title: Certificate configuration parameter problems connecting to AWS IOT
body: <p>Trying to get my node.js IOT example working but not sure what configuration I need to set to pass to my thingShadow constructor <code>awsIot.thingShadow(config)</code></p>
  
  <p>This is the sample config I get from the AWS dashboard</p>
  
  <pre><code>{
    "host": "foo.iot.us-east-1.amazonaws.com",
      "port": 8883,
      "clientId": "bar",
      "thingName": "bar",
      "caCert": "root-CA.crt",
      "clientCert": "bar-certificate.pem.crt",
      "privateKey": "bar-private.pem.key"
  }
  </code></pre>
  
  <p>However this is the constructor I set based on the sdk readme</p>
  
  <pre><code>{
    keyPath: 'bar-private.pem.key',
    certPath: 'bar-certificate.pem.crt',
    caCert: "root-CA.crt",
    clientId: 'bar'
  }
  </code></pre>
  
  <p>I get the error</p>
  
  <p>events.js:141
        throw er; // Unhandled 'error' event
        ^</p>
  
  <pre><code>Error: unable to get local issuer certificate
      at Error (native)
      at TLSSocket.&lt;anonymous&gt; (_tls_wrap.js:1017:38)
      at emitNone (events.js:67:13)
      at TLSSocket.emit (events.js:166:7)
      at TLSSocket._init.ssl.onclienthello.ssl.oncertcb.TLSSocket._finishInit (_tls_wrap.js:582:8)
      at TLSWrap.ssl.onclienthello.ssl.oncertcb.ssl.onnewsession.ssl.onhandshakedone (_tls_wrap.js:424:38)
  </code></pre>
  
  <p>What is caCert based on - is that a cert that I have in my local path?  If so where do I get it from, the dashboard as a download somewhere?  Am I sending the right certificate files for privateKey?</p>