feat: file logging on client, logs command to fetch last N lines

crates/client/src/logger.rs

@@ -0,0 +1,59 @@
+/// File logger — writes structured log lines alongside the pretty terminal output.
+use std::fs::{File, OpenOptions};
+use std::io::Write;
+use std::sync::{Mutex, OnceLock};
+
+static LOG_FILE: OnceLock<Mutex<File>> = OnceLock::new();
+static LOG_PATH: OnceLock<String> = OnceLock::new();
+
+pub fn init() {
+    let path = log_path();
+    // Create parent dir if needed
+    if let Some(parent) = std::path::Path::new(&path).parent() {
+        let _ = std::fs::create_dir_all(parent);
+    }
+    match OpenOptions::new().create(true).append(true).open(&path) {
+        Ok(f) => {
+            LOG_PATH.set(path.clone()).ok();
+            LOG_FILE.set(Mutex::new(f)).ok();
+            write_line("INFO", "helios-remote started");
+        }
+        Err(e) => eprintln!("[logger] Failed to open log file {path}: {e}"),
+    }
+}
+
+fn log_path() -> String {
+    #[cfg(windows)]
+    {
+        let base = std::env::var("LOCALAPPDATA")
+            .unwrap_or_else(|_| "C:\\Temp".to_string());
+        format!("{base}\\helios-remote\\helios-remote.log")
+    }
+    #[cfg(not(windows))]
+    {
+        "/tmp/helios-remote.log".to_string()
+    }
+}
+
+pub fn get_log_path() -> String {
+    LOG_PATH.get().cloned().unwrap_or_else(log_path)
+}
+
+pub fn write_line(level: &str, msg: &str) {
+    let now = chrono::Local::now().format("%Y-%m-%d %H:%M:%S");
+    let line = format!("{now} [{level:<5}] {msg}\n");
+    if let Some(mutex) = LOG_FILE.get() {
+        if let Ok(mut f) = mutex.lock() {
+            let _ = f.write_all(line.as_bytes());
+        }
+    }
+}
+
+/// Read the last `n` lines from the log file.
+pub fn tail(n: u32) -> String {
+    let path = get_log_path();
+    let content = std::fs::read_to_string(&path).unwrap_or_default();
+    let lines: Vec<&str> = content.lines().collect();
+    let start = lines.len().saturating_sub(n as usize);
+    lines[start..].join("\n")
+}

crates/client/src/main.rs

@@ -13,6 +13,7 @@ use base64::Engine;
 use helios_common::{ClientMessage, ServerMessage};
 use uuid::Uuid;
 
+mod logger;
 mod shell;
 mod screenshot;
 mod input;
@@ -76,21 +77,27 @@ macro_rules! log_status {
 }
 
 macro_rules! log_ok {
-    ($($arg:tt)*) => {
-        println!("  {}\t{}", "✅", format!($($arg)*));
-    };
+    ($($arg:tt)*) => {{
+        let msg = format!($($arg)*);
+        println!("  {}\t{}", "✅", msg);
+        logger::write_line("OK", &msg);
+    }};
 }
 
 macro_rules! log_err {
-    ($($arg:tt)*) => {
-        println!("  {}\t{}", "❌", format!($($arg)*));
-    };
+    ($($arg:tt)*) => {{
+        let msg = format!($($arg)*);
+        println!("  {}\t{}", "❌", msg);
+        logger::write_line("ERROR", &msg);
+    }};
 }
 
 macro_rules! log_cmd {
-    ($emoji:expr, $($arg:tt)*) => {
-        println!("  {}\t{}", $emoji, format!($($arg)*));
-    };
+    ($emoji:expr, $($arg:tt)*) => {{
+        let msg = format!($($arg)*);
+        println!("  {}\t{}", $emoji, msg);
+        logger::write_line("CMD", &msg);
+    }};
 }
 
 // ────────────────────────────────────────────────────────────────────────────
@@ -173,6 +180,7 @@ async fn main() {
     // Enable ANSI color codes on Windows (required when running as admin)
     #[cfg(windows)]
     enable_ansi();
+    logger::init();
 
     // Suppress tracing output by default
     if std::env::var("RUST_LOG").is_err() {
@@ -558,6 +566,13 @@ async fn handle_message(
             }
         }
 
