session manager restructuring

Redid the sessionmanager, added tests for the session manager,
and added a sqlite database to hold kernel,session,nb mapping.

IPython/html/services/kernels/kernelmanager.py

@@ -46,17 +46,16 @@ class MappingKernelManager(MultiKernelManager):
         self.log.warn("Kernel %s died, removing from map.", kernel_id)
         self.remove_kernel(kernel_id)
 
-    def start_kernel(self, **kwargs):
+    def start_kernel(self, kernel_id=None, **kwargs):
         """Start a kernel for a session an return its kernel_id.
 
         Parameters
         ----------
-        session_id : uuid
-            The uuid of the session to associate the new kernel with. If this
-            is not None, this kernel will be persistent whenever the session
-            requests a kernel.
+        kernel_id : uuid
+            The uuid to associate the new kernel with. If this
+            is not None, this kernel will be persistent whenever it is 
+            requested.
         """
-        kernel_id = None
         if kernel_id is None:
             kwargs['extra_arguments'] = self.kernel_argv
             kernel_id = super(MappingKernelManager, self).start_kernel(**kwargs)

IPython/html/services/sessions/handlers.py

@@ -28,7 +28,6 @@ from ...base.handlers import IPythonHandler
 #-----------------------------------------------------------------------------
 
 
-
 class SessionRootHandler(IPythonHandler):
 
     @web.authenticated
@@ -45,12 +44,19 @@ class SessionRootHandler(IPythonHandler):
         nbm = self.notebook_manager
         km = self.kernel_manager
         notebook_path = self.get_argument('notebook_path', default=None)
-        notebook_name, path = nbm.named_notebook_path(notebook_path)
-        session_id, model = sm.get_session(notebook_name, path)
-        if model == None:
-            kernel_id = km.start_kernel()
+        name, path = nbm.named_notebook_path(notebook_path)
+        if sm.session_exists(name=name, path=path):
+            model = sm.get_session(name=name, path=path)
+            kernel_id = model['kernel']['id']
+            km.start_kernel(kernel_id, cwd=nbm.notebook_dir)
+        else:
+            session_id = sm.get_session_id()
+            sm.save_session(session_id=session_id, name=name, path=path)
+            kernel_id = km.start_kernel(cwd=nbm.notebook_dir)
             kernel = km.kernel_model(kernel_id, self.ws_url)
-            model = sm.session_model(session_id, notebook_name, path, kernel)
+            sm.update_session(session_id, kernel=kernel_id)
+            model = sm.get_session(id=session_id)
+        self.set_header('Location', '{0}kernels/{1}'.format(self.base_kernel_url, kernel_id))
         self.finish(jsonapi.dumps(model))
 
 class SessionHandler(IPythonHandler):
@@ -60,20 +66,19 @@ class SessionHandler(IPythonHandler):
     @web.authenticated
     def get(self, session_id):
         sm = self.session_manager
-        model = sm.get_session_from_id(session_id)
+        model = sm.get_session(id=session_id)
         self.finish(jsonapi.dumps(model))
 
     @web.authenticated
     def patch(self, session_id):
+        # Currently, this handler is strictly for renaming notebooks
         sm = self.session_manager
         nbm = self.notebook_manager
         km = self.kernel_manager
         notebook_path = self.request.body
-        notebook_name, path = nbm.named_notebook_path(notebook_path)
-        kernel_id = sm.get_kernel_from_session(session_id)
-        kernel = km.kernel_model(kernel_id, self.ws_url)
-        sm.delete_mapping_for_session(session_id)
-        model = sm.session_model(session_id, notebook_name, path, kernel)
+        name, path = nbm.named_notebook_path(notebook_path)
+        sm.update_session(id=session_id, name=name)
+        model = sm.get_session(id=session_id)
         self.finish(jsonapi.dumps(model))
 
     @web.authenticated
@@ -81,9 +86,9 @@ class SessionHandler(IPythonHandler):
         sm = self.session_manager
         nbm = self.notebook_manager
         km = self.kernel_manager
-        kernel_id = sm.get_kernel_from_session(session_id)
-        km.shutdown_kernel(kernel_id)
-        sm.delete_mapping_for_session(session_id)
+        session = sm.get_session(id=session_id)
+        sm.delete_session(session_id)        
+        km.shutdown_kernel(session['kernel']['id'])
         self.set_status(204)
         self.finish()
 
@@ -99,6 +104,3 @@ default_handlers = [
     (r"api/sessions",  SessionRootHandler)
 ]
 
