Add execution timings in code cell metadata for v4 spec

nbformat/tests/test4jupyter_metadata_timings.ipynb

@@ -0,0 +1,61 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "execution": {
+     "iopub.execute_input": "2019-08-26T17:50:29.604738Z",
+     "iopub.status.busy": "2019-08-26T17:50:29.603423Z",
+     "iopub.status.idle": "2019-08-26T17:50:29.628032Z",
+     "shell.execute_reply": "2019-08-26T17:50:29.623438Z",
+     "shell.execute_reply.started": "2019-08-26T17:50:29.604616Z"
+    }
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "2"
+      ]
+     },
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "1+1"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.0"
+  },
+  "record_timing": true
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

nbformat/tests/test_validator.py

@@ -55,6 +55,13 @@ def test_nb4jupyter_metadata(self):
         validate(nb)
         self.assertEqual(isvalid(nb), True)
 
+    def test_nb4jupyter_metadata_timings(self):
+        """Tests that a notebook with "timing" in metadata passes validation"""
+        with self.fopen(u'test4jupyter_metadata_timings.ipynb', u'r') as f:
+            nb = read(f, as_version=4)
+        validate(nb)
+        self.assertTrue(isvalid(nb))
+
     def test_invalid(self):
         """Test than an invalid notebook does not pass validation"""
         # this notebook has a few different errors:

nbformat/v4/nbformat.v4.schema.json

@@ -205,6 +205,34 @@
                                 "type": "boolean"
                             }
                         },
+                        "execution": {
+                            "description": "Execution time for the code in the cell. This tracks time at which messages are recieved from iopub or shell channels",
+                            "type": "object",
+                            "properties": {
+                                "iopub.execute_input": {
+                                    "description": "header.date (in ISO 8601 format) of iopub channel's execute_input message. It indicates the time at which the kernel broadcast an execute_input message to connected frontends",
+                                    "type": "string"
+                                },
+                                "iopub.status.busy": {
+                                    "description": "header.date (in ISO 8601 format) of iopub channel's kernel status message when the status is 'busy'",
+                                    "type": "string"
+                                },
+                                "shell.execute_reply": {
+                                    "description": "header.date (in ISO 8601 format) of the shell channel's execute_reply message. It indicates the time at which the execute_reply message was created",
+                                    "type": "string"
+                                },
+                                "iopub.status.idle": {
+                                    "description": "header.date (in ISO 8601 format) of iopub channel's execute_input message. It indicates the time at which kernel finished processing the associated request",
+                                    "type": "string"
+                                }
+                            },
+                            "additionalProperties": true,
+                            "patternProperties": {
+                                "^.*$": {
+                                    "type": "string"
+                                }
+                            }
+                        },
                         "collapsed": {
                             "description": "Whether the cell's output is collapsed/expanded.",
                             "type": "boolean"