+        ServerMessage::LogsRequest { request_id, lines } => {
+            log_cmd!("📜", "logs (last {lines} lines)");
+            let content = logger::tail(lines);
+            let log_path = logger::get_log_path();
+            ClientMessage::LogsResponse { request_id, content, log_path }
+        }
+
         ServerMessage::UploadRequest { request_id, path, content_base64 } => {
             log_cmd!("⬆ ", "upload → {}", path);
             match (|| -> Result<(), String> {

crates/common/src/protocol.rs

@@ -17,6 +17,8 @@ pub enum ServerMessage {
     ScreenshotRequest { request_id: Uuid },
     /// Capture a specific window by its HWND (works even if behind other windows)
     WindowScreenshotRequest { request_id: Uuid, window_id: u64 },
+    /// Fetch the last N lines of the client log file
+    LogsRequest { request_id: Uuid, lines: u32 },
     /// Show a MessageBox on the client asking the user to do something.
     /// Blocks until the user clicks OK — use this when you need the user
     /// to perform a manual action before continuing.
@@ -122,6 +124,11 @@ pub enum ClientMessage {
         version: String,
         commit: String,
     },
+    LogsResponse {
+        request_id: Uuid,
+        content: String,
+        log_path: String,
+    },
     /// Response to a download request
     DownloadResponse {
         request_id: Uuid,

crates/server/src/api.rs

@@ -135,6 +135,29 @@ pub async fn window_screenshot(
     }
 }
 
+/// GET /sessions/:id/logs?lines=100
+pub async fn logs(
+    Path(session_id): Path<String>,
+    Query(params): Query<std::collections::HashMap<String, String>>,
+    State(state): State<AppState>,
+) -> impl IntoResponse {
+    let lines: u32 = params.get("lines").and_then(|v| v.parse().ok()).unwrap_or(100);
+    match dispatch(&state, &session_id, "logs", |rid| {
+        ServerMessage::LogsRequest { request_id: rid, lines }
+    }).await {
+        Ok(ClientMessage::LogsResponse { content, log_path, .. }) => (
+            StatusCode::OK,
+            Json(serde_json::json!({ "content": content, "log_path": log_path, "lines": lines })),
+        ).into_response(),
+        Ok(ClientMessage::Error { message, .. }) => (
+            StatusCode::INTERNAL_SERVER_ERROR,
+            Json(serde_json::json!({ "error": message })),
+        ).into_response(),
+        Ok(_) => (StatusCode::BAD_GATEWAY, Json(serde_json::json!({ "error": "Unexpected response" }))).into_response(),
+        Err(e) => e.into_response(),
+    }
+}
+
 /// POST /sessions/:id/screenshot
 pub async fn request_screenshot(
     Path(session_id): Path<String>,

crates/server/src/main.rs

@@ -54,6 +54,7 @@ async fn main() -> anyhow::Result<()> {
         .route("/sessions/:id/prompt", post(api::prompt_user))
         .route("/sessions/:id/windows", get(api::list_windows))
         .route("/sessions/:id/windows/minimize-all", post(api::minimize_all))
+        .route("/sessions/:id/logs", get(api::logs))
         .route("/sessions/:id/windows/:window_id/screenshot", post(api::window_screenshot))
         .route("/sessions/:id/windows/:window_id/focus", post(api::focus_window))
         .route("/sessions/:id/windows/:window_id/maximize", post(api::maximize_and_focus))

skills/remote.py

@@ -236,6 +236,17 @@ def cmd_maximize(args):
     print(f"Window {wid} maximized on session {sid!r}.")
 
 
+def cmd_logs(args):
+    """Fetch the last N lines of the client log file."""
+    sid = resolve_session(args.session_id)
+    resp = _req("GET", f"/sessions/{sid}/logs", params={"lines": args.lines})
+    data = resp.json()
+    if "error" in data:
+        sys.exit(f"[helios-remote] {data['error']}")
+    print(f"# {data.get('log_path', '?')}  (last {args.lines} lines)")
+    print(data.get("content", ""))
+
+
 def cmd_screenshot_window(args):
     """Capture a specific window by ID or title substring → /tmp/helios-remote-screenshot.png"""
     sid = resolve_session(args.session_id)
@@ -484,6 +495,10 @@ def build_parser() -> argparse.ArgumentParser:
     stp = sub.add_parser("status", help="Show relay + client commit and sync status")
     stp.add_argument("session_id")
 
+    lgp = sub.add_parser("logs", help="Fetch last N lines of client log file")
+    lgp.add_argument("session_id")
+    lgp.add_argument("--lines", type=int, default=100, metavar="N", help="Number of lines (default: 100)")
+
     sub.add_parser("server-version", help="Get server version (no auth required)")
 
     vp = sub.add_parser("version", help="Get client version for a session")
@@ -550,6 +565,7 @@ def main():
         "upload":         cmd_upload,
         "download":       cmd_download,
         "status":            cmd_status,
+        "logs":              cmd_logs,
         "screenshot-window": cmd_screenshot_window,
         "find-window":      cmd_find_window,
         "wait-for-window":  cmd_wait_for_window,