enforce unique application step names (#105)

foodx_devops_tools/pipeline_config/frames.py

@@ -71,6 +71,27 @@ class ApplicationDefinition(pydantic.BaseModel):
     depends_on: typing.Optional[DependencyDeclarations]
     steps: ApplicationDeploymentSteps
 
+    @pydantic.validator("steps")
+    def check_applications(
+        cls: pydantic.BaseModel, steps_candidate: ApplicationDeploymentSteps
+    ) -> ApplicationDeploymentSteps:
+        """Validate ``steps`` field."""
+        step_names: typing.List[str] = [
+            x.name
+            for x in steps_candidate
+            if not isinstance(x, ApplicationStepDelay)
+        ]
+        if len(step_names) != len(set(step_names)):
+            message = "Application step names must be unique, {0}".format(
+                str(step_names)
+            )
+            # log the message here because pydantic exception handling
+            # masks the true exception that caused a validation failure.
+            log.error(message)
+            raise ValueError(message)
+
+        return steps_candidate
+
 
 ApplicationDeclarations = typing.Dict[str, ApplicationDefinition]
 

tests/ci/unit_tests/pipeline_config/test_frames.py

@@ -458,6 +458,31 @@ def test_bad_dependency_raises(apply_applications_test):
         apply_applications_test(file_text)
 
 
+def test_duplicate_step_names_raises(apply_applications_test):
+    file_text = """---
+frames:
+  frames:
+    f1:
+      applications:
+        a1:
+          steps:
+            - arm_file: something.json
+              mode: Incremental
+              name: same_name
+              resource_group: a1_group
+            - arm_file: something_else.json
+              mode: Incremental
+              name: same_name
+              resource_group: other_group
+      folder: some/f2-path
+"""
+
+    with pytest.raises(
+        FrameDefinitionsError, match=r"Application step names must be unique"
+    ):
+        apply_applications_test(file_text)
+
+
 def test_missing_name_raises(apply_applications_test):
     file_text = """---
 frames: