tailscale/metrics/metrics.go
Will Norris 71029cea2d all: update copyright and license headers
This updates all source files to use a new standard header for copyright
and license declaration.  Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.

This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.

Updates #6865

Signed-off-by: Will Norris <will@tailscale.com>
2023-01-27 15:36:29 -08:00

56 lines
1.6 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package metrics contains expvar & Prometheus types and code used by
// Tailscale for monitoring.
package metrics
import "expvar"
// 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.)
type Set struct {
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.
type LabelMap struct {
Label string
expvar.Map
}
// Get returns a direct pointer to the expvar.Int for key, creating it
// if necessary.
func (m *LabelMap) Get(key string) *expvar.Int {
m.Add(key, 0)
return m.Map.Get(key).(*expvar.Int)
}
// GetFloat returns a direct pointer to the expvar.Float for key, creating it
// if necessary.
func (m *LabelMap) GetFloat(key string) *expvar.Float {
m.AddFloat(key, 0.0)
return m.Map.Get(key).(*expvar.Float)
}
// CurrentFDs reports how many file descriptors are currently open.
//
// It only works on Linux. It returns zero otherwise.
func CurrentFDs() int {
return currentFDs()
}