adding signal handlers on backend

Author: shivaahir158

backend/restapi_server.py

@@ -1,10 +1,7 @@
-#
-#  Copyright (C) 2024 RapidSilicon
-#  Authorized use only
-#
 import argparse
 import os
 import sys
+import signal
 from flask import Flask, request, jsonify
 from flasgger import Swagger
 from submodule.rs_device_manager import RsDeviceManager
@@ -19,72 +16,88 @@
 from api.utils import attrs_api
 from api.project import project_api
 
-#
-# Main entry point
-#
+# Create Flask app
+app = Flask(__name__)
+app.url_map.strict_slashes = False
+
+# Set up Swagger for API documentation
+swagger_template = {
+    "swagger": "2.0",
+    "info": {
+        "title": "RPE Backend API",
+        "description": "The RPE Backend APIs consumed by the RPE frontend for power and thermal estimation of Rapid Silicon devices.",
+        "version": "0.1.0"
+    }
+}
+swagger = Swagger(app, template=swagger_template)
+
+# Register API blueprints with the Flask app
+app.register_blueprint(device_api)
+app.register_blueprint(clock_api)
+app.register_blueprint(dsp_api)
+app.register_blueprint(fabric_le_api)
+app.register_blueprint(bram_api)
+app.register_blueprint(io_api)
+app.register_blueprint(peripherals_api)
+app.register_blueprint(attrs_api)
+app.register_blueprint(project_api)
+
+# Hook up request signal to log requests from the UI
+@app.before_request
+def before_request():
+    log(f"{request.method} {request.url}")
+
+@app.after_request
+def after_request(response):
+    log(f"{request.method} {request.url} {response.status_code} - DONE")
+    return response
+
+# Graceful shutdown function
+def shutdown_server():
+    log("Shutting down server...")
+    func = request.environ.get('werkzeug.server.shutdown')
+    if func is not None:
+        func()
+    else:
+        log("Server shutdown function not found.", RsLogLevel.ERROR)
+
+# Signal handler for smooth shutdown
+def signal_handler(signal_received, frame):
+    log(f"Signal {signal_received} received, initiating shutdown...")
+    shutdown_server()
+    sys.exit(0)
+
+# Register the signal handler for SIGINT (Ctrl+C) and SIGTERM
+signal.signal(signal.SIGINT, signal_handler)
+signal.signal(signal.SIGTERM, signal_handler)
+
 def main():
-    # create and parse command line args
-    parser = argparse.ArgumentParser(description='Rapid Power Estimator Rest API Server command-line arguments.')
-    parser.add_argument('device_file', type=str, help='Path to the input device xml file')
+    # Parse command-line arguments
+    parser = argparse.ArgumentParser(description='Rapid Power Estimator REST API Server command-line arguments.')
+    parser.add_argument('device_file', type=str, help='Path to the input device XML file')
     parser.add_argument('--port', type=int, default=5000, help='Specify TCP Port to use for REST server')
     parser.add_argument('--debug', default=False, action='store_true', help='Enable/Disable debug mode')
     parser.add_argument('--logfile', type=str, default="rpe.log", help='Specify log file name')
-    parser.add_argument('--maxbytes', type=int, default=2048, help='Specify maximun log file size in kilobytes before rollover')
-    parser.add_argument('--backupcount', type=int, default=20, help='Specify no. of backup log files')
+    parser.add_argument('--maxbytes', type=int, default=2048, help='Specify maximum log file size in kilobytes before rollover')
+    parser.add_argument('--backupcount', type=int, default=20, help='Specify number of backup log files')
     args = parser.parse_args()
 
-    # setup app logger
-    log_setup(filename=args.logfile, max_bytes=args.maxbytes*1024, backup_count=args.backupcount)
+    # Set up logger
+    log_setup(filename=args.logfile, max_bytes=args.maxbytes * 1024, backup_count=args.backupcount)
 
     # Check if the device_file exists
-    if os.path.exists(args.device_file) == False:
+    if not os.path.exists(args.device_file):
         log(f"Device file '{args.device_file}' does not exist.", RsLogLevel.ERROR)
         sys.exit(1)
 
     # Parse Device XML file into Device List
     devicemanager = RsDeviceManager.get_instance()
     devicemanager.load_xml(args.device_file)
 
-    # create flask app object
-    app = Flask(__name__)
-    app.url_map.strict_slashes = False
-
-    # auto generate restapi documentation
-    template = {
-        "swagger": "2.0",
-        "info": {
-            "title": "RPE Backend API",
-            "description": "The RPE Backend APIs which consumed by the RPE frontend for power and thermal estimation of the Rapid Silicon devices.",
-            "version": "0.1.0"
-        }
-    }
-    swagger = Swagger(app, template=template)
-
-    # bind device api objects onto the flask app
-    app.register_blueprint(device_api)
-    app.register_blueprint(clock_api)
-    app.register_blueprint(dsp_api)
-    app.register_blueprint(fabric_le_api)
-    app.register_blueprint(bram_api)
-    app.register_blueprint(io_api)
-    app.register_blueprint(peripherals_api)
-    app.register_blueprint(attrs_api)
-    app.register_blueprint(project_api)
-
-    # hook up request signal to log request by UI
-    @app.before_request
-    def before_request():
-        log(f"{request.method} {request.url}")
-
-    @app.after_request
-    def after_request(response):
-        log(f"{request.method} {request.url} {response.status_code} - DONE")
-        return response
-
-    # log app server started
+    # Log server start message
     log("App server is running...")
 
-    # Start Rest API server
+    # Start the Flask app
     app.run(debug=args.debug, port=args.port)
 
 if __name__ == "__main__":