Fix test flakiness from TCP port contention (#388)

Eliminate the lock contention on test service TCP sockets leading to random,
frequent test failure.

Cargo-minimal.lock

@@ -1450,9 +1450,9 @@ dependencies = [
 
 [[package]]
 name = "ohttp-relay"
-version = "0.0.8"
+version = "0.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7850c40a0aebcba289d3252c0a45f93cba6ad4b0c46b88a5fc51dba6ddce8632"
+checksum = "4f8e8aef13b8327b680aaaca807aa11ba5979fc5858203e7b77c68128ede61a2"
 dependencies = [
  "futures",
  "http",

Cargo-recent.lock

@@ -1450,9 +1450,9 @@ dependencies = [
 
 [[package]]
 name = "ohttp-relay"
-version = "0.0.8"
+version = "0.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7850c40a0aebcba289d3252c0a45f93cba6ad4b0c46b88a5fc51dba6ddce8632"
+checksum = "4f8e8aef13b8327b680aaaca807aa11ba5979fc5858203e7b77c68128ede61a2"
 dependencies = [
  "futures",
  "http",

payjoin-cli/Cargo.toml

@@ -50,7 +50,7 @@ url = { version = "2.3.1", features = ["serde"] }
 [dev-dependencies]
 bitcoind = { version = "0.36.0", features = ["0_21_2"] }
 http = "1"
-ohttp-relay = "0.0.8"
+ohttp-relay = { version = "0.0.9", features = ["_test-util"] }
 once_cell = "1"
 payjoin-directory = { path = "../payjoin-directory", features = ["_danger-local-https"] }
 testcontainers = "0.15.0"

payjoin-cli/tests/e2e.rs

@@ -151,6 +151,11 @@ mod e2e {
             payjoin_sent.unwrap().unwrap_or(Some(false)).unwrap(),
             "Payjoin send was not detected"
         );
+
+        fn find_free_port() -> u16 {
+            let listener = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
+            listener.local_addr().unwrap().port()
+        }
     }
 
     #[cfg(feature = "v2")]
@@ -170,6 +175,7 @@ mod e2e {
         use url::Url;
 
         type Error = Box<dyn std::error::Error + 'static>;
+        type BoxSendSyncError = Box<dyn std::error::Error + Send + Sync>;
         type Result<T> = std::result::Result<T, Error>;
 
         static INIT_TRACING: OnceCell<()> = OnceCell::new();
@@ -178,18 +184,26 @@ mod e2e {
 
         init_tracing();
         let (cert, key) = local_cert_key();
-        let ohttp_relay_port = find_free_port();
-        let ohttp_relay = Url::parse(&format!("http://localhost:{}", ohttp_relay_port)).unwrap();
-        let directory_port = find_free_port();
-        let directory = Url::parse(&format!("https://localhost:{}", directory_port)).unwrap();
+        let docker: Cli = Cli::default();
+        let db = docker.run(Redis);
+        let db_host = format!("127.0.0.1:{}", db.get_host_port_ipv4(6379));
+        let (port, directory_handle) =
+            init_directory(db_host, (cert.clone(), key)).await.expect("Failed to init directory");
+        let directory = Url::parse(&format!("https://localhost:{}", port)).unwrap();
+
         let gateway_origin = http::Uri::from_str(directory.as_str()).unwrap();
+        let (ohttp_relay_port, ohttp_relay_handle) =
+            ohttp_relay::listen_tcp_on_free_port(gateway_origin)
+                .await
+                .expect("Failed to init ohttp relay");
+        let ohttp_relay = Url::parse(&format!("http://localhost:{}", ohttp_relay_port)).unwrap();
 
         let temp_dir = env::temp_dir();
         let receiver_db_path = temp_dir.join("receiver_db");
         let sender_db_path = temp_dir.join("sender_db");
         let result: Result<()> = tokio::select! {
-            res = ohttp_relay::listen_tcp(ohttp_relay_port, gateway_origin) => Err(format!("Ohttp relay is long running: {:?}", res).into()),
-            res = init_directory(directory_port, (cert.clone(), key)) => Err(format!("Directory server is long running: {:?}", res).into()),
+            res = ohttp_relay_handle => Err(format!("Ohttp relay is long running: {:?}", res).into()),
+            res = directory_handle => Err(format!("Directory server is long running: {:?}", res).into()),
             res = send_receive_cli_async(ohttp_relay, directory, cert, receiver_db_path.clone(), sender_db_path.clone()) => res.map_err(|e| format!("send_receive failed: {:?}", e).into()),
         };
 
@@ -479,13 +493,17 @@ mod e2e {
             Err("Timeout waiting for service to be ready".into())
         }
 
-        async fn init_directory(port: u16, local_cert_key: (Vec<u8>, Vec<u8>)) -> Result<()> {
-            let docker: Cli = Cli::default();
+        async fn init_directory(
+            db_host: String,
+            local_cert_key: (Vec<u8>, Vec<u8>),
+        ) -> std::result::Result<
+            (u16, tokio::task::JoinHandle<std::result::Result<(), BoxSendSyncError>>),
+            BoxSendSyncError,
+        > {
+            println!("Database running on {}", db_host);
             let timeout = Duration::from_secs(2);
-            let db = docker.run(Redis);
-            let db_host = format!("127.0.0.1:{}", db.get_host_port_ipv4(6379));
-            println!("Database running on {}", db.get_host_port_ipv4(6379));
-            payjoin_directory::listen_tcp_with_tls(port, db_host, timeout, local_cert_key).await
+            payjoin_directory::listen_tcp_with_tls_on_free_port(db_host, timeout, local_cert_key)
+                .await
         }
 
         // generates or gets a DER encoded localhost cert and key.
@@ -524,11 +542,6 @@ mod e2e {
         }
     }
 
