feat: Add initial RUN level validation

Author: Alan Christie

workflow/workflow_validator.py

@@ -1,5 +1,6 @@
 """The WorkflowEngine validation logic."""
 
+import json
 from dataclasses import dataclass
 from enum import Enum
 from typing import Any
@@ -47,7 +48,59 @@ def validate(
         if workflow_inputs:
             assert isinstance(workflow_inputs, dict)
 
+        # ALl levels require a schema validation
         if error := validate_schema(workflow_definition):
             return ValidationResult(error_num=1, error_msg=[error])
 
+        if level == ValidationLevel.RUN:
+            run_level_result: ValidationResult = WorkflowValidator._validate_run_level(
+                workflow_definition=workflow_definition,
+                workflow_inputs=workflow_inputs,
+            )
+            if run_level_result.error_num:
+                return run_level_result
+
+        return _VALIDATION_SUCCESS
+
+    @classmethod
+    def _validate_run_level(
+        cls,
+        *,
+        workflow_definition: dict[str, Any],
+        workflow_inputs: dict[str, Any] | None = None,
+    ) -> ValidationResult:
+        assert workflow_definition
+        del workflow_inputs
+
+        # RUN level requires that the specification is a valid JSON string.
+        # and contains properties for 'collection', 'job', and 'version'.
+        try:
+            specification = json.loads(workflow_definition["specification"])
+        except json.decoder.JSONDecodeError as e:
+            return ValidationResult(
+                error_num=1,
+                error_msg=[
+                    f"Error decoding specification, which is not valid JSON: {e}"
+                ],
+            )
+        except TypeError as e:
+            return ValidationResult(
+                error_num=2,
+                error_msg=[
+                    f"Error decoding specification, which is not valid JSON: {e}"
+                ],
+            )
+        expected_keys: set[str] = {"collection", "job", "version"}
+        missing_keys: list[str] = []
+        missing_keys.extend(
+            expected_key
+            for expected_key in expected_keys
+            if expected_key not in specification
+        )
+        if missing_keys:
+            return ValidationResult(
+                error_num=2,
+                error_msg=[f"Specification is missing: {', '.join(missing_keys)}"],
+            )
+
         return _VALIDATION_SUCCESS