bind to localhost by default, allow overwriting per command line arg

Author: srittau

README.md

@@ -12,4 +12,5 @@ Usage
 
 Supported options:
 
+  * `-b, --bind [ADDRESS]` IP addresses to listen on, defaults to 127.0.0.1
   * `-p, --port [PORT]` SMTP port to listen on

fakesmtpd/args.py

@@ -6,6 +6,9 @@
 def parse_args(argv: List[str]) -> Any:
     parser = argparse.ArgumentParser(
         description="SMTP server for testing mail functionality")
+    parser.add_argument(
+        "--bind", "-b", nargs="?", default="127.0.0.1",
+        help="IP address range to listen to")
     parser.add_argument(
         "--port", "-p", type=int, nargs="?", default=SMTP_PORT,
         help="SMTP port to listen on")

fakesmtpd/server.py

@@ -2,6 +2,7 @@
 import logging
 import signal
 import sys
+from typing import Optional
 
 from fakesmtpd.args import parse_args
 from fakesmtpd.connection import handle_connection
@@ -11,16 +12,16 @@ def main() -> None:
     logging.basicConfig(level=logging.INFO)
     args = parse_args(sys.argv)
     try:
-        run_server(args.port)
+        run_server(args.bind, args.port)
     except PermissionError as exc:
         print(str(exc), file=sys.stderr)
         sys.exit(1)
 
 
-def run_server(port: int) -> None:
+def run_server(host: Optional[str], port: int) -> None:
     loop = asyncio.get_event_loop()
     loop.add_signal_handler(signal.SIGINT, loop.stop)
     loop.add_signal_handler(signal.SIGTERM, loop.stop)
-    s = asyncio.start_server(handle_connection, port=port)
+    s = asyncio.start_server(handle_connection, host=host, port=port)
     loop.run_until_complete(s)
     loop.run_forever()