From: Scott Worley <scottworley@scottworley.com>
Date: Tue, 10 Oct 2023 23:57:22 +0000 (-0700)
Subject: server: Bind port before messing with log files as a lock
X-Git-Tag: v0.1.0~7
X-Git-Url: http://git.scottworley.com/tattlekey/commitdiff_plain/5f5768318f897a20464ca177b5de64157afe0938?hp=0d4f2aa67ed92add9c371a49cc45daad8e529301

server: Bind port before messing with log files as a lock

Rather than messing with flock, fnctl-F_SETLK, etc., just bind the port
before touching the log file & let the failure to bind the port keep
two instances of the server from stepping on each others' log i/o.
---

diff --git a/server/src/main.rs b/server/src/main.rs
index 5edadbb..e7351db 100644
--- a/server/src/main.rs
+++ b/server/src/main.rs
@@ -93,9 +93,9 @@ fn open_log_for_writing() -> csv::Writer<std::fs::File> {
 }
 
 fn main() {
-    let mut log = open_log_for_writing();
-    let mut presses = HashMap::<MessageKey, Range>::new();
     let socket = UdpSocket::bind("0.0.0.0:29803").expect("couldn't bind to address");
+    let mut presses = HashMap::<MessageKey, Range>::new();
+    let mut log = open_log_for_writing();
     loop {
         let mut buf = [0; MESSAGE_SIZE];
         match socket.recv_from(&mut buf) {