-
-
-

IPython/html/services/sessions/sessionmanager.py

@@ -18,6 +18,7 @@ Authors:
 
 import os
 import uuid
+import sqlite3
 
 from tornado import web
 
@@ -31,67 +32,139 @@ from IPython.utils.traitlets import List, Dict, Unicode, TraitError
 
 class SessionManager(LoggingConfigurable):
     
-    # Use session_ids to map notebook names to kernel_ids
-    sessions = List()
+    # Session database initialized below
+    _cursor = None
+    _connection = None
     
-    def get_session(self, nb_name, nb_path=None):
-        """Get an existing session or create a new one"""
-        model = None
-        for session in self.sessions:
-            if session['name'] == nb_name and session['path'] == nb_path:
-                session_id = session['id']
-                model = session
-        if model != None:
-            return session_id, model
+    @property
+    def cursor(self):
+        """Start a cursor and create a database called 'session'"""
+        if self._cursor is None:
+            self._cursor = self.connection.cursor()
+            self._cursor.execute("""CREATE TABLE session 
+                (id, name, path, kernel)""")
+        return self._cursor
+
+    @property
+    def connection(self):
+        """Start a database connection"""
+        if self._connection is None:
+            self._connection = sqlite3.connect(':memory:')
+            self._connection.row_factory = sqlite3.Row
+        return self._connection
+        
+    def __del__(self):
+        """Close connection once SessionManager closes"""
+        self.cursor.close()
+
+    def session_exists(self, name, path):
+        """Check to see if the session for the given notebook exists"""
+        self.cursor.execute("SELECT * FROM session WHERE name=? AND path=?", (name,path))
+        reply = self.cursor.fetchone()
+        if reply is None:
+            return False
         else:
-            session_id = unicode(uuid.uuid4())
-            return session_id, model
-    
-    def session_model(self, session_id, notebook_name=None, notebook_path=None, kernel=None):
-        """ Create a session that links notebooks with kernels """
-        model = dict(id=session_id,
-                name=notebook_name, 
-                path=notebook_path, 
-                kernel=kernel)
-        if notebook_path == None:
-            model['path']=""
-        self.sessions.append(model)
-        return model
-    
-    def list_sessions(self):
-        """List all sessions and their information"""
-        return self.sessions
-    
-    def set_kernel_for_sessions(self, session_id, kernel_id):
-        """Maps the kernel_ids to the session_id in session_mapping"""
-        for session in self.sessions:
-            if session['id'] == session_id:
-                session['kernel']['id'] = kernel_id
-        return self.sessions
+            return True
+
+    def get_session_id(self):
+        "Create a uuid for a new session"
+        return unicode(uuid.uuid4())
+
+    def save_session(self, session_id, name=None, path=None, kernel=None):
+        """ Given a session_id (and any other of the arguments), this method
+        creates a row in the sqlite session database that holds the information
+        for a session.
         
-    def delete_mapping_for_session(self, session_id):
-        """Delete the session from session_mapping with the given session_id"""
-        i = 0
-        for session in self.sessions:
-            if session['id'] == session_id:
-                del self.sessions[i]
-            i = i + 1
-        return self.sessions
+        Parameters
+        ----------
+        session_id : str
+            uuid for the session; this method must be given a session_id
+        name : str
+            the .ipynb notebook name that started the session
+        path : str
+            the path to the named notebook
+        kernel : str
+            a uuid for the kernel associated with this session
+        """
+        self.cursor.execute("""INSERT INTO session VALUES 
+            (?,?,?,?)""", (session_id, name, path, kernel))
+        self.connection.commit()
+
+    def get_session(self, **kwargs):
+        """ Takes a keyword argument and searches for the value in the session
+        database, then returns the rest of the session's info.
+
+        Parameters
+        ----------
+        **kwargs : keyword argument
+            must be given one of the keywords and values from the session database
+            (i.e. session_id, name, path, kernel)
+
+        Returns
+        -------
+        model : dict
+            returns a dictionary that includes all the information from the 
+            session described by the kwarg.
+        """
+        column = kwargs.keys()[0] # uses only the first kwarg that is entered
+        value = kwargs.values()[0]
+        try:
+            self.cursor.execute("SELECT * FROM session WHERE %s=?" %column, (value,))
+        except sqlite3.OperationalError:
+            raise TraitError("The session database has no column: %s" %column)
+        reply = self.cursor.fetchone()
+        if reply is not None:
+            model = self.reply_to_dictionary_model(reply)
+        else:
+            model = None
+        return model
+
+    def update_session(self, session_id, **kwargs):
+        """Updates the values in the session with the given session_id
+        with the values from the keyword arguments. 
         
