Implement close() functionality for meshcat viewer and zmqserver that hosts the three.js webpage

src/meshcat/servers/zmqserver.py

@@ -4,6 +4,7 @@
 import base64
 import os
 import re
+import signal
 import sys
 import subprocess
 import multiprocessing
@@ -406,10 +407,21 @@ def main():
     if results.open:
         webbrowser.open(bridge.web_url, new=2)
 
+    def cleanup():
+        bridge.zmq_socket.close()
+        bridge.context.destroy()
+
+    # Make sure also kill results in socket being closed otherwise ZMQbg/Reaper and IO processes might stay open
+    atexit.register(cleanup)
+    signal.signal(signal.SIGTERM, cleanup)
+    signal.signal(signal.SIGINT, cleanup)
+
     try:
         bridge.run()
     except KeyboardInterrupt:
         pass
+    finally:
+        cleanup()
 
 if __name__ == '__main__':
     main()

src/meshcat/visualizer.py

@@ -1,3 +1,4 @@
+import signal
 import webbrowser
 import umsgpack
 import numpy as np
@@ -79,6 +80,12 @@ def get_image(self, w, h):
         img = Image.open(io.BytesIO(img_bytes))
         return img
 
+    def close(self):
+        self.zmq_socket.close()
+        self.context.destroy()
+        if self.server_proc is not None:
+            self.server_proc.kill()
+            self.server_proc.wait()
 
 def srcdoc_escape(x):
     return x.replace("&", "&").replace('"', """)