Make socat state persist over reboots

Author: urfeex

manifest.yaml

@@ -26,6 +26,8 @@ artifacts:
       mounts:
         - mount: tmpfs:/tmp
           access: rw
+        - mount: persistent:/data
+          access: rw
       devices:
         - type: ttyTool
       ingress:

tool-comm-forwarder-backend/src/socat_server.py

@@ -1,6 +1,7 @@
 import subprocess
 import json
 import logging
+import os
 import sys
 
 import flask
@@ -20,6 +21,7 @@
 SOCAT_COMMAND = ["socat", f"tcp-l:{PORT},reuseaddr,fork", "file:/dev/ur-ttylink/ttyTool,nonblock,raw,waitlock=/tmp/lock_tty"]
 STOP_SOCAT_COOMAND = "killall -9 socat 2> /dev/null"
 IS_SOCAT_SERVER_RUNNING_COMMAND = f"socat /dev/null TCP:127.0.0.1:{PORT}"
+STATUS_FILENAME = "/data/socat_server_status.json"
 
 app = Flask(__name__)
 
@@ -46,30 +48,37 @@ def socat_server():
         flask.Response: A Flask response with a success key, telling whether the command was successful or not.
     """
     action = request.get_json()["action"]
+    response = None
     if action == "start":
         result = subprocess.Popen(SOCAT_COMMAND, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         try:
             # wait 0.2 seconds for errors 
             _, stderr = result.communicate(timeout=0.2)
             if result.returncode != 0:
                 logger.error(f"Failed to start socat server. Error message {stderr}")
-                return create_response({"success": False})
+
+                response = create_response({"success": False})
         except subprocess.TimeoutExpired: # If timeout expired the server is running
             logger.info("Started socat server")
-            return create_response({"success": True})
+            response = create_response({"success": True})
 
     elif action == "stop":
         result = subprocess.run(STOP_SOCAT_COOMAND, capture_output=True, shell=True)
         if result.returncode == 0:
             logger.info("Stopped socat server")
-            return create_response({"success": True})
+            response = create_response({"success": True})
         else:
             logger.error(f"Failed to stop socat server. Error message {result.stderr}")
-            return create_response({"success": False})
+            response = create_response({"success": False})
 
     else:
         logger.error(f"Unknown action received! Action received {action}")
-        return create_response({"success": False})
+        response = create_response({"success": False})
+
+    with open(STATUS_FILENAME, "wb") as status_file:
+        running_response = is_server_running()
+        status_file.write(running_response.data)
+    return response
 
 
 @app.route("/is_server_running", methods=["GET"])
@@ -85,5 +94,36 @@ def is_server_running(): # handle a message
     else:
         return create_response({"running": False})
 
+def recover_from_state(running: bool):
+    """Recovers the socat server to the given state
+
+    Args:
+        running (bool): Whether the server should be running or not
+    """
+    if running:
+        result = subprocess.Popen(SOCAT_COMMAND, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        try:
+            # wait 0.2 seconds for errors 
+            _, stderr = result.communicate(timeout=0.2)
+            if result.returncode != 0:
+                logger.error(f"Failed to recover socat server. Error message {stderr}")
+        except subprocess.TimeoutExpired: # If timeout expired the server is running
+            logger.info("Recovered socat server to running state")
+    else:
+        result = subprocess.run(STOP_SOCAT_COOMAND, capture_output=True, shell=True)
+        if result.returncode == 0:
+            logger.info("Recovered socat server to stopped state")
+        else:
+            logger.error(f"Failed to stop socat server during recovery. Error message {result.stderr}")
+
 if __name__ == '__main__':
-    serve(app, host='0.0.0.0', port=52762)
+    if os.path.exists(STATUS_FILENAME):
+        logger.info("Loading socat state from file")
+        with open(STATUS_FILENAME, "rb") as status_file:
+            bytes_data = status_file.read()
+            try:
+                data = json.loads(bytes_data.decode("utf-8"))
+                recover_from_state(data["running"])
+            except Exception as e:
+                logger.error(f"Failed to load socat server state from file. Error: {e}")
+    serve(app, host='0.0.0.0', port=52762)

tool-comm-forwarder-frontend/src/assets/i18n/en.json

@@ -3,7 +3,7 @@
     "nodes": {
       "universal-robots-tool-comm-forwarder-tool-comm-forwarder-application": {
         "title": "Tool Communication Forwarder",
-        "supportiveText": "URCap to forward toool communication to the network",
+        "supportiveText": "URCap to forward tool communication to the network",
         "description": {
           "line1": "URCapX to support relaying the RS-485 communication device in a UR robot to a remote PC.",
           "line2": "It starts a socat server to relay the tool communication device to the network socket on port 54321."
@@ -14,7 +14,7 @@
             "start": "Start",
             "stop": "Stop"
           },
-          "server-running-text": "Socat server is running on port 54321 forwarding tool communication to the network."
+          "server-running-text": "Socat server is running on port 54321 forwarding tool communication to the network. This state will persist after a robot restart."
         }
       }
     }