From 4c1447bb5e75862ed4e5906ca2a6b190ae5c9e0c Mon Sep 17 00:00:00 2001
From: Athanasios Xygkis <athanasios.xygkis@epfl.ch>
Date: Mon, 14 Sep 2020 08:57:26 +0200
Subject: [PATCH] Add TCP barrier

---
 barrier.py | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100755 barrier.py

diff --git a/barrier.py b/barrier.py
new file mode 100755
index 0000000..e399ef6
--- /dev/null
+++ b/barrier.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+
+import argparse
+import socket
+
+def barrier(host, port, wait_for):
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        s.bind((host, port))
+        s.listen()
+
+        connections = []
+        addresses = []
+
+        while True:
+            conn, addr = s.accept()
+            connections.append(conn)
+            addresses.append(addr)
+            print("Connection from {}".format(addr))
+
+            if len(connections) == wait_for:
+                break
+
+        for conn in connections:
+            conn.close()
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument(
+        "--host",
+        default="0.0.0.0",
+        dest="host",
+        help="IP address where the barrier listens to (default: any)",
+    )
+
+    parser.add_argument(
+        "--port",
+        default=11000,
+        type=int,
+        dest="port",
+        help="TCP port where the barrier listens to (default: 11000)",
+    )
+
+    parser.add_argument(
+        "--processes",
+        required=True,
+        type=int,
+        dest="processes",
+        help="Number of processes the barrier waits for",
+    )
+
+    results = parser.parse_args()
+
+    print("Barrier listens on {}:{} and waits for {} processes".format(results.host, results.port, results.processes))
+    barrier(results.host, results.port, results.processes)
\ No newline at end of file