Accumulate network traffic daily

Dear all,
I use metricbeat to collect the running information of the server and then store the data in Elasticsearch. I want to count the network accumulated traffic of each server each day. What should I do?
I wanted to integrate the network velocity, but grafana doesn’t seem to support integration.
I’ve also tried subtracting system.network.in.bytes (the end of the day) from system.network.in.bytes (the end of the day), but I don’t know how to get system.network.in.bytes for a certain moment in grafana.
Do you have any good ideas you can share with me?