-    def get_session_from_id(self, session_id):
-        for session in self.sessions:
-            if session['id'] == session_id:
-                return session
-
-    def get_notebook_from_session(self, session_id):
-        """Returns the notebook_path for the given session_id"""
-        for session in self.sessions:
-            if session['id'] == session_id:
-                return session['name']
-    
-    def get_kernel_from_session(self, session_id):
-        """Returns the kernel_id for the given session_id"""
-        for session in self.sessions:
-            if session['id'] == session_id:
-                return session['kernel']['id']
+        Parameters
+        ----------
+        session_id : str
+            a uuid that identifies a session in the sqlite3 database
+        **kwargs : str
+            the key must correspond to a column title in session database,
+            and the value replaces the current value in the session 
+            with session_id.
+        """
+        column = kwargs.keys()[0] # uses only the first kwarg that is entered
+        value = kwargs.values()[0]
+        try:
+            self.cursor.execute("UPDATE session SET %s=? WHERE id=?" %column, (value, session_id))
+            self.connection.commit()
+        except sqlite3.OperationalError:
+            raise TraitError("No session exists with ID: %s" %session_id)
+
+    def reply_to_dictionary_model(self, reply):
+        """Takes sqlite database session row and turns it into a dictionary"""
+        model = {'id': reply['id'],
+                'name' : reply['name'],
+                'path' : reply['path'],
+                'kernel' : {'id':reply['kernel'], 'ws_url': ''}}
+        return model
         
+    def list_sessions(self):
+        """Returns a list of dictionaries containing all the information from
+        the session database"""
+        session_list=[]
+        self.cursor.execute("SELECT * FROM session")
+        sessions = self.cursor.fetchall()
+        for session in sessions:
+            model = self.reply_to_dictionary_model(session)
+            session_list.append(model)
+        return session_list
+
+    def delete_session(self, session_id):
+        """Deletes the row in the session database with given session_id"""
+        # Check that session exists before deleting
+        model = self.get_session(id=session_id)
+        if model is None:
+            raise TraitError("The session does not exist: %s" %session_id)
+        else: 
+            self.cursor.execute("DELETE FROM session WHERE id=?", (session_id,))
+            self.connection.commit()

