Merge pull request #19 from ddelange/timestamp

Add 'started' timestamp to output (with local timezone)

README.md

@@ -11,10 +11,10 @@ $ pip install ipython-autotime
 
 ```python
 In [1]: %load_ext autotime
-time: 295 µs
+time: 264 µs (started: 2020-12-15 11:44:36 +01:00)
 
 In [2]: x = 1
-time: 519 µs
+time: 416 µs (started: 2020-12-15 11:44:45 +01:00)
 
 In [3]: x / 0
 ---------------------------------------------------------------------------
@@ -23,7 +23,7 @@ ZeroDivisionError                         Traceback (most recent call last)
 ----> 1 x/0
 
 ZeroDivisionError: division by zero
-time: 79.7 ms
+time: 88.7 ms (started: 2020-12-15 11:44:53 +01:00)
 ```
 
 ## Want to turn it off?

autotime/__init__.py

@@ -2,6 +2,8 @@
 
 from ._version import version as __version__
 
+from time import strftime, localtime
+
 try:
     from time import monotonic
 except ImportError:
@@ -10,21 +12,33 @@
 from IPython.core.magics.execution import _format_time as format_delta
 
 
+def format_timestamp(struct_time):
+    timestamp = strftime('%Y-%m-%d %H:%M:%S %z', struct_time)
+    # add colon in %z (for datetime.fromisoformat, stackoverflow.com/q/44836581)
+    return '{}:{}'.format(timestamp[:-2], timestamp[-2:])
+
+
 class LineWatcher(object):
     """Class that implements a basic timer.
 
     Notes
     -----
     * Register the `start` and `stop` methods with the IPython events API.
     """
-    __slots__ = ['start_time']
+    __slots__ = ['start_time', 'timestamp']
 
     def start(self):
+        self.timestamp = localtime()
         self.start_time = monotonic()
 
     def stop(self):
         delta = monotonic() - self.start_time
-        print(u'time: {}'.format(format_delta(delta)))
+        print(
+            u'time: {} (started: {})'.format(
+                format_delta(delta),
+                format_timestamp(self.timestamp),
+            )
+        )
 
 
 timer = LineWatcher()

tests/test_autotime.py

@@ -10,7 +10,7 @@ def test_full_cycle():
     with tt.AssertPrints('time: '):
         ip.run_cell('%load_ext autotime')
 
-    with tt.AssertPrints('time: '):
+    with tt.AssertPrints(' (started: '):
         ip.run_cell('x = 1')
 
     with tt.AssertNotPrints('time: '):