server: timeout mechanism

Signed-off-by: Francis Bouvier <francis@lightpanda.io>

src/server.zig

@@ -34,6 +34,9 @@ const NoError = error{NoError};
 const IOError = AcceptError || RecvError || SendError || CloseError || TimeoutError;
 const Error = IOError || std.fmt.ParseIntError || cdp.Error || NoError;
 
+const TimeoutCheck = std.time.ns_per_ms * 100;
+const TimeoutRead = std.time.ns_per_s * 3;
+
 // I/O Recv
 // --------
 
@@ -48,19 +51,28 @@ pub const Cmd = struct {
     buf: []u8, // only for read operations
     err: ?Error = null,
 
-    completion: *Completion,
-    acceptCtx: *Accept = undefined,
-
     msg_buf: *MsgBuffer,
 
+    // I/O fields
+    read_completion: *Completion,
+    timeout_completion: *Completion,
+    acceptCtx: *Accept = undefined,
+    last_active: ?std.time.Instant = null,
+
     // CDP
     state: cdp.State = .{},
 
     // JS fields
     browser: *Browser, // TODO: is pointer mandatory here?
+    sessionNew: bool,
     // try_catch: public.TryCatch, // TODO
 
-    fn cbk(self: *Cmd, completion: *Completion, result: RecvError!usize) void {
+    // callbacks
+    // ---------
+
+    fn readCbk(self: *Cmd, completion: *Completion, result: RecvError!usize) void {
+        std.debug.assert(completion == self.read_completion);
+
         const size = result catch |err| {
             self.err = err;
             return;
@@ -68,7 +80,7 @@ pub const Cmd = struct {
 
         if (size == 0) {
             // continue receving incomming messages asynchronously
-            self.loop.io.recv(*Cmd, self, cbk, completion, self.socket, self.buf);
+            self.loop.io.recv(*Cmd, self, Cmd.readCbk, self.read_completion, self.socket, self.buf);
             return;
         }
 
@@ -79,12 +91,6 @@ pub const Cmd = struct {
             std.debug.print("\ninput size: {d}, content: {s}\n", .{ size, content });
         }
 
-        // close on exit command
-        if (std.mem.eql(u8, input, "exit")) {
-            self.err = error.NoError;
-            return;
-        }
-
         // read and execute input
         self.msg_buf.read(self.alloc(), input, self, Cmd.do) catch |err| {
             if (err != error.Closed) {
@@ -93,16 +99,93 @@ pub const Cmd = struct {
             return;
         };
 
+        // set connection timestamp
+        self.last_active = std.time.Instant.now() catch |err| {
+            std.log.err("read timestamp error: {any}", .{err});
+            return;
+        };
+
         // continue receving incomming messages asynchronously
-        self.loop.io.recv(*Cmd, self, cbk, completion, self.socket, self.buf);
+        self.loop.io.recv(*Cmd, self, Cmd.readCbk, self.read_completion, self.socket, self.buf);
+    }
+
+    fn timeoutCbk(self: *Cmd, completion: *Completion, result: TimeoutError!void) void {
+        std.debug.assert(completion == self.timeout_completion);
+
+        _ = result catch |err| {
+            self.err = err;
+            return;
+        };
+
+        if (self.isClosed()) {
+            // conn is already closed, ignore timeout
+            return;
+        }
+
+        // check time since last read
+        const now = std.time.Instant.now() catch |err| {
+            std.log.err("timeout timestamp error: {any}", .{err});
+            return;
+        };
+
+        if (now.since(self.last_active.?) > TimeoutRead) {
+            // closing
+            std.log.debug("conn timeout, closing...", .{});
+
+            // NOTE: we should cancel the current read
+            // but it seems that's just closing the connection is enough
+            // (and cancel does not work on MacOS)
+
+            // close current connection
+            self.loop.io.close(*Cmd, self, Cmd.closeCbk, self.timeout_completion, self.socket);
+            return;
+        }
+
+        // continue checking timeout
+        self.loop.io.timeout(*Cmd, self, Cmd.timeoutCbk, self.timeout_completion, TimeoutCheck);
+    }
+
+    fn closeCbk(self: *Cmd, completion: *Completion, result: CloseError!void) void {
+        _ = completion;
+        // NOTE: completion can be either self.completion or self.timeout_completion
+
+        _ = result catch |err| {
+            self.err = err;
+            return;
+        };
+
+        // conn is closed
+        self.last_active = null;
+
+        // restart a new browser session in case of re-connect
+        if (!self.sessionNew) {
+            self.newSession() catch |err| {
+                std.log.err("new session error: {any}", .{err});
+                return;
+            };
+        }
+
+        std.log.debug("conn closed", .{});
+        std.log.debug("accepting new conn...", .{});
+
+        // continue accepting incoming requests
+        self.loop.io.accept(*Accept, self.acceptCtx, Accept.cbk, self.read_completion, self.acceptCtx.socket);
     }
 
