Inspect Connection (#784)

Handles `console.log` and `utils.inspect` invocations for a better debugging experience.

`agent` and `ssl` are hidden since they made the logs very hard to read.
The user can still access them with `instance.agent` and `instance.ssl`.

test/unit/connection.test.js

@@ -20,6 +20,7 @@
 'use strict'
 
 const { test } = require('tap')
+const { inspect } = require('util')
 const { createGzip, createDeflate } = require('zlib')
 const { URL } = require('url')
 const intoStream = require('into-stream')
@@ -670,3 +671,45 @@ test('setRole', t => {
 
   t.end()
 })
+
+test('Util.inspect Connection class should hide agent and ssl', t => {
+  t.plan(1)
+
+  const connection = new Connection({
+    url: new URL('http://localhost:9200'),
+    id: 'node-id',
+    headers: { foo: 'bar' }
+  })
+
+  // Removes spaces and new lines because
+  // utils.inspect is handled differently
+  // between major versions of Node.js
+  function cleanStr (str) {
+    return str
+      .replace(/\s/g, '')
+      .replace(/(\r\n|\n|\r)/gm, '')
+  }
+
+  t.strictEqual(cleanStr(inspect(connection)), cleanStr(`{ url:
+   URL {
+     href: 'http://localhost:9200/',
+     origin: 'http://localhost:9200',
+     protocol: 'http:',
+     username: '',
+     password: '',
+     host: 'localhost:9200',
+     hostname: 'localhost',
+     port: '9200',
+     pathname: '/',
+     search: '',
+     searchParams: URLSearchParams {},
+     hash: '' },
+  id: 'node-id',
+  headers: { foo: 'bar' },
+  deadCount: 0,
+  resurrectTimeout: 0,
+  _openRequests: 0,
+  status: 'alive',
+  roles: { master: true, data: true, ingest: true, ml: false } }`)
+  )
+})