log -f

src/cli/index.ts

@@ -57,7 +57,15 @@ const restartApp = async (app: string) => {
   await post(`/api/apps/${app}/restart`)
 }
 
-async function logApp(name: string) {
+const printLog = (line: LogLine) =>
+  console.log(`${new Date(line.time).toLocaleTimeString()} ${line.text}`)
+
+async function logApp(name: string, options: { follow?: boolean }) {
+  if (options.follow) {
+    await tailLogs(name)
+    return
+  }
+
   const logs: LogLine[] | undefined = await get(`/api/apps/${name}/logs`)
   if (!logs) {
     console.error(`App not found: ${name}`)
@@ -68,8 +76,37 @@ async function logApp(name: string) {
     return
   }
   for (const line of logs) {
-    const time = new Date(line.time).toLocaleTimeString()
-    console.log(`${time} ${line.text}`)
+    printLog(line)
+  }
+}
+
+async function tailLogs(name: string) {
+  const url = join(HOST, `/api/apps/${name}/logs/stream`)
+  const res = await fetch(url)
+  if (!res.ok) {
+    console.error(`App not found: ${name}`)
+    return
+  }
+  if (!res.body) return
+
+  const reader = res.body.getReader()
+  const decoder = new TextDecoder()
+  let buffer = ''
+
+  while (true) {
+    const { done, value } = await reader.read()
+    if (done) break
+
+    buffer += decoder.decode(value, { stream: true })
+    const lines = buffer.split('\n\n')
+    buffer = lines.pop() ?? ''
+
+    for (const line of lines) {
+      if (line.startsWith('data: ')) {
+        const data = JSON.parse(line.slice(6)) as LogLine
+        printLog(data)
+      }
+    }
   }
 }
 
@@ -119,11 +156,13 @@ program
   .command('logs')
   .description('Show logs for an app')
   .argument('<name>', 'app name')
+  .option('-f, --follow', 'follow log output')
   .action(logApp)
 
 program
   .command('log', { hidden: true })
   .argument('<name>', 'app name')
+  .option('-f, --follow', 'follow log output')
   .action(logApp)
 
 program

src/server/index.tsx

@@ -80,6 +80,31 @@ app.get('/api/apps/:app/logs', c => {
   return c.json(app.logs ?? [])
 })
 
+app.sse('/api/apps/:app/logs/stream', (send, c) => {
+  const appName = c.req.param('app')
+  const targetApp = allApps().find(a => a.name === appName)
+  if (!targetApp) return
+
+  let lastLogCount = 0
+
+  const sendNewLogs = () => {
+    const currentApp = allApps().find(a => a.name === appName)
+    if (!currentApp) return
+
+    const logs = currentApp.logs ?? []
+    const newLogs = logs.slice(lastLogCount)
+    lastLogCount = logs.length
+
+    for (const line of newLogs) {
+      send(line)
+    }
+  }
+
+  sendNewLogs()
+  const unsub = onChange(sendNewLogs)
+  return () => unsub()
+})
+
 app.post('/api/apps/:app/start', c => {
   const appName = c.req.param('app')
   if (!appName) return c.json({ error: 'App not found' }, 404)