the execute nodes.

Author: olifre

batchspawner/batchspawner.py

@@ -886,6 +886,7 @@ class CondorSpawner(UserEnvMixin,BatchSpawnerRegexStates):
     # outputs job data XML string
     batch_query_cmd = Unicode('condor_q {job_id} -format "%s, " JobStatus -format "%s" RemoteHost -format "\n" True').tag(config=True)
     batch_cancel_cmd = Unicode('condor_rm {job_id}').tag(config=True)
+    connect_to_job_cmd = Unicode("condor_ssh_to_job -ssh \"ssh -L {port}:localhost:{port} -oExitOnForwardFailure=yes\" {job_id}").tag(config=True)
     # job status: 1 = pending, 2 = running
     state_pending_re = Unicode(r'^1,').tag(config=True)
     state_running_re = Unicode(r'^2,').tag(config=True)
@@ -903,6 +904,9 @@ def parse_job_id(self, output):
     def cmd_formatted_for_batch(self):
         return super(CondorSpawner,self).cmd_formatted_for_batch().replace('"','""').replace("'","''")
 
+    def state_gethost(self):
+        """This always returns localhost since connect_to_job forwards the singleuser server port from the spawned job"""
+        return "localhost"
 
 class LsfSpawner(BatchSpawnerBase):
     '''A Spawner that uses IBM's Platform Load Sharing Facility (LSF) to launch notebooks.'''