Just use telegraf and the input.http with the next details, of course point to your pi-hole:
[[inputs.http]] #PiHole URL for data in JSON format urls = ["http://192.168.1.3/admin/api.php"] method = "GET" #Overwrite measurement name from default `http` to `pihole_stats` name_override = "pihole_stats" #Exclude host items from tags tagexclude = ["host"] #Data from HTTP in JSON format data_format = "json" #JSON values to set as string fields json_string_fields = ["url", "status"] insecure_skip_verify = true
Restar telegraf, and that's it.
Then download or import this Dashboard to your Grafana, and you should see something similar to the next:
Hope you like it!