mirror of https://github.com/tailscale/tailscale/
util/clientmetrics: add new package to add metrics to the client
And annotate magicsock as a start. And add localapi and debug handlers with the Prometheus-format exporter. Updates #3307 Change-Id: I47c5d535fe54424741df143d052760387248f8d3 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>pull/3311/head
Brad Fitzpatrick
4 years ago
committed by
Brad Fitzpatrick
parent
c5d572f371
commit
57b039c51d
@ -0,0 +1,135 @@
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package clientmetric provides client-side metrics whose values
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// get occasionally logged.
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package clientmetric
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import (
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"fmt"
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"io"
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"sort"
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"sync"
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"sync/atomic"
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)
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var (
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mu sync.Mutex
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metrics = map[string]*Metric{}
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sortedDirty bool
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sorted []*Metric
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)
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// Type is a metric type: counter or gauge.
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type Type uint8
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const (
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TypeGauge Type = iota
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TypeCounter
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)
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// Metric is an integer metric value that's tracked over time.
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//
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// It's safe for concurrent use.
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type Metric struct {
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v int64 // atomic; the metric value
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name string
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lastLogv int64 // v atomic, epoch seconds
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lastLog int64 // atomic, epoch seconds
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logSec int // log every N seconds max
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typ Type
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}
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func (m *Metric) Name() string { return m.name }
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func (m *Metric) Value() int64 { return atomic.LoadInt64(&m.v) }
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func (m *Metric) Type() Type { return m.typ }
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// Add increments m's value by n.
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//
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// If m is of type counter, n should not be negative.
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func (m *Metric) Add(n int64) {
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atomic.AddInt64(&m.v, n)
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}
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// Set sets m's value to v.
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//
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// If m is of type counter, Set should not be used.
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func (m *Metric) Set(v int64) {
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atomic.StoreInt64(&m.v, v)
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}
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// Publish registers a metric in the global map.
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// It panics if the name is a duplicate anywhere in the process.
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func (m *Metric) Publish() {
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mu.Lock()
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defer mu.Unlock()
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if m.name == "" {
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panic("unnamed Metric")
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}
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if _, dup := metrics[m.name]; dup {
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panic("duplicate metric " + m.name)
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}
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metrics[m.name] = m
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sortedDirty = true
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}
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// Metrics returns the sorted list of metrics.
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//
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// The returned slice should not be mutated.
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func Metrics() []*Metric {
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mu.Lock()
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defer mu.Unlock()
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if sortedDirty {
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sortedDirty = false
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sorted = make([]*Metric, 0, len(metrics))
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for _, m := range metrics {
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sorted = append(sorted, m)
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}
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sort.Slice(sorted, func(i, j int) bool {
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return sorted[i].name < sorted[j].name
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})
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}
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return sorted
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}
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// NewUnpublished initializes a new Metric without calling Publish on
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// it.
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func NewUnpublished(name string, typ Type) *Metric {
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return &Metric{
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name: name,
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typ: typ,
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logSec: 10,
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}
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}
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// NewCounter returns a new metric that can only increment.
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func NewCounter(name string) *Metric {
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m := NewUnpublished(name, TypeCounter)
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m.Publish()
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return m
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}
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// NewGauge returns a new metric that can both increment and decrement.
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func NewGauge(name string) *Metric {
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m := NewUnpublished(name, TypeGauge)
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m.Publish()
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return m
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}
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// WritePrometheusExpositionFormat writes all client metrics to w in
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// the Prometheus text-based exposition format.
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//
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// See https://github.com/prometheus/docs/blob/main/content/docs/instrumenting/exposition_formats.md
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func WritePrometheusExpositionFormat(w io.Writer) {
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for _, m := range Metrics() {
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switch m.Type() {
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case TypeGauge:
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fmt.Fprintf(w, "# TYPE %s gauge\n", m.Name())
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case TypeCounter:
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fmt.Fprintf(w, "# TYPE %s counter\n", m.Name())
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}
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fmt.Fprintf(w, "%s %v\n", m.Name(), m.Value())
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}
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}
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