Use string enum for status

Signed-off-by: M Q <mingmelvinq@nvidia.com>

Author: MMelQin

platforms/aidoc/README.md

@@ -72,7 +72,7 @@ sequenceDiagram
         REST Service-->>-Client: HTTP 409 Conflict
 
         Client->>+REST Service: GET /status
-        REST Service-->>-Client: HTTP 200 OK ("status": "BUSY")
+        REST Service-->>-Client: HTTP 200 OK ("status": "PROCESSING")
     end
 
     AppThread->>+AISpleenSegApp: Create instance(status_callback)
@@ -174,7 +174,7 @@ The script can be run multiple times or modified to loop with different output f
 -   **Description**: Checks the current status of the processor.
 -   **Success Response**:
     -   **Code**: 200 OK
-    -   **Content**: `{ "status": "IDLE" }` or `{ "status": "BUSY" }`
+    -   **Content**: `{ "status": "IDLE" }` or `{ "status": "PROCESSING" }`
 
 ### Process Data
 

platforms/aidoc/restful_app/app.py

@@ -16,12 +16,20 @@
 import os
 import sys
 import threading
+from enum import Enum
 from http import HTTPStatus
 
 import requests
 from flask import Flask, jsonify, request
 from flask_wtf.csrf import CSRFProtect
 
+# Processing status enum per Aidoc API specification.
+class ProcessingStatus(str, Enum):
+    INITIALIZING = "INITIALIZING"
+    IDLE = "IDLE"
+    PROCESSING = "PROCESSING"
+    ERROR = "ERROR"
+
 # The MONAI Deploy application to be wrapped.
 # This can be changed to any other application in the repository.
 # Provide the module path and the class name of the application.
@@ -40,7 +48,7 @@
 logging.basicConfig(stream=sys.stdout, level=logging.INFO)
 
 # Global state to track processing status. A lock is used for thread safety.
-PROCESSING_STATUS = "IDLE"
+PROCESSING_STATUS = ProcessingStatus.IDLE
 PROCESSING_LOCK = threading.Lock()
 
 
@@ -87,7 +95,7 @@ def app_status_callback(summary: str):
 
     try:
         logging.info("Starting processing in a background thread.")
-        set_processing_status("BUSY")
+        set_processing_status(ProcessingStatus.PROCESSING)
 
         # Set environment variables for the MONAI Deploy application.
         # The application context will pick these up.
@@ -118,7 +126,7 @@ def app_status_callback(summary: str):
         app_status_callback(json.dumps(callback_msg))
 
     finally:
-        set_processing_status("IDLE")
+        set_processing_status(ProcessingStatus.IDLE)
         logging.info("Processor is now IDLE.")
 
 
@@ -132,7 +140,7 @@ def status():
 @csrf.exempt
 def process():
     """Endpoint to start a new processing job."""
-    if get_processing_status() == "BUSY":
+    if get_processing_status() == ProcessingStatus.PROCESSING:
         return jsonify({"error": "Processor is busy."}), HTTPStatus.CONFLICT
 
     data = request.get_json()