Option for not writing an output ipynb file

papermill/execute.py

@@ -36,8 +36,8 @@ def execute_notebook(
     ----------
     input_path : str or Path
         Path to input notebook
-    output_path : str or Path
-        Path to save executed notebook
+    output_path : str or Path or None
+        Path to save executed notebook. If None, no file will be saved
     parameters : dict, optional
         Arbitrary keyword arguments to pass to the notebook parameters
     engine_name : str, optional

papermill/iorw.py

@@ -116,6 +116,8 @@ def read(self, path, extensions=['.ipynb', '.json']):
         return notebook_metadata
 
     def write(self, buf, path, extensions=['.ipynb', '.json']):
+        if path is None:
+            return
         if path == '-':
             try:
                 return sys.stdout.buffer.write(buf.encode('utf-8'))
@@ -158,6 +160,9 @@ def register_entry_points(self):
             self.register(entrypoint.name, entrypoint.load())
 
     def get_handler(self, path):
+        if path is None:
+            return NoIOHandler()
+
         local_handler = None
         for scheme, handler in self._handlers:
             if scheme == 'local':
@@ -406,6 +411,22 @@ def pretty_path(self, path):
         return path
 
 
+class NoIOHandler(object):
+    '''Handler for output_path of None - intended to not write anything'''
+
+    def read(self, path):
+        raise PapermillException('read is not supported by NoIOHandler')
+
+    def listdir(self, path):
+        raise PapermillException('listdir is not supported by NoIOHandler')
+
+    def write(self, buf, path):
+        return
+
+    def pretty_path(self, path):
+        return 'Notebook will not be saved'
+
+
 # Hack to make YAML loader not auto-convert datetimes
 # https://stackoverflow.com/a/52312810
 class NoDatesSafeLoader(yaml.SafeLoader):

papermill/parameterize.py

@@ -38,11 +38,14 @@ def parameterize_path(path, parameters):
 
     Parameters
     ----------
-    path : string
+    path : string or None
        Path with optional parameters, as a python format string
-    parameters : dict
+    parameters : dict or None
        Arbitrary keyword arguments to fill in the path
     """
+    if path is None:
+        return
+
     if parameters is None:
         parameters = {}
 

papermill/tests/test_execute.py

@@ -230,6 +230,13 @@ def test_report_mode(self):
                 self.assertEqual(cell.metadata.get('jupyter', {}).get('source_hidden'), True)
 
 
+class TestOutputPathNone(unittest.TestCase):
+    def test_output_path_of_none(self):
+        """Output path of None should return notebook node obj but not write an ipynb"""
+        nb = execute_notebook(get_notebook_path('simple_execute.ipynb'), None, {'msg': 'Hello'})
+        self.assertEqual(nb.metadata.papermill.parameters, {'msg': 'Hello'})
+
+
 class TestCWD(unittest.TestCase):
     def setUp(self):
         self.test_dir = tempfile.mkdtemp()

papermill/tests/test_iorw.py

@@ -15,6 +15,7 @@
 from ..iorw import (
     HttpHandler,
     LocalHandler,
+    NoIOHandler,
     ADLHandler,
     PapermillIO,
     read_yaml_file,
@@ -90,6 +91,9 @@ def test_get_local_handler(self):
         self.papermill_io.register("local", self.fake2)
         self.assertEqual(self.papermill_io.get_handler("dne"), self.fake2)
 
+    def test_get_no_io_handler(self):
+        self.assertIsInstance(self.papermill_io.get_handler(None), NoIOHandler)
+
     def test_entrypoint_register(self):
 
         fake_entrypoint = Mock(load=Mock())
@@ -163,6 +167,9 @@ def test_write_with_no_file_extension(self):
         with pytest.warns(UserWarning):
             self.papermill_io.write("buffer", "fake/path")
 
+    def test_write_with_path_of_none(self):
+        self.assertIsNone(self.papermill_io.write('buffer', None))
+
     def test_write_with_invalid_file_extension(self):
         with pytest.warns(UserWarning):
             self.papermill_io.write("buffer", "fake/path/fakeoutputpath.ipynb1")
@@ -246,6 +253,23 @@ def test_invalid_string(self):
             LocalHandler().read("a random string")
 
 
+class TestNoIOHandler(unittest.TestCase):
+    def test_raises_on_read(self):
+        with self.assertRaises(PapermillException):
+            NoIOHandler().read(None)
+
+    def test_raises_on_listdir(self):
+        with self.assertRaises(PapermillException):
+            NoIOHandler().listdir(None)
+
+    def test_write_returns_none(self):
+        self.assertIsNone(NoIOHandler().write('buf', None))
+
+    def test_pretty_path(self):
+        expect = 'Notebook will not be saved'
+        self.assertEqual(NoIOHandler().pretty_path(None), expect)
+
+
 class TestADLHandler(unittest.TestCase):
     """
     Tests for `ADLHandler`

papermill/tests/test_parameterize.py

@@ -166,3 +166,7 @@ def test_parameterized_path_with_none_parameters(self):
         with self.assertRaises(PapermillMissingParameterException) as context:
             parameterize_path("{foo}", None)
         self.assertEqual(str(context.exception), "Missing parameter 'foo'")
+
+    def test_path_of_none_returns_none(self):
+        self.assertIsNone(parameterize_path(path=None, parameters={'foo': 'bar'}))
+        self.assertIsNone(parameterize_path(path=None, parameters=None))