A bit more error handling.

Seeing if we can consistently inform the frontend about request errors.
Also, trying to outright crash with slightly less frequency.

app.js

@@ -24,12 +24,13 @@ const buildCluster = (clusterConfig, connect = true) => {
 
   const kafka = new Kafka(kafkaConfig)
   const admin = kafka.admin()
-  admin.connect().catch(console.error)
-  return c({
+  const cluster = {
     kafka,
     admin,
     config: clusterConfig
-  })
+  }
+  admin.connect().catch(e => console.error(cluster.error = e.toString()))
+  return cluster
 }
 
 const clusters =
@@ -50,15 +51,19 @@ app.use(express.static(path.join(__dirname, 'public')));
 
 const router = express.Router()
 
+process.on('unhandledRejection', console.error)
+
 /* GET topics listing. */
 router.get('/topics/:cluster', async (req, res, _next) => {
   const legalName = topicName => !topicName.startsWith("__")
-  const topicList = await clusters[req.params.cluster]?.admin.listTopics()
-  if (topicList) {
+  try {
+    const topicList = (await clusters[req.params.cluster]?.admin.listTopics() || [])
     res.send(topicList.filter(legalName))
-  } else {
-    res.send([])
-    //res.status(400).send({error: 'Invalid cluster name'})
+  } catch (e) {
+    res.status(502).send({
+      error: `Could not connect to cluster '${req.params.cluster}'`,
+      errorDetails: e.toString()
+    })
   }
 })
 
@@ -75,6 +80,7 @@ const getClusterData = () =>
     }))
 
 router.get('/clusters', async (req, res, _next) => {
+  console.log('/clusters')
   res.send(getClusterData())
 })
 
@@ -88,7 +94,6 @@ router.post('/clusters', async (req, res, _next) => {
 })
 
 router.post('/clusters/delete', async (req, res, _next) => {
-  console.log('/clusters/delete post body', req.body)
   const clusterName = req.body.clusterName
   // TODO: Disconnect
   delete clusters[clusterName]
@@ -98,10 +103,7 @@ router.post('/clusters/delete', async (req, res, _next) => {
 })
 
 router.put('/clusters', async (req, res, _next) => {
-  console.log('/clusters put body', req.body)
-
   const hasPlaceholderPassword = req.body.sasl.password === passwordPlaceholder
-  console.log('Has placeholder password:', hasPlaceholderPassword)
   const clusterName = req.body.clusterName
   if (hasPlaceholderPassword) {
     req.body.password = config.clusters[clusterName].password
@@ -167,14 +169,12 @@ wsServer.on('connection', socket => {
   })
 
   socket.on('message', async message => {
-    socket.send('Loading...')
+    console.log('socket message')
+    //socket.send('Loading...')
     message = JSON.parse(message)
 
     const currentMode = message.mode === 'realTime' ? realTimeSearch : search
-    console.log('CLUSTERS before run', clusters)
-    console.log('message.cluster', message.cluster)
     const cluster = clusters[message.cluster]
-    console.log('clusters[message.cluster]', cluster)
     const run = async () => consumers.set(socket, await currentMode({
       kafka: cluster.kafka,
       searchCode: message.searchCode,