Get all possible filters from backend

backend/server.js

@@ -32,6 +32,12 @@ async function run() {
   changeStream = collection.watch(pipeline, options);
   console.log("Started watching changes in database");
 
+  const filterOptions = {
+    'kubernetes.namespace': await collection.distinct('kubernetes.namespace'),
+    'kubernetes.pod.name': await collection.distinct('kubernetes.pod.name'),
+    'kubernetes.container.name': await collection.distinct('kubernetes.container.name')
+  }
+
   const writeMessage = (response, blob) => {
     const id = blob._id || null
     const message = `id: ${id}\nevent: message\ndata: ${JSON.stringify(blob)}\n\n`
@@ -45,6 +51,9 @@ async function run() {
     const header = { 'Content-Type': 'text/event-stream', 'Connection': 'keep-alive' };
     response.writeHead(200, "OK", header);
 
+    const message = `id: 1\nevent: filters\ndata: ${JSON.stringify(filterOptions)}\n\n`
+    response.write(message)
+
     const historyCursor = collection.find()
         .sort({$natural:-1})
         .limit(historyNumber).toArray().then((res) => {

frontend/src/components/LogViewer.vue

@@ -44,6 +44,7 @@ export default {
         enableCellChangeFlash: true
       },
       currentRowCount: 0,
+      comboBoxOptions: {},
       viewRowCount: 20,
       comboBoxOptions: [],
       columnDefs:  [
@@ -88,6 +89,7 @@ export default {
     setupStream() {
       let es = new EventSource('/events');
       es.onmessage = (e) => this.handleReceiveMessage(e)
+      es.addEventListener("filters", (e) => this.handleReceiveFilters(e))
     },
     onGridReady(params) {
       this.gridApi = params.api;
@@ -102,6 +104,9 @@ export default {
       this.gridApi.flashCells({ rowNodes: [rowNode]});
       this.gridApi.sizeColumnsToFit()
     },
+    handleReceiveFilters (event) {
+      this.comboBoxOptions = this.parseEventData(event.data);
+    },
     parseEventData (eventData) {
       try {
         let json = JSON.parse(eventData)