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tailscale/metrics/metrics.go

69 lines
2.0 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
}
// SetInt64 sets the *Int value stored under the given map key.
func (m *LabelMap) SetInt64(key string, v int64) {
m.Get(key).Set(v)
}
// 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)
}
// GetIncrFunc returns a function that increments the expvar.Int named by key.
//
// Most callers should not need this; it exists to satisfy an
// interface elsewhere.
func (m *LabelMap) GetIncrFunc(key string) func(delta int64) {
return m.Get(key).Add
}
// 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()
}