fix: the web service, the metrics service and the bootstrap server log a failure in one line instead of a traceback, and nothing when a client goes away.

debian-package/src/usr/lib/vpn-router/bootstrap

@@ -8,6 +8,7 @@ the logs.
 """
 
 import subprocess
+import sys
 from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
 
 PORT = 17081
@@ -51,5 +52,15 @@ class Handler(BaseHTTPRequestHandler):
         self.wfile.write(body)
 
 
+def failed(request, client_address):
+    """Log a failed request in one line, and nothing when the client went away."""
+    failure = sys.exc_info()[1]
+    if not isinstance(failure, ConnectionError):
+        print(f'a request from {client_address[0]} failed: {type(failure).__name__}: {failure}', file=sys.stderr, flush=True)
+
+
 if __name__ == '__main__':
-    ThreadingHTTPServer(('', PORT), Handler).serve_forever()
+    sys.excepthook = lambda kind, value, _: print(f'failed: {kind.__name__}: {value}', file=sys.stderr, flush=True)
+    server = ThreadingHTTPServer(('', PORT), Handler)
+    server.handle_error = failed
+    server.serve_forever()

debian-package/src/usr/lib/vpn-router/vpnrouter_serve.py

@@ -4,6 +4,7 @@ Only the Python standard library is used, so the bootstrap server, which must ru
 is broken, can use it.
 """
 
+import sys
 import threading
 import time
 from http.server import ThreadingHTTPServer
@@ -14,9 +15,21 @@ def serve(wanted, handler, log, interval):
 
     wanted answers ([(address, port), ...], '') or ([], the reason not to listen). A server whose
     place is no longer wanted is stopped, and a new one listens at each new place; a place that
-    cannot be bound is tried again the next round. Every new message is logged with log. Does
-    not return.
+    cannot be bound is tried again the next round. Every new message is logged with log. A request
+    whose client went away is not logged; any other exception a request, a thread or the process
+    does not handle is logged with log in one line, without a traceback. Does not return.
     """
+    def failed(request, client_address):
+        failure = sys.exc_info()[1]
+        if not isinstance(failure, ConnectionError):
+            log(f'a request from {client_address[0]} failed: {type(failure).__name__}: {failure}')
+
+    def thread_failed(hook):
+        if not issubclass(hook.exc_type, (SystemExit, ConnectionError)):
+            log(f'{hook.thread.name if hook.thread else "a thread"} failed: {hook.exc_type.__name__}: {hook.exc_value}')
+
+    threading.excepthook = thread_failed
+    sys.excepthook = lambda kind, value, _: log(f'failed: {kind.__name__}: {value}')
     servers, reported = {}, None
     while True:
         targets, reason = wanted()
@@ -34,6 +47,7 @@ def serve(wanted, handler, log, interval):
             except OSError as exc:
                 messages.append(f'cannot listen on {target[0]}:{target[1]}: {exc}')
                 continue
+            server.handle_error = failed
             thread = threading.Thread(target=server.serve_forever, name=f'server {target[0]}', daemon=True)
             thread.start()
             servers[target] = (server, thread)