Add step decorator usage (#1)

* Add .python-version to .gitignore

* Make step function usable as a decorator with warning

* Update pipeline step error message

* Update tests

* Update README

.gitignore

@@ -6,4 +6,6 @@ __pycache__/
 *.DS_Store
 *.egg-info
 
-*.env
+*.env
+
+.python-version

README.md

@@ -14,7 +14,7 @@ $ pip install tinypipeline
 
 `tinypipeline` exposes two main objects:
 - `pipeline`: a decorator for defining your pipeline. Returns a `Pipeline` instance.
-- `step`: a function that is used to define individual pipeline steps. Returns a `Step` instance.
+- `step`: a decorator that is used to define individual pipeline steps. Returns a `Step` instance.
 
 Each object requires you provide a `name`, `version`, and `description` to explicitly define what pipeline you're creating.
 
@@ -27,11 +27,12 @@ If you'd like to use this package, you can follow the `example.py` below:
 ```python
 from tinypipeline import pipeline, step
 
-
-def step_fn_one():
+@step(name='step_one', version='0.0.1', description='first step')
+def step_one():
     print("Step function one")
 
-def step_fn_two():
+@step(name='step_two', version='0.0.1', description='second step')
+def step_two():
     print("Step function two")
 
 @pipeline(
@@ -40,18 +41,6 @@ def step_fn_two():
     description='a test tinypipeline',
 )
 def pipe():
-    step_one = step(
-        callable=step_fn_one, 
-        name='step_one', 
-        version='0.0.1', 
-        description='first step',
-    )
-    step_two = step(
-        name='step_two',
-        version='0.0.1',
-        description='second step',
-        callable=step_fn_two,
-    )
     return [step_one, step_two]
 
 pipe = pipe()

tests/test_pipeline.py

@@ -54,6 +54,58 @@ def test_pipeline():
     mock_step_2.assert_called_once()
     mock_step_3.assert_called_once()
 
+def test_pipeline_completion_using_step_decorator():
+    """
+    Test that the pipeline runs all the steps in the correct order,
+    using the step decorator instead of the step function.
+    """
+    mock_step_1 = Mock()
+    mock_step_2 = Mock()
+    mock_step_3 = Mock()
+
+    mock_step_1.return_value = "step 1"
+    mock_step_2.return_value = "step 2"
+    mock_step_3.return_value = "step 3"
+
+    @step(
+        name="step_one",
+        description="Step one",
+        version="1.0.0",
+    )
+    def step_one():
+        mock_step_1()
+
+    @step(
+        name="step_two",
+        description="Step two",
+        version="1.0.0",
+    )
+    def step_two():
+        mock_step_2()
+
+    @step(
+        name="step_three",
+        description="Step three",
+        version="1.0.0",
+    )
+    def step_three():
+        mock_step_3()
+
+    @pipeline(
+        name="test_pipeline",
+        description="Test pipeline",
+        version="1.0.0",
+    )
+    def test_pipeline():
+        return [step_one, step_two, step_three]
+
+    pipe = test_pipeline()
+    pipe.run()
+
+    assert len(pipe.steps) == 3
+    mock_step_1.assert_called_once()
+    mock_step_2.assert_called_once()
+    mock_step_3.assert_called_once() 
 
 def test_pipeline_failure_no_function_passed():
     """
@@ -97,7 +149,8 @@ def test_pipeline():
         pipe.run()
 
     assert (
-        "Not a valid step. Consider using the step() method to create steps for your pipeline."
+        "Not a valid step. Consider using the step decorator to "
+        "create steps for your pipeline."
         == str(context.value)
     )
 
@@ -145,7 +198,8 @@ def test_pipeline():
 
 def test_pipeline_failure_exception_in_step():
     """
-    Test that the pipeline fails with an Exception if there is an exception in one of the steps.
+    Test that the pipeline fails with an Exception if there is an exception
+    in one of the steps.
 
     Also check that the error message is correct.
     """

tinypipeline/pipeline.py

@@ -55,7 +55,8 @@ def _get_steps(self):
 
         if not all(isinstance(s, Step) for s in _steps):
             raise TypeError(
-                "Not a valid step. Consider using the step() method to create steps for your pipeline."
+                "Not a valid step. Consider using the step decorator "
+                "to create steps for your pipeline."
             )
 
         return _steps
@@ -86,7 +87,7 @@ def run(self) -> None:
 
                 completion_time = (end - start).total_seconds()
                 print(f"Step [{step.name}] completed in {completion_time} seconds\n")
-            except Exception as e:
+            except Exception:
                 print(f"Pipeline failed due to an exception in step [{step.name}]")
                 raise
         return None
@@ -119,7 +120,8 @@ def wrapper():
             """
             if not isinstance(func, Callable):
                 raise TypeError(
-                    f"The pipeline decorator only accepts functions. Passed {type(func)}"
+                    "The pipeline decorator only accepts functions. "
+                    f"Passed {type(func)}"
                 )
 
             _pipeline = Pipeline(

tinypipeline/step.py

@@ -37,13 +37,13 @@ def run(self):
 
 
 def step(
-    callable: Callable,
     name: str,
     version: str,
     description: str,
+    callable: Callable = None,
 ):
     """
-    Create a step for a pipeline.
+    Create a step for a pipeline. Can be used as a decorator or a function.
 
     Params
     ------
@@ -56,10 +56,27 @@ def step(
     description: str
         A description of the step.
     """
-    _step = Step(
-        callable=callable,
-        name=name,
-        version=version,
-        description=description,
-    )
-    return _step
+    if callable is not None:
+        print(
+            f"WARNING: step() is being used as a function for {name}. "
+            "This is deprecated and will be removed in a future version. "
+            "Please use step() as a decorator instead."
+        )
+
+        _step = Step(
+            callable=callable,
+            name=name,
+            version=version,
+            description=description,
+        )
+        return _step
+
+    def decorator(callable):
+        _step = Step(
+            callable=callable,
+            name=name,
+            version=version,
+            description=description,
+        )
+        return _step
+    return decorator