Node exporter textfile collector

The textfile collector allows machine-level statistics to be exported out via the Node exporter.

This is useful for monitoring cronjobs, or for writing cronjobs to expose metrics about a machine system that the Node exporter does not support or would not make sense to perform at every scrape (for example, anything involving subprocesses).

from prometheus_client import CollectorRegistry, Gauge, write_to_textfile

registry = CollectorRegistry()
g = Gauge('raid_status', '1 if raid array is okay', registry=registry)
g.set(1)
write_to_textfile('/configured/textfile/path/raid.prom', registry)

A separate registry is used, as the default registry may contain other metrics such as those from the Process Collector.