IPython/html/services/sessions/tests/test_sessionmanager.py

@@ -0,0 +1,86 @@
+"""Tests for the session manager."""
+
+import os
+
+from unittest import TestCase
+from tempfile import NamedTemporaryFile
+
+from IPython.utils.tempdir import TemporaryDirectory
+from IPython.utils.traitlets import TraitError
+
+from ..sessionmanager import SessionManager
+
+class TestSessionManager(TestCase):
+    
+    def test_get_session(self):
+        sm = SessionManager()
+        session_id = sm.get_session_id()
+        sm.save_session(session_id=session_id, name='test.ipynb', path='/path/to/', kernel='5678')
+        model = sm.get_session(id=session_id)
+        expected = {'id':session_id, 'name':u'test.ipynb', 'path': u'/path/to/', 'kernel':{'id':u'5678', 'ws_url': u''}}
+        self.assertEqual(model, expected)
+
+    def test_bad_get_session(self):
+        # Should raise error if a bad key is passed to the database.
+        sm = SessionManager()
+        session_id = sm.get_session_id()
+        sm.save_session(session_id=session_id, name='test.ipynb', path='/path/to/', kernel='5678')
+        self.assertRaises(TraitError, sm.get_session, bad_id=session_id) # Bad keyword
+
+    def test_list_sessions(self):
+        sm = SessionManager()
+        session_id1 = sm.get_session_id()
+        session_id2 = sm.get_session_id()
+        session_id3 = sm.get_session_id()
+        sm.save_session(session_id=session_id1, name='test1.ipynb', path='/path/to/1/', kernel='5678')
+        sm.save_session(session_id=session_id2, name='test2.ipynb', path='/path/to/2/', kernel='5678')
+        sm.save_session(session_id=session_id3, name='test3.ipynb', path='/path/to/3/', kernel='5678')
+        sessions = sm.list_sessions()
+        expected = [{'id':session_id1, 'name':u'test1.ipynb', 
+                    'path': u'/path/to/1/', 'kernel':{'id':u'5678', 'ws_url': u''}},
+                    {'id':session_id2, 'name':u'test2.ipynb', 
+                    'path': u'/path/to/2/', 'kernel':{'id':u'5678', 'ws_url': u''}},
+                    {'id':session_id3, 'name':u'test3.ipynb', 
+                    'path': u'/path/to/3/', 'kernel':{'id':u'5678', 'ws_url': u''}}]
+        self.assertEqual(sessions, expected)
+
+    def test_update_session(self):
+        sm = SessionManager()
+        session_id = sm.get_session_id()
+        sm.save_session(session_id=session_id, name='test.ipynb', path='/path/to/', kernel=None)
+        sm.update_session(session_id, kernel='5678')
+        sm.update_session(session_id, name='new_name.ipynb')
+        model = sm.get_session(id=session_id)
+        expected = {'id':session_id, 'name':u'new_name.ipynb', 'path': u'/path/to/', 'kernel':{'id':u'5678', 'ws_url': u''}}
+        self.assertEqual(model, expected)
+    
+    def test_bad_update_session(self):
+        # try to update a session with a bad keyword ~ raise error
+        sm = SessionManager()
+        session_id = sm.get_session_id()
+        sm.save_session(session_id=session_id, name='test.ipynb', path='/path/to/', kernel='5678')
+        self.assertRaises(TraitError, sm.update_session, session_id=session_id, bad_kw='test.ipynb') # Bad keyword
+
+    def test_delete_session(self):
+        sm = SessionManager()
+        session_id1 = sm.get_session_id()
+        session_id2 = sm.get_session_id()
+        session_id3 = sm.get_session_id()
+        sm.save_session(session_id=session_id1, name='test1.ipynb', path='/path/to/1/', kernel='5678')
+        sm.save_session(session_id=session_id2, name='test2.ipynb', path='/path/to/2/', kernel='5678')
+        sm.save_session(session_id=session_id3, name='test3.ipynb', path='/path/to/3/', kernel='5678')
+        sm.delete_session(session_id2)
+        sessions = sm.list_sessions()
+        expected = [{'id':session_id1, 'name':u'test1.ipynb', 
+                    'path': u'/path/to/1/', 'kernel':{'id':u'5678', 'ws_url': u''}},
+                    {'id':session_id3, 'name':u'test3.ipynb', 
+                    'path': u'/path/to/3/', 'kernel':{'id':u'5678', 'ws_url': u''}}]
+        self.assertEqual(sessions, expected)
+
+    def test_bad_delete_session(self):
+        # try to delete a session that doesn't exist ~ raise error
+        sm = SessionManager()
+        session_id = sm.get_session_id()
+        sm.save_session(session_id=session_id, name='test.ipynb', path='/path/to/', kernel='5678')
+        self.assertRaises(TraitError, sm.delete_session, session_id='23424') # Bad keyword
+

IPython/html/static/services/kernels/js/kernel.js

@@ -24,16 +24,15 @@ var IPython = (function (IPython) {
      * A Kernel Class to communicate with the Python kernel
      * @Class Kernel
      */
-    var Kernel = function (base_url, session_id) {
+    var Kernel = function (base_url) {
         this.kernel_id = null;
-        this.session_id = session_id
         this.shell_channel = null;
         this.iopub_channel = null;
         this.stdin_channel = null;
         this.base_url = base_url;
         this.running = false;
-        this.username = "username";
-        this.base_session_id = utils.uuid();
+        this.username= "username";
+        this.session_id = utils.uuid();
         this._msg_callbacks = {};
 
         if (typeof(WebSocket) !== 'undefined') {
@@ -52,7 +51,7 @@ var IPython = (function (IPython) {
             header : {
                 msg_id : utils.uuid(),
                 username : this.username,
-                session : this.base_session_id,
+                session : this.session_id,
                 msg_type : msg_type
             },
             metadata : {},
@@ -76,7 +75,6 @@ var IPython = (function (IPython) {
      Kernel.prototype.start = function (params) {
          var that = this;
          params = params || {};
-         params.session = this.session_id;
          if (!this.running) {
              var qs = $.param(params);
              var url = this.base_url + '?' + qs;

IPython/html/static/services/sessions/js/session.js

@@ -66,7 +66,6 @@ var IPython = (function (IPython) {
         this.kernel_content = json.kernel;
         var base_url = $('body').data('baseKernelUrl') + "api/kernels";
         this.kernel = new IPython.Kernel(base_url, this.session_id);
-        // Now that the kernel has been created, tell the CodeCells about it.
         this.kernel._kernel_started(this.kernel_content);
     };