From 12039fb8626823c6cd9a1d883b43ca1ae5dcf9df Mon Sep 17 00:00:00 2001
From: Matthew Tran <matthewlamtran@berkeley.edu>
Date: Fri, 11 Apr 2025 03:23:52 -0700
Subject: [PATCH] lower terraria idle draw further

---
 compose.yml         |  2 +-
 terraria/Dockerfile |  6 +--
 terraria/entry.py   | 90 +++++++++++++++++++++++++++++++++++++++++++++
 terraria/entry.sh   | 14 -------
 4 files changed, 93 insertions(+), 19 deletions(-)
 create mode 100644 terraria/entry.py
 delete mode 100644 terraria/entry.sh

diff --git a/compose.yml b/compose.yml
index 99f8b81..5a58a0e 100644
--- a/compose.yml
+++ b/compose.yml
@@ -112,7 +112,7 @@ services:
   terraria:
     restart: always
     build: terraria/.
-    entrypoint: ["/bin/sh", "/home/me/entry.sh"]
+    entrypoint: ["/usr/bin/python3", "/home/me/entry.py"]
     ports:
       - "7777:7777"
     networks:
diff --git a/terraria/Dockerfile b/terraria/Dockerfile
index 216bd43..e0a2119 100644
--- a/terraria/Dockerfile
+++ b/terraria/Dockerfile
@@ -1,7 +1,7 @@
 FROM ubuntu:24.04
 
 RUN apt-get update && apt-get -y upgrade
-RUN apt-get install -y wget unzip dotnet-runtime-8.0
+RUN apt-get install -y wget unzip python3 iproute2 dotnet-runtime-8.0
 
 RUN groupadd -g 2002 me && useradd -u 2002 -g 2002 -m me
 USER me
@@ -14,12 +14,10 @@ RUN unzip tModLoader.zip -d server && rm tModLoader.zip
 RUN chmod +x server/start-tModLoaderServer.sh
 RUN mkdir server/tModLoader-Logs && touch server/tModLoader-Logs/server.log
 RUN echo "" > server/LaunchUtils/InstallDotNet.sh
-COPY --chown=me:me entry.sh ./
+COPY --chown=me:me entry.py ./
 COPY --chown=me:me config.default ./config.txt
 COPY --chown=me:me password.default ./password.txt
 COPY --chown=me:me config.tx[t] password.tx[t] ./
 
 # To add mods, install them on the client and copy over the .tmod files to mods/
 # Then modify/create mods/enabled.json and add the desired mods to enable
-
-# TODO reduce idle cpu when no players...
diff --git a/terraria/entry.py b/terraria/entry.py
new file mode 100644
index 0000000..99c31bd
--- /dev/null
+++ b/terraria/entry.py
@@ -0,0 +1,90 @@
+#!/usr/bin/env python3
+
+import logging
+import os
+import signal
+import socket
+import subprocess
+import time
+
+class Runner:
+    def __init__(self):
+        self.server = None
+        signal.signal(signal.SIGINT, self.terminate)
+        signal.signal(signal.SIGTERM, self.terminate)
+
+    def run(self):
+        while True:
+            # low-power idle waiting for players
+            logging.info("waiting for connection attempt...")
+            s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            s.bind(("0.0.0.0", 7777))
+            s.listen()
+            (c, addr) = s.accept()
+            c.close()
+            s.close()
+            logging.info(f"attempted connection from {addr}, starting server...")
+
+            # start server
+            with open("/home/me/password.txt", "r") as f:
+                password = f.read()
+            self.server = subprocess.Popen([
+                "/bin/bash",
+                "/home/me/server/start-tModLoaderServer.sh", 
+                "-nosteam",
+                "-config", "/home/me/config.txt",
+                "-pass", f"{password}",
+            ], stdin=subprocess.PIPE, start_new_session=True)
+            while not self.started():
+                time.sleep(1.0)
+
+            # wait until no connections for timeout
+            logging.info("server started, waiting until idle for 30s...")
+            idle_start = time.time()
+            while (time.time() - idle_start) < 30.0:
+                time.sleep(1.0)
+                if self.playing():
+                    idle_start = time.time()
+
+            # stop server
+            self.exit()
+            while self.started():
+                time.sleep(1.0)
+
+    def started(self):
+        return b"LISTEN" in subprocess.check_output([
+            "ss", "-tln", "( sport = :7777 )"])
+
+    def playing(self):
+        return b"ESTAB" in subprocess.check_output([
+            "ss", "-tn", "( sport = :7777 )"])
+
+    def exit(self):
+        if self.server:
+            logging.info("shutting down server...")
+            self.server.stdin.write(b"exit\n")
+            self.server.stdin.flush()
+            timeout, start = True, time.time()
+            while (time.time() - start) < 8.0:
+                if self.server.poll() is not None:
+                    timeout = False
+                    break
+                time.sleep(0.25)
+            if timeout:
+                logging.error("forcefully shutting down server...")
+                os.killpg(os.getpgid(self.server.pid), signal.SIGKILL)
+        self.server = None
+
+    def terminate(self, signum, frame):
+        self.exit()
+        exit(0)
+
+if __name__ == "__main__":
+    logging.basicConfig(
+        format="[%(asctime)s] [%(levelname)s] %(message)s",
+        level=logging.INFO,
+        datefmt="%Y-%m-%d %H:%M:%S",
+    )
+    runner = Runner()
+    runner.run()
diff --git a/terraria/entry.sh b/terraria/entry.sh
deleted file mode 100644
index 7656bbb..0000000
--- a/terraria/entry.sh
+++ /dev/null
@@ -1,14 +0,0 @@
-#!/bin/sh
-
-cleanup() {
-    echo "exit\n" > cmd
-}
-
-trap 'cleanup' TERM
-
-rm cmd
-mkfifo cmd
-tail -f cmd | ./server/start-tModLoaderServer.sh -nosteam -config ../config.txt -pass $(cat password.txt) &
-echo "help\n" > cmd # shell waits for FIFO to be opened for writing before starting program!
-wait $! # wait for SIGTERM
-wait $! # wait for server to stop