set keepalive header on watch requests

This fix sends keep-alive probes to the server every 30 seconds.

Signed-off-by: Matthew Fisher <matt.fisher@microsoft.com>

package.json

@@ -66,6 +66,7 @@
     "isomorphic-ws": "^4.0.1",
     "js-yaml": "^3.13.1",
     "jsonpath-plus": "^0.19.0",
+    "net-keepalive": "2.0.4",
     "openid-client": "^4.1.1",
     "request": "^2.88.0",
     "rfc4648": "^1.3.0",

src/watch.ts

@@ -1,5 +1,6 @@
 import byline = require('byline');
 import request = require('request');
+import keepalive = require('net-keepalive');
 import { Duplex } from 'stream';
 import { KubeConfig } from './config';
 
@@ -112,6 +113,10 @@ export class Watch {
         req = this.requestImpl.webRequest(requestOptions);
         const stream = byline.createStream();
         req.on('error', doneCallOnce);
+        req.on('socket', function(socket) {
+            socket.setKeepAlive(true);
+            keepalive.setKeepAliveInterval(socket, 30000);
+        });
         stream.on('error', doneCallOnce);
         stream.on('close', () => doneCallOnce(null));
         stream.on('data', (line) => {