Replace signal-based MT closing with a TCP message

craftium/craftium_env.py

@@ -1,12 +1,10 @@
 import os
 from typing import Optional, Any
-import time
 
 from .mt_channel import MtChannel
 from .minetest import Minetest
 
 import numpy as np
-
 from gymnasium import Env
 from gymnasium.spaces import Dict, Discrete, Box
 
@@ -125,10 +123,11 @@ def reset(
         super().reset(seed=seed)
         self.timesteps = 0
 
-        # close the active (if any) channel with mintest
-        self.mt_chann.close_conn()
-        # kill the active mt process if there's any
-        self.mt.kill_process()
+        if self.mt_chann.conn is not None:
+            self.mt_chann.send_termination()
+            self.mt_chann.close_conn()
+            self.mt.close_pipes()
+            self.mt.wait_close()
 
         # start the new MT process
         self.mt.start_process()
@@ -198,6 +197,9 @@ def render(self):
             return self.last_observation
 
     def close(self):
-        self.mt_chann.close()
-        self.mt.kill_process()
+        if self.mt_chann.conn is not None:
+            self.mt_chann.send_termination()
+            self.mt_chann.close()
+            self.mt.close_pipes()
+            self.mt.wait_close()
         self.mt.clear()

craftium/minetest.py

@@ -1,11 +1,8 @@
 import os
 from typing import Optional, Any
 import subprocess
-import multiprocessing
 from uuid import uuid4
 import shutil
-import signal
-import atexit
 
 
 def is_minetest_build_dir(path: os.PathLike) -> bool:
@@ -127,17 +124,6 @@ def __init__(
         if headless:
             self.mt_env["SDL_VIDEODRIVER"] = "offscreen"
 
-        # register the cleanup function to be called on exit
-        atexit.register(self._kill_proc)
-
-    def _kill_proc(self):
-        if self.proc is not None:
-            # send kill signal to the process
-            os.kill(self.proc.pid, signal.SIGKILL)
-            # wait for the process to finish (timeout at 30s)
-            self.proc.wait(timeout=30)
-            self.proc = None
-
     def start_process(self):
         if self.pipe_proc:
             # open files for piping stderr and stdout into
@@ -160,16 +146,18 @@ def start_process(self):
             **kwargs,
         )
 
-    def kill_process(self):
+    def wait_close(self):
+        if self.proc is not None:
+            self.proc.wait()
+
+    def close_pipes(self):
         # close the files where the process is being piped
         # into berfore the process itself
         if self.stderr is not None:
             self.stderr.close()
         if self.stdout is not None:
             self.stdout.close()
 
-        self._kill_proc()
-
     def clear(self):
         # delete the run's directory
         if os.path.exists(self.run_dir):

craftium/mt_channel.py

@@ -49,16 +49,18 @@ def receive(self):
 
         return img, reward, termination
 
-    def send(self, keys: list[int], mouse_x: int, mouse_y: int):
+    def send(self, keys: list[int], mouse_x: int, mouse_y: int, terminate: bool = False):
         assert len(keys) == 21, f"Keys list must be of length 21 and is {len(keys)}"
 
         mouse = list(struct.pack("<h", mouse_x)) + list(struct.pack("<h", mouse_y))
 
-        self.conn.sendall(bytes(keys + mouse))
+        self.conn.sendall(bytes(keys + mouse + [1 if terminate else 0]))
+
+    def send_termination(self):
+        self.send(keys=[0]*21, mouse_x=0, mouse_y=0, terminate=True)
 
     def close(self):
-        if self.conn is not None:
-            self.conn.close()
+        self.close_conn()
         self.s.close()
 
     def close_conn(self):

src/client/client.cpp

@@ -168,6 +168,20 @@ void Client::startPyConn()
         exit(EXIT_FAILURE);
     }
 
+    /*
+    struct timeval timeout;
+    timeout.tv_sec = 2;  // timeout time in seconds
+    timeout.tv_usec = 0;
+    if (setsockopt(py_sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof(timeout)) < 0) {
+        perror("[ERROR] PyConn setsockopt failed");
+        exit(EXIT_FAILURE);
+    }
+    if (setsockopt(py_sockfd, SOL_SOCKET, SO_SNDTIMEO, (const char*)&timeout, sizeof(timeout)) < 0) {
+        perror("[ERROR] PyConn setsockopt failed");
+        exit(EXIT_FAILURE);
+    }
+    */
+
     py_servaddr = (struct sockaddr_in*) malloc(sizeof(struct sockaddr_in));
 
     memset(py_servaddr, 0, sizeof(*py_servaddr));
@@ -186,7 +200,7 @@ void Client::startPyConn()
 }
 
 void Client::pyConnStep() {
-    char actions[25];
+    char actions[26];
     int n_send, n_recv, W, H, obs_rwd_buffer_size;
     u32 c; // stores the RGBA pixel color
 
@@ -327,7 +341,12 @@ void Client::pyConnStep() {
     /* If sending or receiving went wrong, print an error message and quit */
     if (n_send + n_recv < 2) {
         printf("[!!] Python client disconnected. Shutting down...\n");
-        exit(43);
+        exit(EXIT_FAILURE);
+    }
+
+    if (actions[25]) {
+        printf("[NOTE] Termination signal received, exiting...\n");
+        exit(0);
     }
 }
 

src/client/craftium.h

@@ -49,21 +49,6 @@ inline int syncServerInit() {
     address.sin_addr.s_addr = INADDR_ANY;
     address.sin_port = htons(0); // let the OS choose an empty port
 
-    // Set receive and send timeout on the socket
-    struct timeval timeout;
-    timeout.tv_sec = 10;  // timeout time in seconds
-    timeout.tv_usec = 0;
-    if (setsockopt(server_fd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof(timeout)) < 0) {
-        perror("[SyncServer] setsockopt failed");
-        exit(EXIT_FAILURE);
-    }
-
-    int opt = 1;
-    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
-        perror("[SyncServer] setsockopt SO_REUSEADDR failed");
-        exit(EXIT_FAILURE);
-    }
-
     // Bind the server's socket to a port
     if (bind(server_fd, (struct sockaddr*)&address,
              sizeof(address))
@@ -117,14 +102,6 @@ inline int syncClientInit() {
         exit(EXIT_FAILURE);
     }
 
-    struct timeval timeout;
-    timeout.tv_sec = 10;  // timeout time in seconds
-    timeout.tv_usec = 0;
-    if (setsockopt(sync_client_fd, SOL_SOCKET, SO_SNDTIMEO, (const char*)&timeout, sizeof(timeout)) < 0) {
-        perror("[SyncClient] setsockopt failed");
-        exit(EXIT_FAILURE);
-    }
-
     // Connect to the server @ sync_port
     if ((status
          = connect(sync_client_fd, (struct sockaddr*)&serv_addr,
@@ -145,12 +122,7 @@ inline void syncServerStep() {
     char msg[2];
     if (read(sync_conn_fd, msg, 2) <= 0) {
         perror("[syncServerStep] Step failed");
-        if (errno == EAGAIN) {
-            fprintf(stderr, "[SyncServerStep] Warning: timeout\n" );
-        } else {
-            fprintf(stderr, "Error code is %d, exiting...\n", errno);
-            exit(EXIT_FAILURE);
-        }
+        exit(EXIT_FAILURE);
     }
 }