feat: support PORT env var for listen address

Clap now reads PORT from the environment, accepting either a bare port
number (e.g. 8080 -> 0.0.0.0:8080) or a full host:port. CLI --listen
flag still takes precedence. Deploy Dockerfile defaults PORT=9500 and
removes the hardcoded --listen argument.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker/deploy/Dockerfile

@@ -25,7 +25,8 @@ USER tidal:tidal
 WORKDIR /data
 EXPOSE 9500
 HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
-  CMD curl -sf http://localhost:9500/health || exit 1
+  CMD curl -sf http://localhost:${PORT:-9500}/health || exit 1
 ENV TIDAL_SERVER_LOG=info
+ENV PORT=9500
 ENTRYPOINT ["/usr/local/bin/tidal-server"]
-CMD ["standalone", "--listen", "0.0.0.0:9500", "--schema", "/config/schema.yaml", "--data-dir", "/data"]
+CMD ["standalone", "--schema", "/config/schema.yaml", "--data-dir", "/data"]

tidal-server/Cargo.toml

@@ -11,7 +11,7 @@ path = "src/lib.rs"
 
 [dependencies]
 axum = "0.8"
-clap = { version = "4.5", features = ["derive"] }
+clap = { version = "4.5", features = ["derive", "env"] }
 subtle = "2"
 tower = { version = "0.5", features = ["limit"] }
 tower-http = { version = "0.6", features = ["timeout", "trace", "request-id"] }

tidal-server/src/main.rs

@@ -24,7 +24,7 @@ enum Command {
 
 #[derive(Args)]
 struct StandaloneArgs {
-    #[arg(long, default_value = "127.0.0.1:9400")]
+    #[arg(long, default_value = "127.0.0.1:9400", env = "PORT", value_parser = parse_listen_addr)]
     listen: String,
     #[arg(long)]
     schema: Option<PathBuf>,
@@ -54,6 +54,20 @@ async fn run() -> Result<()> {
     }
 }
 
+/// Parse a listen address from either a full `host:port` string or a bare port number.
+/// When `PORT=8080` is set, clap passes `"8080"` — this normalises it to `0.0.0.0:8080`.
+fn parse_listen_addr(s: &str) -> std::result::Result<String, String> {
+    if s.contains(':') {
+        s.parse::<SocketAddr>()
+            .map(|_| s.to_string())
+            .map_err(|e| format!("invalid address '{s}': {e}"))
+    } else {
+        s.parse::<u16>()
+            .map(|port| format!("0.0.0.0:{port}"))
+            .map_err(|_| format!("expected host:port or port number, got '{s}'"))
+    }
+}
+
 fn init_tracing() {
     let env_filter = std::env::var("TIDAL_SERVER_LOG").unwrap_or_else(|_| "info".into());
     let _ = tracing_subscriber::fmt()