Originally published at: Filtering IoT Sensor Data with Golioth Rest API Queries in Grafana - Golioth
Golioth collects data from your entire IoT sensor fleet and makes it easy to access from the cloud. Data visualization is a common use case and we love using Grafana to make dashboards for our fleets. It can start to get tricky if your devices are sending back mountains of different data. We’ll demonstrate how you can use Golioth REST API Queries to capture specific data endpoints from devices. By doing so, you can focus on the most important data points and utilize them to create powerful visual dashboards in Grafana. Don’t Mix Your Endpoints By far the easiest way to query streaming sensor data is just to ask for all of the events. But this presents an interesting challenge in Grafana. If your query response includes records that don’t have your desired endpoint, Grafana will see that as null and most often this will break your graph: Grafana showing the “Fields have different lengths” error This is because the graph is targetting the sensor endpoint, but if we look at Golioth we can see that the device is sending data to the battery endpoint in between sensor readings. The sensor endpoint doesn’t exist for those readings. Let’s diagnose, and fix this issue using the Query Builder button in the upper right of the LightDB Stream page of the Golioth Console. Using Query Builder to Filter Data As it stands now, the query is asking for all data from all events by using the * wildcard operator: What we really want is just one endpoint that we can graph (along with the time and deviceId). So let’s change the query builder to target the current measurement on channel 0 of…
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