feat: admin terminal - show connected instance

backend/controllers/terminal.ts

@@ -5,9 +5,9 @@ import type { WebSocket } from 'ws'
  * _terminal Routes
  *
  * The websocket behind the admin area's terminal view, which streams this instance's log lines to a
- * browser as they are written. Read-only: nothing a client sends is looked at, and the socket carries
+ * browser as they are written. Read-only: nothing a client sends is looked at, and every frame after
- * exactly what `core/logger.ts` hands to `console.log`, formatted string and all — including the ANSI
+ * the first is exactly what `core/logger.ts` hands to `console.log`, formatted string and all —
- * colours, which xterm renders.
+ * including the ANSI colours, which xterm renders. The first frame is the handshake below.
  *
  * Only this instance's own main thread is on that stream. Worker threads build their own logger
  * (`worker.ts`), and other instances write to their own consoles, so a clustered deployment shows the
@@ -43,6 +43,15 @@ async function routes(app: FastifyInstance) {
         return socket.close(4403, 'You are not allowed to read the server logs')
       }
 
+      const user = req.session.user?.email ?? req.session.user?.id ?? 'unknown'
+
+      /*
+        Logged before the listener is attached, so the line is already in the backlog by the time it
+        is replayed below and the terminal opens on its own arrival. Every other connected terminal
+        sees it live, which is the point: who is reading the logs is itself worth logging.
+      */
+      WIKI.logger.info(`Streaming server logs to user ${user}... [ CONNECTED ]`)
+
       const send = (line: string) => {
         if (socket.readyState !== socket.OPEN || socket.bufferedAmount > MAX_BUFFERED) {
           return
@@ -50,6 +59,14 @@ async function routes(app: FastifyInstance) {
         socket.send(line)
       }
 
+      /*
+        The handshake, and the only frame that is not a log line: which instance the client ended up
+        talking to, since in a cluster that is the one thing the logs themselves cannot tell it — a
+        line names the instance that WROTE it, and the backlog replayed below was written by this one.
+        Sent before anything else, so "the first frame" is all the client has to know to find it.
+      */
+      socket.send(JSON.stringify({ instance: WIKI.INSTANCE_ID }))
+
       // -> A terminal that opens onto an idle server would otherwise sit empty and look broken
       for (const line of WIKI.logger.backlog()) {
         send(line)
@@ -57,7 +74,12 @@ async function routes(app: FastifyInstance) {
 
       WIKI.logger.ws.on('log', send)
       socket.on('close', () => {
+        // -> Off the stream first, so this instance's own goodbye is not sent down a socket that is
+        //    already closing
         WIKI.logger.ws.off('log', send)
+        WIKI.logger.info(
+          `User ${user} has disconnected from server logs streaming. [ DISCONNECTED ]`
+        )
       })
     }
   )

backend/locales/en.json

@@ -1026,8 +1026,9 @@
   "admin.terminal.connecting": "Connecting to server...",
   "admin.terminal.disconnect": "Disconnect",
   "admin.terminal.disconnected": "Disconnected.",
+  "admin.terminal.instance": "Connected to instance",
   "admin.terminal.logs": "Logs",
-  "admin.terminal.subtitle": "View process logs in real-time",
+  "admin.terminal.subtitle": "View server logs in real-time",
   "admin.terminal.title": "Terminal",
   "admin.theme.accentColor": "Accent Color",
   "admin.theme.accentColorHint": "The accent color for elements that need to stand out or grab the user attention.",

frontend/src/pages/AdminTerminal.vue

@@ -12,7 +12,14 @@
           {{ t('admin.terminal.subtitle') }}
         </div>
       </div>
-      <div class="flex-none flex">
+      <div class="flex-none flex items-center">
+        <div v-if="state.connected" class="mr-4 text-right leading-tight">
+          <div class="text-xs text-grey">{{ t('admin.terminal.instance') }}</div>
+          <div class="flex items-center justify-end gap-1.5 font-mono text-sm">
+            <status-light class="admin-terminal-dot" color="positive" pulse />
+            {{ state.instance }}
+          </div>
+        </div>
         <w-btn
           class="acrylic-btn mr-2"
           v-if="!state.connected || state.connecting"
@@ -89,7 +96,9 @@ useMeta({
 const state = reactive({
   displayMode: 'logs',
   connected: false,
-  connecting: false
+  connecting: false,
+  /** Which instance is on the other end of the socket, from its handshake frame. */
+  instance: null
 })
 
 let socket = null
@@ -120,6 +129,7 @@ function connect() {
   // -> Whether the stream ever started is what tells a session that was refused or never reached the
   //    server apart from one that ran and ended, and only `close` is guaranteed to fire
   let opened = false
+  let handshake = false
 
   socket.addEventListener('open', () => {
     opened = true
@@ -129,6 +139,15 @@ function connect() {
   })
 
   socket.addEventListener('message', (ev) => {
+    /*
+      The server's first frame is the handshake and says which instance answered; everything after it
+      is a log line to be printed verbatim. See `controllers/terminal.ts`.
+    */
+    if (!handshake) {
+      handshake = true
+      state.instance = JSON.parse(ev.data).instance
+      return
+    }
     term.writeln(ev.data)
   })
 
@@ -136,6 +155,7 @@ function connect() {
     socket = null
     state.connected = false
     state.connecting = false
+    state.instance = null
     /*
       Codes in the 4000 range are the server's own (see `controllers/terminal.ts`) and mean the
       session was refused rather than dropped, so the reason is worth printing — reconnecting with the
@@ -194,6 +214,14 @@ onBeforeUnmount(() => {
 
 <style lang="scss">
 .admin-terminal {
+  /* -> `status-light` is a bar sized by whatever it sits in; here it wants to be a dot */
+  &-dot {
+    width: 6px;
+    height: 6px;
+    min-height: 6px;
+    flex: none;
+  }
+
   &-term {
     width: 100%;
     /* -> The terminal fits itself to this box, so the box has to have a height of its own: sized off