Auto-find available port and version-check running instances (#13)

- Bind TCP listener before SMB setup; auto-increment port on AddrInUse
  (up to 100 tries) so the proxy never fails on a busy port.
- Add version to Server header (spiceio/X.Y.Z) so the setup action can
  detect stale instances.
- Setup action now compares running version against installed binary and
  replaces outdated instances. Bare "Server: spiceio" (pre-versioned
  builds) is treated as outdated.
- Readiness loop discovers actual endpoint from SPICEIO_LOG_FILE,
  handling port auto-increment correctly.

Author: lukekim

.github/actions/setup/action.yml

@@ -80,13 +80,29 @@ runs:
       run: |
         set -euo pipefail
 
-        ENDPOINT="http://${SPICEIO_BIND}"
-
-        # Skip if spiceio is already listening on the requested address
-        if curl -sf -I "$ENDPOINT/" 2>/dev/null | grep -qi "server: spiceio"; then
-          echo "spiceio already running at $ENDPOINT — skipping start"
-          echo "endpoint=$ENDPOINT" >> "$GITHUB_OUTPUT"
-          exit 0
+        # Check if spiceio is already listening on the requested address
+        WANT_VERSION=$(spiceio --version | awk '{print $2}')
+        RUNNING_HEADER=$(curl -sf -I "http://${SPICEIO_BIND}/" 2>/dev/null | grep -i '^server:.*spiceio' | tr -d '\r' || true)
+        if [[ -n "$RUNNING_HEADER" ]]; then
+          # Extract version from "Server: spiceio/X.Y.Z"; bare "Server: spiceio"
+          # (no slash) means a pre-versioned build — treat as outdated.
+          RUNNING_VERSION="${RUNNING_HEADER##*/}"
+          RUNNING_VERSION="${RUNNING_VERSION// /}"
+          if [[ "$RUNNING_HEADER" == */* && "$RUNNING_VERSION" == "$WANT_VERSION" ]]; then
+            echo "spiceio $WANT_VERSION already running at http://${SPICEIO_BIND} — skipping start"
+            echo "endpoint=http://${SPICEIO_BIND}" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          # Old or mismatched version — kill it so we can replace it
+          mapfile -t OLD_PIDS < <(lsof -ti "tcp:${SPICEIO_BIND##*:}" -sTCP:LISTEN 2>/dev/null || true)
+          if (( ${#OLD_PIDS[@]} > 0 )); then
+            echo "replacing spiceio ${RUNNING_VERSION:-unknown} (PID(s) ${OLD_PIDS[*]}) with $WANT_VERSION"
+            kill "${OLD_PIDS[@]}" 2>/dev/null || true
+            for i in $(seq 1 10); do
+              lsof -ti "tcp:${SPICEIO_BIND##*:}" -sTCP:LISTEN >/dev/null 2>&1 || break
+              sleep 1
+            done
+          fi
         fi
 
         # Parse smb://user:pass@server:port/share
@@ -127,21 +143,28 @@ runs:
         export SPICEIO_SMB_SERVER SPICEIO_SMB_PORT SPICEIO_SMB_USER SPICEIO_SMB_PASS SPICEIO_SMB_SHARE
         export SPICEIO_BUCKET SPICEIO_REGION SPICEIO_BIND
 
+        SPICEIO_LOG="${RUNNER_TEMP}/spiceio.log"
+        : > "$SPICEIO_LOG"
+        export SPICEIO_LOG_FILE="$SPICEIO_LOG"
+
         spiceio &
         PID=$!
-        echo "endpoint=$ENDPOINT" >> "$GITHUB_OUTPUT"
 
-        # Wait for readiness
+        # Wait for spiceio to report its actual listening address (port may
+        # auto-increment if the requested port was busy).
         echo "Waiting for spiceio on ${SPICEIO_BIND}..."
+        ENDPOINT=""
         for i in $(seq 1 30); do
-          if curl -sf -o /dev/null "$ENDPOINT/" 2>/dev/null; then
-            echo "spiceio ready at $ENDPOINT (PID $PID)"
-            exit 0
-          fi
           if ! kill -0 "$PID" 2>/dev/null; then
             echo "::error::spiceio exited unexpectedly"
             exit 1
           fi
+          ENDPOINT=$(grep 'listening on' "$SPICEIO_LOG" 2>/dev/null | grep -o 'http://[^ ]*' | tail -1 || true)
+          if [[ -n "$ENDPOINT" ]] && curl -sf -I "$ENDPOINT/" 2>/dev/null | grep -qi "server: spiceio"; then
+            echo "spiceio ready at $ENDPOINT (PID $PID)"
+            echo "endpoint=$ENDPOINT" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
           sleep 1
         done
         echo "::error::spiceio failed to start within 30s"

src/main.rs

@@ -92,6 +92,32 @@ async fn main() {
 
     let config = Config::from_env();
 
+    // Bind TCP listener early (before SMB setup). If the port is taken,
+    // auto-increment until an available port is found.
+    let (listener, bind_addr) = {
+        let mut addr = config.bind_addr;
+        let start_port = addr.port();
+        loop {
+            match TcpListener::bind(addr).await {
+                Ok(l) => break (l, addr),
+                Err(e) if e.kind() == std::io::ErrorKind::AddrInUse => {
+                    let next = match addr.port().checked_add(1) {
+                        Some(n) if n - start_port <= 100 => n,
+                        _ => {
+                            serr!("no available port in range {start_port}–{}", addr.port());
+                            std::process::exit(1);
+                        }
+                    };
+                    addr.set_port(next);
+                }
+                Err(e) => {
+                    serr!("failed to bind TCP listener: {e}");
+                    std::process::exit(1);
+                }
+            }
+        }
+    };
+
     slog!(
         "[spiceio] connecting to smb://****@{}:{}/{} ({}x)",
         config.smb_server,
@@ -128,13 +154,6 @@ async fn main() {
         multipart: MultipartStore::new(),
     });
 
-    let bind_addr = config.bind_addr;
-
-    // Bind TCP listener
-    let listener = TcpListener::bind(bind_addr)
-        .await
-        .expect("failed to bind TCP listener");
-
     slog!("[spiceio] listening on http://{bind_addr}");
     slog!(
         "[spiceio] bucket: {} region: {}",

src/s3/router.rs

@@ -1402,7 +1402,12 @@ fn with_common_headers(
     }
     headers.insert(X_AMZ_ID_2, request_id.parse().unwrap());
     headers.insert(X_AMZ_BUCKET_REGION, region.parse().unwrap());
-    headers.insert("Server", "spiceio".parse().unwrap());
+    headers.insert(
+        "Server",
+        concat!("spiceio/", env!("CARGO_PKG_VERSION"))
+            .parse()
+            .unwrap(),
+    );
     // CORS allow
     if !headers.contains_key("access-control-allow-origin") {
         headers.insert("Access-Control-Allow-Origin", "*".parse().unwrap());