API: Allow NotebookManagers to control kernel startup dir. #5468

IPython/html/services/kernels/kernelmanager.py

@@ -63,6 +63,10 b' class MappingKernelManager(MultiKernelManager):'
     
     def cwd_for_path(self, path):
         """Turn API path into absolute OS path."""
+        # short circuit for NotebookManagers that pass in absolute paths
+        if os.path.exists(path):
+            return path
+
         os_path = to_os_path(path, self.root_dir)
         # in the case of notebooks and kernels not being on the same filesystem,
         # walk up to root_dir if the paths don't exist

IPython/html/services/notebooks/filenbmanager.py

@@ -492,3 +492,7 b' class FileNotebookManager(NotebookManager):'
     
     def info_string(self):
         return "Serving notebooks from local directory: %s" % self.notebook_dir
+
+    def get_kernel_path(self, name, path='', model=None):
+        """ Return the path to start kernel in """
+        return os.path.join(self.notebook_dir, path)

IPython/html/services/notebooks/nbmanager.py

@@ -168,6 +168,10 b' class NotebookManager(LoggingConfigurable):'
     # NotebookManager API part 2: methods that have useable default
     # implementations, but can be overridden in subclasses.
 
+    def get_kernel_path(self, name, path='', model=None):
+        """ Return the path to start kernel in """
+        return path
+
     def increment_filename(self, basename, path=''):
         """Increment a notebook filename without the .ipynb to make it unique.
         

IPython/html/services/sessions/handlers.py

@@ -62,7 +62,9 b' class SessionRootHandler(IPythonHandler):'
         if sm.session_exists(name=name, path=path):
             model = sm.get_session(name=name, path=path)
         else:
-            kernel_id = km.start_kernel(path=path)
+            # allow nbm to specify kernels cwd
+            kernel_path = nbm.get_kernel_path(name=name, path=path)
+            kernel_id = km.start_kernel(path=kernel_path)
             model = sm.create_session(name=name, path=path, kernel_id=kernel_id)
         location = url_path_join(self.base_url, 'api', 'sessions', model['id'])
         self.set_header('Location', url_escape(location))