Add .json extension to config file.

A tiny bit of refactoring.

app.js

@@ -13,23 +13,31 @@ const { buildEscape } = require('./safely-exit')
 const config = readConfig()
 console.log('CONFIG', config)
 
-const c = object => {
-  console.log(object)
-  return object
+/**
+ * Log out an object and return it.
+ *
+ * @param object The object to log
+ * @param f Optional param to specify an alternative log function. E.g. console.error
+ * @returns {*}
+ */
+const c = (object, f = console.log) => {
+  f(object)
+  return object;
 }
 
 const buildCluster = (clusterConfig, connect = true) => {
   const kafkaConfig = {...clusterConfig}
-  delete kafkaConfig.clusterName
+  delete kafkaConfig.clusterName // new Kafka() tries to use this same value
 
   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 =
@@ -40,7 +48,7 @@ console.log('CLUSTERS', clusters)
 const app = express();
 
 app.use(cors({
-  origin: 'http://localhost:5173'
+  origin: config.frontendUrl,
 }))
 app.use(logger('dev'));
 app.use(express.json());
@@ -50,29 +58,45 @@ 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()
+    })
   }
 })
 
+const buildSocketMessageSender = ({ type, socket }) => message => {
+  socket.send(JSON.stringify({
+    type,
+    message
+  }))
+}
+
+const deepCopy = object => JSON.parse(JSON.stringify(object))
+
 const passwordPlaceholder = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXX'
 
 const getClusterData = () =>
   Object.fromEntries(
-    Object.entries(clusters).map(([key, value]) => {
-      value = JSON.parse(JSON.stringify(value))
-      value.config.sasl.password = passwordPlaceholder
-      return [key, value.config]
+    Object.entries(clusters).map(([key, cluster]) => {
+      cluster = deepCopy(cluster)
+      if (cluster.config.sasl?.password) {
+        cluster.config.sasl.password = passwordPlaceholder
+      }
+      return [key, cluster.config]
     }))
 
 router.get('/clusters', async (req, res, _next) => {
+  console.log('/clusters')
   res.send(getClusterData())
 })
 
@@ -86,9 +110,17 @@ 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
+  // Kill all consumers connected to this cluster and notify those clients via their websocket
+  consumers.forEach(([{ consumer, cluster }, socket]) => {
+    if (clusters[clusterName] !== cluster) {
+      // TODO This reference equality may not be sufficient?
+      return
+    }
+    killConsumer(consumer)
+    const sendDeletedMessage = buildSocketMessageSender({ type: 'cluster_deleted', socket })
+    sendDeletedMessage(clusterName)
+  })
   delete clusters[clusterName]
   delete config.clusters[clusterName]
   await storeConfig(config)
@@ -96,10 +128,7 @@ 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
@@ -107,83 +136,72 @@ router.put('/clusters', async (req, res, _next) => {
   config.clusters[clusterName] = req.body
   clusters[clusterName] = buildCluster(req.body)
   res.send('')
-  //res.send(getClusterData())
   await storeConfig(config)
 })
 
 app.use(router)
 
-const realTimeSearch = async ({ kafka, searchCode, immutable, socket, topic }) =>
+const realTimeSearch = async ({ kafka, socket, topic }) =>
   query.realTimeMessageSearch({
     kafka,
     topic,
-    searchCode,
-    immutable,
-    onMessage: message => {
-      socket.send(JSON.stringify({
-        type: 'message',
-        message
-      }))
-    }
-  })
+    onMessage: buildSocketMessageSender({ socket, type: 'message' })
+  });
 
-const search = async ({ kafka, searchCode, immutable, socket, topic, maxItems }) =>
+const oneShotSearch = async ({ kafka, socket, topic, maxItems }) =>
   query.searchMessages({
     kafka,
     topic,
     maxItems,
-    searchCode,
-    immutable,
-    onDone: messages => {
-      console.log(messages.length + ' messages')
-      socket.send(JSON.stringify({
-        type: 'complete',
-        message: messages
-      }))
-    },
-    onBatchDone: count => {
-      socket.send(JSON.stringify({
-        type: 'item_count',
-        message: count
-      }))
-    }
+    onDone: buildSocketMessageSender({ socket, type: 'count' }),
+    onBatchDone: buildSocketMessageSender({ socket, type: 'item_count' })
   })
 
+/** @type {WebSocketServer} */
 const wsServer = new ws.WebSocketServer({
   noServer: true
 })
 
