Vega Webinar - scatter plot showing web requests for various file types

webinar-demo1.hjson

{
  $schema: https://vega.github.io/schema/vega-lite/v2.json
  data: {

    // Get 10000 documents from ES
    url: {
      %context%: true
      %timefield%: @timestamp
      index: logstash-*
      body: {
        size: 10000
        _source: ["@timestamp", "extension"]
      }
    }
    format: {property: "hits.hits"}
  }
  
  // Parse timestamp and copy extension into new variables
  transform: [
    {calculate: "toDate(datum._source['@timestamp'])", as: "time"}
    {calculate: "datum._source.extension", as: "ext"}
  ]

  // Draw results as colored circles
  mark: circle
  encoding: {
    x: {
      field: time
      type: temporal
      axis: {title: null, labelAngle: 30}
    }
    y: {
      field: ext
      type: nominal
      axis: {title: null}
    }
    color: {field: "ext", type: "nominal"}
  }
}