metrics

Documentation

Overview

Package metrics contains expvar & Prometheus types and code used by Tailscale for monitoring.

Index

• func CurrentFDs() int
• type LabelMap
  • func (m *LabelMap) Get(key string) *expvar.Int
  • func (m *LabelMap) GetFloat(key string) *expvar.Float
• type Set

Functions

func CurrentFDs

func CurrentFDs() int

CurrentFDs reports how many file descriptors are currently open.

It only works on Linux. It returns zero otherwise.

Types

type LabelMap

type LabelMap struct {
	Label string
	expvar.Map
}

LabelMap is a string-to-Var map variable that satisfies the expvar.Var interface.

Semantically, this is mapped by tsweb's Prometheus exporter as a collection of variables with the same name, with a varying label value. Use this to export things that are intuitively breakdowns into different buckets.

func (*LabelMap) Get

func (m *LabelMap) Get(key string) *expvar.Int

Get returns a direct pointer to the expvar.Int for key, creating it if necessary.

func (*LabelMap) GetFloat

func (m *LabelMap) GetFloat(key string) *expvar.Float

GetFloat returns a direct pointer to the expvar.Float for key, creating it if necessary.

type Set

type Set struct {
	expvar.Map
}

Set is a string-to-Var map variable that satisfies the expvar.Var interface.

Semantically, this is mapped by tsweb's Prometheus exporter as a collection of unrelated variables exported with a common prefix.

This lets us have tsweb recognize *expvar.Map for different purposes in the future. (Or perhaps all uses of expvar.Map will require explicit types like this one, declaring how we want tsweb to export it to Prometheus.)