From e8afa00bafb187a37a2707eb9a5b868f4f5688c0 Mon Sep 17 00:00:00 2001
From: Daniel Gushchyan <d.gushchyan@gmail.com>
Date: Thu, 23 Nov 2023 01:30:49 -0800
Subject: [PATCH] Auto-switch port when getting AddrInUse error

---
 crates/re_web_viewer_server/src/lib.rs | 11 +++++++++++
 crates/re_ws_comms/src/server.rs       | 14 +++++++++++---
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/crates/re_web_viewer_server/src/lib.rs b/crates/re_web_viewer_server/src/lib.rs
index 6e03322ad4e8..f4761fc32984 100644
--- a/crates/re_web_viewer_server/src/lib.rs
+++ b/crates/re_web_viewer_server/src/lib.rs
@@ -207,9 +207,20 @@ impl WebViewerServer {
     /// ```
     pub fn new(bind_ip: &str, port: WebViewerServerPort) -> Result<Self, WebViewerServerError> {
         let bind_addr = format!("{bind_ip}:{port}").parse()?;
+
         let server = hyper::Server::try_bind(&bind_addr)
+            .or_else(|hyper_err| {
+                if hyper_err.to_string().contains("Address already in use") {
+                    let fallback_addr = format!("{bind_ip}:0").parse().map_err(|_err| hyper_err)?;
+
+                    hyper::Server::try_bind(&fallback_addr)
+                } else {
+                    Err(hyper_err)
+                }
+            })
             .map_err(|err| WebViewerServerError::BindFailed(port, err))?
             .serve(MakeSvc);
+
         Ok(Self { server })
     }
 
diff --git a/crates/re_ws_comms/src/server.rs b/crates/re_ws_comms/src/server.rs
index 6b6533d87f2b..3cc5d41d42b6 100644
--- a/crates/re_ws_comms/src/server.rs
+++ b/crates/re_ws_comms/src/server.rs
@@ -33,9 +33,17 @@ impl RerunServer {
     pub async fn new(bind_ip: String, port: RerunServerPort) -> Result<Self, RerunServerError> {
         let bind_addr = format!("{bind_ip}:{port}");
 
-        let listener = TcpListener::bind(&bind_addr)
-            .await
-            .map_err(|err| RerunServerError::BindFailed(port, err))?;
+        let listener = match TcpListener::bind(&bind_addr).await {
+            Ok(listener) => listener,
+            Err(err) if err.kind() == std::io::ErrorKind::AddrInUse => {
+                let bind_addr = format!("{bind_ip}:0");
+
+                TcpListener::bind(&bind_addr)
+                    .await
+                    .map_err(|err| RerunServerError::BindFailed(RerunServerPort(0), err))?
+            }
+            Err(err) => return Err(RerunServerError::BindFailed(port, err)),
+        };
 
         let slf = Self {
             local_addr: listener.local_addr()?,