Prometheus metrics

Metrics for the processes and other aspects are provided for a Prometheus scraper on /metrics.

You have to set metrics.enable and metrics.enable_prometheus to true in the settings

Currently, available metrics are:

Metric	Type	Dimensions	Description
ffmpeg_process	gauge	core, process, name	General stats per process.
ffmpeg_process_io	gauge	core, process, type, id, index, media, name	Stats per input and output of a process.
mem_limit_bytes	gauge	core	Total available memory in bytes.
mem_free_bytes	gauge	core	Free memory in bytes.
net_rx_bytes	gauge	core, interface	Number of received bytes by interface.
net_tx_bytes	gauge	core, interface	Number of sent bytes by interface.
cpus_system_time_secs	gauge	core, cpu	System time per CPU in seconds.
cpus_user_time_secs	gauge	core, cpu	User time per CPU in seconds.
cpus_idle_time_secs	gauge	core, cpu	Idle time per CPU in seconds.
session_total	counter	core, collector	Total number of sessions by collector.
session_active	gauge	core, collector	Current number of active sessions by collector.
session_rx_bytes	counter	core, collector	Total received bytes by collector.
session_tx_bytes	counter	core, collector	Total sent bytes by collector.