+/** @type {Map<WebSocket, ({consumer: kafka.Consumer, cluster: { kafka, admin, config }})>} */
 const consumers = new Map()
 
 buildEscape(consumers, clusters)
 
 wsServer.on('connection', socket => {
+  socket.send('CONNECTED')
   socket.on('close', async () => {
-    await killConsumer(consumers.get(socket))
+    await killConsumer(consumers.get(socket).consumer)
     consumers.delete(socket)
   })
 
   socket.on('message', async 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)
+    if (message.mode === 'kill') {
+      console.log('KILLING SOCKET')
+      await killConsumer(consumers.get(socket).consumer)
+      consumers.delete(socket)
+      return
+    }
+    const startSearch = message.mode === 'realTime' ? realTimeSearch : oneShotSearch
     const cluster = clusters[message.cluster]
-    console.log('clusters[message.cluster]', cluster)
-    const run = async () => consumers.set(socket, await currentMode({
+
+    const run = async () => {
+      const consumerCluster = {
+        consumer: await startSearch({
           kafka: cluster.kafka,
-      searchCode: message.searchCode,
-      immutable: message.immutable,
           topic: message.topic,
           maxItems: message.maxItems,
           socket
-    }))
+        }),
+        cluster
+      }
+      consumers.set(socket, consumerCluster);
+    }
 
     run().catch(async e => {
       console.error('run() error occurred!', e.toString())
-      await killConsumer(consumers.get(socket))
+      await killConsumer(consumers.get(socket).consumer)
       // Try again ONCE on failure
       run().catch(ee => socket.send('ERROR: ' + ee))
     })

config.js

@@ -2,23 +2,23 @@ const fs = require('fs')
 const path = require('path')
 const homedir = require('os').homedir()
 
-const configFilePath = homedir + path.sep + '.kafka-dance'
+const configFilePath = homedir + path.sep + '.kafka-dance.json'
 
 const emptyConfig = () => ({
-  clusters: {}
+  clusters: {},
+  frontendUrl: 'http://localhost:5173',
 })
 
 const readConfig = () => {
-  if (!fs.existsSync(configFilePath)) {
-    return emptyConfig()
-  }
+  if (fs.existsSync(configFilePath)) {
     try {
       return JSON.parse(fs.readFileSync(configFilePath).toString())
     } catch (e) {
       console.error(e.toString())
-    return emptyConfig()
     }
   }
+  return emptyConfig()
+}
 
 const storeConfig = async config =>
   fs.writeFile(configFilePath, JSON.stringify(config, null, 2), console.error)

query.js

@@ -1,60 +1,55 @@
-const buildMatcher = code => new Function('message', 'value', code)
-
-const deepCopy = obj => JSON.parse(JSON.stringify(obj))
-
-const realTimeMessageSearch = async ({ kafka, topic, onMessage, searchCode, immutable = true }) => {
-  const consumer = kafka.consumer({ groupId: 'sage-testing-group' })
-
-  console.log({ topic, onMessage, searchCode, immutable })
-  await consumer.connect()
-  await consumer.subscribe({ topic, fromBeginning: true })
-  const matcher = searchCode && buildMatcher(searchCode)
-
-  const messages = []
-
-  console.log('consumer.run')
-  await consumer.run({
-    autoCommit: false,
-    eachMessage: async ({ topic, partition, message }) => {
+const parseValue = message => {
   const s = message.value.toString()
-      const value = JSON.parse(s)
-      delete value.Data
-      message.value = value
-      const workingMessage = immutable ? deepCopy(message) : message
-      if (!matcher || matcher(workingMessage, workingMessage.value)) {
-        onMessage(message)
-        messages.push(message)
-        //console.log(message)
+  try {
+    return JSON.parse(s)
+  } catch (e) {
+    console.error('Error deserializing message.value', e) // But keep the value as a string
+    return '' + s
+  }
 }
-    },
-  })
 
-  for (let i = 0; i <= 5; i++) {
-    //console.log(`seek on partition ${i}`)
-    await consumer.seek({topic, partition: i, offset: 0})
-  }
-  console.log('return consumer')
+const buildConsumer = async ({ kafka, topic, fromBeginning }) => {
+  // TODO Use a UUID/GUID instead
+  const consumer = kafka.consumer({ groupId: 'sage-testing-group' + Math.random() })
+
+  await consumer.connect()
+  await consumer.subscribe({ topic, fromBeginning })
+
   return consumer
 }
 
