feat: Add real-time log streaming and logging stack configuration

fix: Fix exit signal handle

routes/api/log/realtime.ts

@@ -0,0 +1,66 @@
+import { Handlers } from "$fresh/server.ts";
+import { return_error } from "../../../server/utils.ts";
+import { User, UserPermission } from "../../../db.ts";
+import { base_logger, LogEntry } from "../../../utils/logger.ts";
+import { ExitTarget } from "../../../signal_handler.ts";
+import { toJSON } from "../../../utils.ts";
+
+export type LogRealtimeClientData = { type: "ping" } | { type: "close" } | {
+    type: "pong";
+};
+
+export const handler: Handlers = {
+    GET(req, ctx) {
+        const u = <User | undefined> ctx.state.user;
+        if (
+            u && !u.is_admin &&
+            !(Number(u.permissions) & UserPermission.QueryLog)
+        ) {
+            return return_error(403, "Permission denied.");
+        }
+        const { socket, response } = Deno.upgradeWebSocket(req);
+        const handle = (
+            e: CustomEvent<LogEntry>,
+        ) => {
+            if (socket.readyState === socket.OPEN) {
+                socket.send(toJSON({ type: e.type, detail: e.detail }));
+            }
+        };
+        const close_handle = () => {
+            sendMessage({ type: "close" });
+            socket.close();
+        };
+        const removeListener = () => {
+            base_logger.removeEventListener("new_log", handle);
+            ExitTarget.removeEventListener("close", close_handle);
+        };
+        function sendMessage(mes: { type: string }) {
+            if (socket.readyState === socket.OPEN) {
+                socket.send(toJSON(mes));
+            }
+        }
+        const interval = setInterval(() => {
+            sendMessage({ type: "ping" });
+        }, 30000);
+        socket.onclose = () => {
+            clearInterval(interval);
+            removeListener();
+        };
+        socket.onmessage = (e) => {
+            try {
+                const d: LogRealtimeClientData = JSON.parse(e.data);
+                if (d.type == "close") {
+                    sendMessage({ type: "close" });
+                    socket.close();
+                } else if (d.type == "ping") {
+                    sendMessage({ type: "pong" });
+                }
+            } catch (_) {
+                null;
+            }
+        };
+        base_logger.addEventListener("new_log", handle);
+        ExitTarget.addEventListener("close", close_handle);
+        return response;
+    },
+};