feat: Allow Python runtime to build without requiring a manifest

aws_lambda_builders/workflows/python_pip/packager.py

@@ -35,6 +35,11 @@ class InvalidSourceDistributionNameError(PackagerError):
 
 
 class RequirementsFileNotFoundError(PackagerError):
+    """
+    Exceptions is no longer raised.
+    Keeping it here because this exception is 'public' and could still be used by a customer.
+    """
+
     def __init__(self, requirements_path):
         super(RequirementsFileNotFoundError, self).__init__("Requirements file not found: %s" % requirements_path)
 
@@ -131,9 +136,6 @@ def build_dependencies(self, artifacts_dir_path, scratch_dir_path, requirements_
         # by finding/creating a virtualenv of the correct version and when
         # pip is called set the appropriate env vars.
 
-        if not self.osutils.file_exists(requirements_path):
-            raise RequirementsFileNotFoundError(requirements_path)
-
         self._dependency_builder.build_site_packages(requirements_path, artifacts_dir_path, scratch_dir_path)
 
 

aws_lambda_builders/workflows/python_pip/workflow.py

@@ -1,11 +1,16 @@
 """
 Python PIP Workflow
 """
+import logging
+
 from aws_lambda_builders.workflow import BaseWorkflow, Capability
 from aws_lambda_builders.actions import CopySourceAction
 from aws_lambda_builders.workflows.python_pip.validator import PythonRuntimeValidator
 
 from .actions import PythonPipBuildAction
+from .utils import OSUtils
+
+LOG = logging.getLogger(__name__)
 
 
 class PythonPipWorkflow(BaseWorkflow):
@@ -59,16 +64,26 @@ class PythonPipWorkflow(BaseWorkflow):
         ".idea",
     )
 
-    def __init__(self, source_dir, artifacts_dir, scratch_dir, manifest_path, runtime=None, **kwargs):
+    def __init__(self, source_dir, artifacts_dir, scratch_dir, manifest_path, runtime=None, osutils=None, **kwargs):
 
         super(PythonPipWorkflow, self).__init__(
             source_dir, artifacts_dir, scratch_dir, manifest_path, runtime=runtime, **kwargs
         )
 
-        self.actions = [
-            PythonPipBuildAction(artifacts_dir, scratch_dir, manifest_path, runtime, binaries=self.binaries),
-            CopySourceAction(source_dir, artifacts_dir, excludes=self.EXCLUDED_FILES),
-        ]
+        if osutils is None:
+            osutils = OSUtils()
+
+        if osutils.file_exists(manifest_path):
+            # If a requirements.txt exists, run pip builder before copy action.
+            self.actions = [
+                PythonPipBuildAction(artifacts_dir, scratch_dir, manifest_path, runtime, binaries=self.binaries),
+                CopySourceAction(source_dir, artifacts_dir, excludes=self.EXCLUDED_FILES),
+            ]
+        else:
+            LOG.warning("requirements.txt file not found. Continuing the build without dependencies.")
+            self.actions = [
+                CopySourceAction(source_dir, artifacts_dir, excludes=self.EXCLUDED_FILES),
+            ]
 
     def get_validators(self):
         return [PythonRuntimeValidator(runtime=self.runtime)]

tests/integration/workflows/python_pip/test_python_pip.py

@@ -3,9 +3,13 @@
 import sys
 import tempfile
 from unittest import TestCase
+import mock
 
 from aws_lambda_builders.builder import LambdaBuilder
 from aws_lambda_builders.exceptions import WorkflowFailedError
+import logging
+
+logger = logging.getLogger("aws_lambda_builders.workflows.python_pip.workflow")
 
 
 class TestPythonPipWorkflow(TestCase):
@@ -88,23 +92,18 @@ def test_must_fail_to_resolve_dependencies(self):
         ) or "Invalid requirement: u'adfasf=1.2.3'" in str(ctx.exception)
         self.assertTrue(message_in_exception)
 
-    def test_must_fail_if_requirements_not_found(self):
-
-        with self.assertRaises(WorkflowFailedError) as ctx:
+    def test_must_log_warning_if_requirements_not_found(self):
+        with mock.patch.object(logger, "warning") as mock_warning:
             self.builder.build(
                 self.source_dir,
                 self.artifacts_dir,
                 self.scratch_dir,
                 os.path.join("non", "existent", "manifest"),
                 runtime=self.runtime,
             )
-
-            self.builder.build(
-                self.source_dir,
-                self.artifacts_dir,
-                self.scratch_dir,
-                os.path.join("non", "existent", "manifest"),
-                runtime=self.runtime,
-            )
-
-        self.assertIn("Requirements file not found", str(ctx.exception))
+        expected_files = self.test_data_files
+        output_files = set(os.listdir(self.artifacts_dir))
+        self.assertEqual(expected_files, output_files)
+        mock_warning.assert_called_once_with(
+            "requirements.txt file not found. Continuing the build without dependencies."
+        )

tests/unit/workflows/python_pip/test_packager.py

@@ -113,7 +113,6 @@ def test_can_call_dependency_builder(self, osutils):
         mock_dep_builder.build_site_packages.assert_called_once_with(
             "path/to/requirements.txt", "artifacts/path/", "scratch_dir/path/"
         )
-        osutils_mock.file_exists.assert_called_once_with("path/to/requirements.txt")
 
 
 class TestPackage(object):

tests/unit/workflows/python_pip/test_workflow.py

@@ -1,19 +1,37 @@
+import mock
+
 from unittest import TestCase
 
 from aws_lambda_builders.actions import CopySourceAction
+from aws_lambda_builders.workflows.python_pip.utils import OSUtils
 from aws_lambda_builders.workflows.python_pip.validator import PythonRuntimeValidator
 from aws_lambda_builders.workflows.python_pip.workflow import PythonPipBuildAction, PythonPipWorkflow
 
 
 class TestPythonPipWorkflow(TestCase):
     def setUp(self):
-        self.workflow = PythonPipWorkflow("source", "artifacts", "scratch_dir", "manifest", runtime="python3.7")
+        self.osutils = OSUtils()
 
     def test_workflow_sets_up_actions(self):
+        osutils_mock = mock.Mock(spec=self.osutils)
+        osutils_mock.file_exists.return_value = True
+        self.workflow = PythonPipWorkflow(
+            "source", "artifacts", "scratch_dir", "manifest", runtime="python3.7", osutils=osutils_mock
+        )
         self.assertEqual(len(self.workflow.actions), 2)
         self.assertIsInstance(self.workflow.actions[0], PythonPipBuildAction)
         self.assertIsInstance(self.workflow.actions[1], CopySourceAction)
 
+    def test_workflow_sets_up_actions_without_requirements(self):
+        osutils_mock = mock.Mock(spec=self.osutils)
+        osutils_mock.file_exists.return_value = False
+        self.workflow = PythonPipWorkflow(
+            "source", "artifacts", "scratch_dir", "manifest", runtime="python3.7", osutils=osutils_mock
+        )
+        self.assertEqual(len(self.workflow.actions), 1)
+        self.assertIsInstance(self.workflow.actions[0], CopySourceAction)
+
     def test_workflow_validator(self):
+        self.workflow = PythonPipWorkflow("source", "artifacts", "scratch_dir", "manifest", runtime="python3.7")
         for validator in self.workflow.get_validators():
             self.assertTrue(isinstance(validator, PythonRuntimeValidator))