-const searchMessages = async ({ kafka, maxItems, topic, onDone, searchCode, onBatchDone, immutable = true }) => {
-  const consumer = kafka.consumer({ groupId: 'sage-testing-group' })
+const seekToBeginning = async ({ topic, consumer, partitionCount }) => {
+  for (let i = 0; i <= partitionCount; i++) {
+    await consumer.seek({topic, partition: i, offset: 0})
+  }
+}
 
-  await consumer.connect()
-  await consumer.subscribe({ topic, fromBeginning: true })
-  const matcher = searchCode && buildMatcher(searchCode)
+const realTimeMessageSearch = async ({ kafka, topic, onMessage }) => {
+  // TODO Use a UUID/GUID instead
+  const consumer = await buildConsumer({ kafka, topic, fromBeginning: true })
+
+  await consumer.run({
+    autoCommit: false,
+    eachMessage: async ({ topic, partition, message }) => {
+      message.value = parseValue(message.value)
+      onMessage(message)
+    },
+  })
+
+  // seekToBeginning({ topic, consumer, partitionCount: 5 })
+
+  return consumer
+}
+
+const searchMessages = async ({ kafka, maxItems, topic, onDone, onBatchDone }) => {
+  const consumer = await buildConsumer({ kafka, topic, fromBeginning: true })
 
   const messages = []
 
   await consumer.run({
     autoCommit: false,
     eachMessage: async ({ topic, partition, message }) => {
-      const s = message.value.toString()
-      const value = JSON.parse(s)
-      delete value.Data
-      message.value = value
-      let workingMessage = immutable ? deepCopy(message) : message
-      if (!matcher || matcher(workingMessage, workingMessage.value)) {
+      message.value = parseValue(message.value)
       messages.push(message)
       if (messages.length < maxItems) {
         onBatchDone(messages.length)
@@ -64,8 +59,6 @@ const searchMessages = async ({ kafka, maxItems, topic, onDone, searchCode, onBa
         await consumer.disconnect()
         onDone(messages.slice(0, maxItems))
       }
-        //console.log(message)
-      }
     },
   })
 
@@ -88,7 +81,6 @@ const searchMessages = async ({ kafka, maxItems, topic, onDone, searchCode, onBa
    */
   let consumedTopicPartitions = {}
   consumer.on(consumer.events.GROUP_JOIN, async ({ payload }) => {
-    //console.log('GROUP_JOIN')
     const { memberAssignment } = payload
     consumedTopicPartitions = Object.entries(memberAssignment).reduce(
       (topics, [topic, partitions]) => {
@@ -101,6 +93,7 @@ const searchMessages = async ({ kafka, maxItems, topic, onDone, searchCode, onBa
     )
   })
 
+  // This was part of the original code, but seems to cause a near-immediate exit
   /*
    * This is extremely unergonomic, but if we are currently caught up to the head
    * of all topic-partitions, we won't actually get any batches, which means we'll
@@ -114,7 +107,6 @@ const searchMessages = async ({ kafka, maxItems, topic, onDone, searchCode, onBa
   //let processedBatch = true
   consumer.on(consumer.events.FETCH_START, async () => {
     //console.log('FETCH_START')
-    // This was part of the original code, but seems to cause a near-immediate exit
     //if (processedBatch === false) {
     //  console.log('I DIE AT FETCH')
     //  await consumer.disconnect()
@@ -129,7 +121,6 @@ const searchMessages = async ({ kafka, maxItems, topic, onDone, searchCode, onBa
    * and exit if all topic-partitions have been consumed,
    */
   consumer.on(consumer.events.END_BATCH_PROCESS, async ({ payload }) => {
-    //console.log('END_BATCH_PROCESS')
     const { topic, partition, offsetLag } = payload
     consumedTopicPartitions[`${topic}-${partition}`] = offsetLag === '0'
 
@@ -147,10 +138,6 @@ const searchMessages = async ({ kafka, maxItems, topic, onDone, searchCode, onBa
   return consumer
 }
 
-//run()
-//  .then(() => console.log('DONE'))
-//  .catch(e => console.error(`[example/consumer] ${e.message}`, e))
-
 module.exports = {
   searchMessages,
   realTimeMessageSearch,

safely-exit.js

@@ -4,7 +4,7 @@ const signalTraps = ['SIGTERM', 'SIGINT', 'SIGUSR2']
 const disconnectAll = async (consumers, clusters) => {
   await Promise.all([
     ...Object.values(clusters).map(async cluster => cluster.admin.disconnect()),
-    ...Array.from(consumers.values()).map(async consumer => consumer.disconnect())
+    ...Array.from(consumers.values()).map(async consumer => consumer.consumer.disconnect())
   ])
 }