Prometheus Exporter for lotus https://prometheus.io/docs/instrumenting/writing_exporters/
wget https://dl.google.com/go/go1.15.2.linux-amd64.tar.gz sudo tar -xvf go1.15.3.linux-amd64.tar.gz sudo mv go /usr/local
export GO111MODULE=on export GOPROXY=https://goproxy.io
go build .
./lotus-exporter -m f0xxxx [-t height, default latest]