From 5a481ae13be1e1f7f417a62fd523859809a34077 Mon Sep 17 00:00:00 2001
From: Christos Falas <raspberrymaker@gmail.com>
Date: Thu, 23 Jan 2025 10:36:08 +0000
Subject: [PATCH] feat: show when FeitCSI is not running on remote machines

---
 src/collection/ingest.py | 75 +++++++++++++++++++++++++++++-----------
 1 file changed, 55 insertions(+), 20 deletions(-)

diff --git a/src/collection/ingest.py b/src/collection/ingest.py
index 315aa73..31c6030 100644
--- a/src/collection/ingest.py
+++ b/src/collection/ingest.py
@@ -2,6 +2,8 @@ import logging
 import time
 import socket
 import multiprocessing as mp
+import threading
+import subprocess
 import struct
 from typing import Callable
 from datetime import datetime
@@ -17,45 +19,78 @@ Host = tuple[str, int]
 CSICallback = Callable[[npt.NDArray[np.complex128]], None]
 
 
-class FeitTransmitter:
+class FeitHost:
+    def __init__(self, host: Host, command: str):
+        self.command = command
+        self.host = host
+        self.logger = logging.getLogger(
+            f"{__name__}.{self.__class__.__name__}-{self.host[0]}"
+        )
+        self.checker = threading.Thread(target=self.check_continuous)
+        self.checker.start()
+
+    def check_connection(self):
+        feitcsi_status = subprocess.run(
+            f"ssh root@{self.host[0]} pgrep feitcsi",
+            check=False,
+            stdout=subprocess.DEVNULL,
+            shell=True,
+        )
+        return feitcsi_status.returncode == 0
+
+    def connect(self):
+        self.server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        self.server.connect(self.host)
+        self.server.send(b"stop\n")
+        self.server.send(self.command.encode())
+        self.logger.info(f"Connected to {self.host}")
+
+    def check_continuous(self):
+        """
+        Repeatedly check if the FeitCSI service is running
+
+        Because FeitCSI is using TCP, we will get no information if the service stops, or the computer is not reachable. In order to make debugging easier, this checks and logs continuously if the service is running.
+        """
+        last_status = False
+        while True:
+            if not self.check_connection():
+                self.logger.error(f"FeitCSI is not running on {self.host[0]}")
+                last_status = False
+            else:
+                if not last_status:
+                    self.connect()
+                last_status = True
+            time.sleep(1)
+
+
+class FeitTransmitter(FeitHost):
     def __init__(self):
-        self.inject_server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-        self.inject_server.connect(config.INJECT_HOST)
-        inject_start_string = (
+        command = (
             f"feitcsi --frequency {config.CENTRAL_FREQUENCY_MHZ} "
             f"--channel-width {config.CHANNEL_WIDTH} "
             f"--format {config.FRAME_FORMAT} "
             f"--mode inject -s 1 --verbose "
             f"--inject-delay {1_000_000 // config.SAMPLE_RATE}"
         )
-        self.inject_server.send(b"stop\n")
-        self.inject_server.send(inject_start_string.encode())
-        self.logger = logging.getLogger(f"{__name__}.{self.__class__.__name__}")
-        self.logger.info(f"Connected to {config.INJECT_HOST}")
+        super().__init__(config.INJECT_HOST, command)
 
 
-class FeitReceiver:
+class FeitReceiver(FeitHost):
     def __init__(self, host: Host):
-        self.host = host
-        self.server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-        self.server.connect(host)
-        self.start_string = (
+        command = (
             f"feitcsi --frequency {config.CENTRAL_FREQUENCY_MHZ} "
             f"--channel-width {config.CHANNEL_WIDTH} "
             f"--format {config.FRAME_FORMAT} "
             f"--mode measure"
         )
-        self.server.send(b"stop\n")
-        self.server.send(self.start_string.encode())
-        self.logger = logging.getLogger(
-            f"{__name__}.{self.__class__.__name__}-{self.host}"
-        )
-        self.logger.info(f"Connected to {self.host}")
+        super().__init__(host, command)
 
     def listen(self, queue: "mp.Queue[CSI]"):
         prev_time = datetime.now()
         self.logger.info("Listening for CSI data")
         while True:
+            while not hasattr(self, "server"):
+                time.sleep(0.1)
             # This is the max size of a UDP packet. The size of the actual CSI
             # packet will depend on the frame format and channel width, which
             # changes the number of subcarriers
@@ -157,7 +192,7 @@ def start_processing(csi_callback: CSICallback):
     processor = CSIProcessor({r.ip: r.queue for r in receivers})
 
     receiver_processes = [
-        mp.Process(target=r.receiver.listen, args=(r.queue,)) for r in receivers
+        threading.Thread(target=r.receiver.listen, args=(r.queue,)) for r in receivers
     ]
 
     for proc in receiver_processes: