Fix usage of old ip/port when a server is restarting

- This would result in failure to start single-user server by
  requesting it to bind to the wrong IP/port.
- Closes: #76

Author: mbmilligan

README.md

@@ -141,6 +141,8 @@ clusters, as well as an option to run a local notebook directly on the jupyterhu
 
 ### v0.8.1 (bugfix release)
 
+* Fix regression: single-user server binding address is overwritten by previous session server address, resulting in failure to start.  Issue #76
+
 ### v0.8.0 (compatible with JupyterHub 0.5.0 through 0.8.1/0.9dev)
 
 * SlurmSpawner: Remove `--uid` for (at least) Slurm 17.11 compatibility.  If you use `sudo`, this should not be necessary, but because this is security related you should check that user management is as you expect.  If your configuration does not use `sudo` then you may need to add the `--uid` option in a custom `batch_script`.
@@ -158,6 +160,7 @@ clusters, as well as an option to run a local notebook directly on the jupyterhu
 * WrapSpawner and ProfilesSpawner, which provide mechanisms for runtime configuration of spawners, have been split out and moved to the [`wrapspawner`](https://github.com/jupyterhub/wrapspawner) package
 * Enable CI testing via Travis-CI
 
+
 ### v0.3 (tag: jhub-0.3, compatible with JupyterHub 0.3.0)
 
 * initial release containing `TorqueSpawner` and `SlurmSpawner`

batchspawner/batchspawner.py

@@ -155,6 +155,9 @@ def _req_keepvars_default(self):
     # Will get the raw output of the job status command unless overridden
     job_status = Unicode()
 
+    # Will get the address of the server as reported by job manager
+    current_ip = Unicode()
+
     # Prepare substitution variables for templates using req_xyz traits
     def get_req_subvars(self):
         reqlist = [ t for t in self.trait_names() if t.startswith('req_') ]
@@ -317,17 +320,17 @@ def start(self):
                 assert self.state_ispending()
             yield gen.sleep(self.startup_poll_interval)
 
-        self.ip = self.state_gethost()
+        self.current_ip = self.state_gethost()
         if jupyterhub.version_info < (0,7):
             # store on user for pre-jupyterhub-0.7:
             self.user.server.port = self.port
-            self.user.server.ip = self.ip
+            self.user.server.ip = self.current_ip
         self.db.commit()
         self.log.info("Notebook server job {0} started at {1}:{2}".format(
-                        self.job_id, self.ip, self.port)
+                        self.job_id, self.current_ip, self.port)
             )
 
-        return self.ip, self.port
+        return self.current_ip, self.port
 
     @gen.coroutine
     def stop(self, now=False):
@@ -347,7 +350,7 @@ def stop(self, now=False):
             yield gen.sleep(1.0)
         if self.job_id:
             self.log.warn("Notebook server job {0} at {1}:{2} possibly failed to terminate".format(
-                             self.job_id, self.ip, self.port)
+                             self.job_id, self.current_ip, self.port)
                 )
 
 import re

batchspawner/tests/test_spawners.py

@@ -54,7 +54,7 @@ def check_ip(spawner, value):
     if version_info < (0,7):
         assert spawner.user.server.ip == value
     else:
-        assert spawner.ip == value
+        assert spawner.current_ip == value
 
 def test_spawner_start_stop_poll(db, io_loop):
     spawner = new_spawner(db=db)