Grafana visualization
Grafana is an open source metric visualization suite that can be used to build dashboards from various widgets and data sources. Grafana is traditionally used for visualizing time series data for infrastructure and application monitoring, but it is generic and can be used with pretty much any data source that produces time series and tabular data. Thanks to its monitoring orientation Grafana is suitable for low-latency visualization of frequently changing data. We will use this capability to display the top hashtags and counts, and have them updated as changes occur in the application (with perhaps one to two seconds of end-to-end latency).
In order to use Grafana, we need to tap into the data that is available from the Pub/Sub server. The Pub/Sub server has an HTTP interface, but the data format of the queryable state protocol of the Apex application needs to be adapted to what Grafana requires.
There are two options to accomplish this:
- Implementing a new datasource that...