-    fn find_free_port() -> u16 {
-        let listener = std::net::TcpListener::bind("127.0.0.1:0").unwrap();
-        listener.local_addr().unwrap().port()
-    }
-
     async fn cleanup_temp_file(path: &std::path::Path) {
         if let Err(e) = fs::remove_dir_all(path).await {
             eprintln!("Failed to remove {:?}: {}", path, e);

payjoin-directory/src/lib.rs

@@ -36,6 +36,67 @@ const ID_LENGTH: usize = 13;
 mod db;
 use crate::db::DbPool;
 
+#[cfg(feature = "_danger-local-https")]
+type BoxError = Box<dyn std::error::Error + Send + Sync>;
+
+#[cfg(feature = "_danger-local-https")]
+pub async fn listen_tcp_with_tls_on_free_port(
+    db_host: String,
+    timeout: Duration,
+    cert_key: (Vec<u8>, Vec<u8>),
+) -> Result<(u16, tokio::task::JoinHandle<Result<(), BoxError>>), BoxError> {
+    let listener = tokio::net::TcpListener::bind("[::]:0").await?;
+    let port = listener.local_addr()?.port();
+    println!("Directory server binding to port {}", listener.local_addr()?);
+    let handle = listen_tcp_with_tls_on_listener(listener, db_host, timeout, cert_key).await?;
+    Ok((port, handle))
+}
+
+// Helper function to avoid code duplication
+#[cfg(feature = "_danger-local-https")]
+async fn listen_tcp_with_tls_on_listener(
+    listener: tokio::net::TcpListener,
+    db_host: String,
+    timeout: Duration,
+    tls_config: (Vec<u8>, Vec<u8>),
+) -> Result<tokio::task::JoinHandle<Result<(), BoxError>>, BoxError> {
+    let pool = DbPool::new(timeout, db_host).await?;
+    let ohttp = Arc::new(Mutex::new(init_ohttp()?));
+    let tls_acceptor = init_tls_acceptor(tls_config)?;
+    // Spawn the connection handling loop in a separate task
+    let handle = tokio::spawn(async move {
+        while let Ok((stream, _)) = listener.accept().await {
+            let pool = pool.clone();
+            let ohttp = ohttp.clone();
+            let tls_acceptor = tls_acceptor.clone();
+            tokio::spawn(async move {
+                let tls_stream = match tls_acceptor.accept(stream).await {
+                    Ok(tls_stream) => tls_stream,
+                    Err(e) => {
+                        error!("TLS accept error: {}", e);
+                        return;
+                    }
+                };
+                if let Err(err) = http1::Builder::new()
+                    .serve_connection(
+                        TokioIo::new(tls_stream),
+                        service_fn(move |req| {
+                            serve_payjoin_directory(req, pool.clone(), ohttp.clone())
+                        }),
+                    )
+                    .with_upgrades()
+                    .await
+                {
+                    error!("Error serving connection: {:?}", err);
+                }
+            });
+        }
+        Ok(())
+    });
+    Ok(handle)
+}
+
+// Modify existing listen_tcp_with_tls to use the new helper
 pub async fn listen_tcp(
     port: u16,
     db_host: String,
@@ -73,41 +134,11 @@ pub async fn listen_tcp_with_tls(
     port: u16,
     db_host: String,
     timeout: Duration,
-    tls_config: (Vec<u8>, Vec<u8>),
-) -> Result<(), Box<dyn std::error::Error>> {
-    let pool = DbPool::new(timeout, db_host).await?;
-    let ohttp = Arc::new(Mutex::new(init_ohttp()?));
-    let bind_addr = SocketAddr::new(IpAddr::V6(Ipv6Addr::UNSPECIFIED), port);
-    let tls_acceptor = init_tls_acceptor(tls_config)?;
-    let listener = TcpListener::bind(bind_addr).await?;
-    while let Ok((stream, _)) = listener.accept().await {
-        let pool = pool.clone();
-        let ohttp = ohttp.clone();
-        let tls_acceptor = tls_acceptor.clone();
-        tokio::spawn(async move {
-            let tls_stream = match tls_acceptor.accept(stream).await {
-                Ok(tls_stream) => tls_stream,
-                Err(e) => {
-                    error!("TLS accept error: {}", e);
-                    return;
-                }
-            };
-            if let Err(err) = http1::Builder::new()
-                .serve_connection(
-                    TokioIo::new(tls_stream),
-                    service_fn(move |req| {
-                        serve_payjoin_directory(req, pool.clone(), ohttp.clone())
-                    }),
-                )
-                .with_upgrades()
-                .await
-            {
-                error!("Error serving connection: {:?}", err);
-            }
-        });
-    }
-
-    Ok(())
+    cert_key: (Vec<u8>, Vec<u8>),
+) -> Result<tokio::task::JoinHandle<Result<(), BoxError>>, BoxError> {
+    let addr = format!("0.0.0.0:{}", port);
+    let listener = tokio::net::TcpListener::bind(&addr).await?;
+    listen_tcp_with_tls_on_listener(listener, db_host, timeout, cert_key).await
 }
 
 #[cfg(feature = "_danger-local-https")]

payjoin/Cargo.toml

@@ -42,7 +42,7 @@ serde_json = "1.0.108"
 bitcoind = { version = "0.36.0", features = ["0_21_2"] }
 http = "1"
 payjoin-directory = { path = "../payjoin-directory", features = ["_danger-local-https"] }
-ohttp-relay = "0.0.8"
+ohttp-relay = { version = "0.0.9", features = ["_test-util"] }
 once_cell = "1"
 rcgen = { version = "0.11" }
 reqwest = { version = "0.12", default-features = false, features = ["rustls-tls"] }