feat: Basic files for validator

Author: Alan Christie

pyproject.toml

@@ -29,3 +29,8 @@ build-backend = "poetry.core.masonry.api"
 omit = [
     "tests/*",
 ]
+
+[tool.pylint]
+disable = [
+    "too-few-public-methods",
+]

workflow/workflow_abc.py

@@ -0,0 +1,53 @@
+"""Workflow abstract base classes.
+Interface definitions of class instances that must be provided to the Engine.
+"""
+
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
+from typing import Any, Dict, Optional
+
+
+@dataclass
+class LaunchResult:
+    """Results returned from methods in the InstanceLauncher."""
+
+    error: int
+    error_msg: Optional[str]
+    instance_id: Optional[str]
+    task_id: Optional[str]
+
+
+class DatabaseAdapter(ABC):
+    """The DatabaseAdapter will not need to provide a save/commit service.
+    Instead it should be assumed that new database records are the
+    responsibility of the governing application code. The WE simply has
+    to implement engine logic and launch instance. The InstanceLauncher
+    is responsible for creating RunningWorkflow and RunningWorkflowStep
+    records for example."""
+
+    @abstractmethod
+    def get_workflow(
+        self,
+        *,
+        workflow_definition_id: str,
+    ) -> Optional[Dict[str, Any]]:
+        """Get a Workflow by ID"""
+
+    @abstractmethod
+    def get_workflow_by_name(
+        self,
+        *,
+        name: str,
+        version: str,
+    ) -> Optional[Dict[str, Any]]:
+        """Get a Workflow by name"""
+
+    @abstractmethod
+    def get_job(
+        self,
+        *,
+        collection: str,
+        job: str,
+        version: str,
+    ) -> Optional[Dict[str, Any]]:
+        """Get a Job"""

workflow/worklfow_validator.py

@@ -0,0 +1,63 @@
+"""The WorkflowEngine validation logic.
+"""
+
+from dataclasses import dataclass
+from enum import Enum
+from typing import Any, Dict, List, Optional
+
+from .decoder import validate_schema
+from .workflow_abc import DatabaseAdapter
+
+
+class ValidationLevel(Enum):
+    """Workflow validation levels."""
+
+    CREATE = 1
+    RUN = 2
+    TAG = 3
+
+
+@dataclass
+class ValidationResult:
+    """Workflow validation results."""
+
+    error: int
+    error_msg: Optional[List[str]]
+
+
+# A successful validation result.
+_VALIDATION_SUCCESS = ValidationResult(error=0, error_msg=None)
+
+
+class WorkflowValidator:
+    """The workflow validator. Typically used from teh context of the API
+    to check workflow content prior to creation and execution.
+    """
+
+    def __init__(
+        self,
+        *,
+        db_adapter: DatabaseAdapter,
+    ):
+        assert db_adapter
+
+        self.db_adapter = db_adapter
+
+    def validate(
+        self,
+        *,
+        level: ValidationLevel,
+        workflow_definition: Dict[str, Any],
+        workflow_inputs: Optional[Dict[str, Any]],
+    ) -> ValidationResult:
+        """Validates the workflow definition (and inputs) based
+        on the provided 'level'."""
+        assert level in ValidationLevel
+        assert isinstance(workflow_definition, dict)
+        if workflow_inputs:
+            assert isinstance(workflow_inputs, dict)
+
+        if error := validate_schema(workflow_definition):
+            return ValidationResult(error=1, error_msg=[error])
+
+        return _VALIDATION_SUCCESS