     // shortcuts
+    // ---------
+
+    inline fn isClosed(self: *Cmd) bool {
+        // last_active is first saved on acceptCbk
+        return self.last_active == null;
+    }
+
+    // allocator of the current session
     inline fn alloc(self: *Cmd) std.mem.Allocator {
-        // TODO: should we return the allocator from the page instead?
         return self.browser.currentSession().alloc;
     }
 
+    // JS env of the current session
     inline fn env(self: Cmd) public.Env {
         return self.browser.currentSession().env;
     }
@@ -114,14 +197,19 @@ pub const Cmd = struct {
 
         // close cmd
         if (std.mem.eql(u8, cmd, "close")) {
-            self.loop.io.close(*Cmd, self, Cmd.closeCbk, self.completion, self.socket);
+            // close connection
+            std.log.debug("close cmd, closing...", .{});
+            self.loop.io.close(*Cmd, self, Cmd.closeCbk, self.read_completion, self.socket);
             return error.Closed;
         }
 
-        // cdp cmd
+        if (self.sessionNew) self.sessionNew = false;
+
+        // cdp end cmd
         const res = cdp.do(self.alloc(), cmd, self) catch |err| {
-            // cdp end
             if (err == error.DisposeBrowserContext) {
+                // restart a new browser session
+                std.log.debug("cdp end cmd", .{});
                 try self.newSession();
                 return;
             }
@@ -136,24 +224,15 @@ pub const Cmd = struct {
     }
 
     fn newSession(self: *Cmd) !void {
-        std.log.info("new session", .{});
         try self.browser.newSession(self.alloc(), self.loop);
         const cmd_opaque = @as(*anyopaque, @ptrCast(self));
         try self.browser.currentSession().setInspector(cmd_opaque, Cmd.onInspectorResp, Cmd.onInspectorNotif);
+        self.sessionNew = true;
+        std.log.debug("new session", .{});
     }
 
-    fn closeCbk(self: *Cmd, completion: *Completion, result: CloseError!void) void {
+    // inspector
-        _ = result catch |err| {
+    // ---------
-            self.err = err;
-            return;
-        };
-        std.log.debug("conn closed", .{});
-
-        // continue accepting incoming requests
-        self.loop.io.accept(*Accept, self.acceptCtx, Accept.cbk, completion, self.acceptCtx.socket);
-    }
-
-    // Inspector
 
     pub fn sendInspector(self: *Cmd, msg: []const u8) void {
         if (self.env().getInspector()) |inspector| {
@@ -271,13 +350,22 @@ const Accept = struct {
     socket: std.posix.socket_t,
 
     fn cbk(self: *Accept, completion: *Completion, result: AcceptError!std.posix.socket_t) void {
+        std.debug.assert(completion == self.cmd.read_completion);
+
         self.cmd.socket = result catch |err| {
             self.cmd.err = err;
             return;
         };
 
+        // set connection timestamp and timeout
+        self.cmd.last_active = std.time.Instant.now() catch |err| {
+            std.log.err("accept timestamp error: {any}", .{err});
+            return;
+        };
+        self.cmd.loop.io.timeout(*Cmd, self.cmd, Cmd.timeoutCbk, self.cmd.timeout_completion, TimeoutCheck);
+
         // receving incomming messages asynchronously
-        self.cmd.loop.io.recv(*Cmd, self.cmd, Cmd.cbk, completion, self.cmd.socket, self.cmd.buf);
+        self.cmd.loop.io.recv(*Cmd, self.cmd, Cmd.readCbk, self.cmd.read_completion, self.cmd.socket, self.cmd.buf);
     }
 };
 
@@ -290,17 +378,22 @@ pub fn listen(browser: *Browser, loop: *public.Loop, socket: std.posix.socket_t)
     var msg_buf = try MsgBuffer.init(loop.alloc, BufReadSize * 256); // 256KB
     defer msg_buf.deinit(loop.alloc);
 
+    // create I/O completions
+    var completion: Completion = undefined;
+    var timeout_completion: Completion = undefined;
+
     // create I/O contexts and callbacks
     // for accepting connections and receving messages
     var ctxInput: [BufReadSize]u8 = undefined;
-    var completion: Completion = undefined;
     var cmd = Cmd{
         .loop = loop,
         .browser = browser,
+        .sessionNew = true,
         .socket = undefined,
         .buf = &ctxInput,
         .msg_buf = &msg_buf,
-        .completion = &completion,
+        .read_completion = &completion,
+        .timeout_completion = &timeout_completion,
     };
     const cmd_opaque = @as(*anyopaque, @ptrCast(&cmd));
     try browser.currentSession().setInspector(cmd_opaque, Cmd.onInspectorResp, Cmd.onInspectorNotif);
@@ -312,6 +405,7 @@ pub fn listen(browser: *Browser, loop: *public.Loop, socket: std.posix.socket_t)
     cmd.acceptCtx = &accept;
 
     // accepting connection asynchronously on internal server
+    std.log.debug("accepting new conn...", .{});
     loop.io.accept(*Accept, &accept, Accept.cbk, &completion, socket);
 
     // infinite loop on I/O events, either: