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usermetric: add initial user-facing metrics 

This commit adds a new usermetric package and wires
up metrics across the tailscale client.

Updates tailscale/corp#22075

Co-authored-by: Anton Tolchanov <anton@tailscale.com>
Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
This commit is contained in:
Kristoffer Dalby 2024-08-01 13:00:36 +02:00 committed by Kristoffer Dalby
parent 06c31f4e91
commit a2c42d3cd4
17 changed files with 368 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
client/tailscale/localclient.go
View File

@ -353,6 +353,12 @@ func (lc *LocalClient) DaemonMetrics(ctx context.Context) ([]byte, error) {
return lc.get200(ctx, "/localapi/v0/metrics")
}
// UserMetrics returns the user metrics in
// the Prometheus text exposition format.
func (lc *LocalClient) UserMetrics(ctx context.Context) ([]byte, error) {
return lc.get200(ctx, "/localapi/v0/usermetrics")
}
// IncrementCounter increments the value of a Tailscale daemon's counter
// metric by the given delta. If the metric has yet to exist, a new counter
// metric is created and initialized to delta.

6
client/web/web.go
View File

@ -283,6 +283,12 @@ func (s *Server) serve(w http.ResponseWriter, r *http.Request) {
}
}
if r.URL.Path == "/metrics" {
r.URL.Path = "/api/local/v0/usermetrics"
s.proxyRequestToLocalAPI(w, r)
return
}
if strings.HasPrefix(r.URL.Path, "/api/") {
switch {
case r.URL.Path == "/api/auth" && r.Method == httpm.GET:

1
cmd/derper/depaware.txt
View File

@ -163,6 +163,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
tailscale.com/util/syspolicy from tailscale.com/ipn
tailscale.com/util/syspolicy/internal from tailscale.com/util/syspolicy/setting
tailscale.com/util/syspolicy/setting from tailscale.com/util/syspolicy
tailscale.com/util/usermetric from tailscale.com/health
tailscale.com/util/vizerror from tailscale.com/tailcfg+
W 💣 tailscale.com/util/winutil from tailscale.com/hostinfo+
W 💣 tailscale.com/util/winutil/winenv from tailscale.com/hostinfo+

2
cmd/k8s-operator/depaware.txt
View File

@ -754,6 +754,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
tailscale.com/tstime from tailscale.com/cmd/k8s-operator+
tailscale.com/tstime/mono from tailscale.com/net/tstun+
tailscale.com/tstime/rate from tailscale.com/derp+
tailscale.com/tsweb/varz from tailscale.com/util/usermetric
tailscale.com/types/appctype from tailscale.com/ipn/ipnlocal
tailscale.com/types/dnstype from tailscale.com/ipn/ipnlocal+
tailscale.com/types/empty from tailscale.com/ipn+
@ -812,6 +813,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
tailscale.com/util/testenv from tailscale.com/control/controlclient+
tailscale.com/util/truncate from tailscale.com/logtail
tailscale.com/util/uniq from tailscale.com/ipn/ipnlocal+
tailscale.com/util/usermetric from tailscale.com/health+
tailscale.com/util/vizerror from tailscale.com/tailcfg+
💣 tailscale.com/util/winutil from tailscale.com/clientupdate+
W 💣 tailscale.com/util/winutil/authenticode from tailscale.com/clientupdate+

4
cmd/tailscale/depaware.txt
View File

@ -99,7 +99,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
tailscale.com/ipn from tailscale.com/client/tailscale+
tailscale.com/ipn/ipnstate from tailscale.com/client/tailscale+
tailscale.com/licenses from tailscale.com/client/web+
tailscale.com/metrics from tailscale.com/derp
tailscale.com/metrics from tailscale.com/derp+
tailscale.com/net/captivedetection from tailscale.com/net/netcheck
tailscale.com/net/dns/recursive from tailscale.com/net/dnsfallback
tailscale.com/net/dnscache from tailscale.com/control/controlhttp+
@ -132,6 +132,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
tailscale.com/tstime from tailscale.com/control/controlhttp+
tailscale.com/tstime/mono from tailscale.com/tstime/rate
tailscale.com/tstime/rate from tailscale.com/cmd/tailscale/cli+
tailscale.com/tsweb/varz from tailscale.com/util/usermetric
tailscale.com/types/dnstype from tailscale.com/tailcfg
tailscale.com/types/empty from tailscale.com/ipn
tailscale.com/types/ipproto from tailscale.com/net/flowtrack+
@ -173,6 +174,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
tailscale.com/util/syspolicy/setting from tailscale.com/util/syspolicy
tailscale.com/util/testenv from tailscale.com/cmd/tailscale/cli
tailscale.com/util/truncate from tailscale.com/cmd/tailscale/cli
tailscale.com/util/usermetric from tailscale.com/health
tailscale.com/util/vizerror from tailscale.com/tailcfg+
💣 tailscale.com/util/winutil from tailscale.com/clientupdate+
W 💣 tailscale.com/util/winutil/authenticode from tailscale.com/clientupdate

3
cmd/tailscaled/depaware.txt
View File

@ -343,7 +343,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
tailscale.com/tstime from tailscale.com/control/controlclient+
tailscale.com/tstime/mono from tailscale.com/net/tstun+
tailscale.com/tstime/rate from tailscale.com/derp+
tailscale.com/tsweb/varz from tailscale.com/cmd/tailscaled
tailscale.com/tsweb/varz from tailscale.com/cmd/tailscaled+
tailscale.com/types/appctype from tailscale.com/ipn/ipnlocal
tailscale.com/types/dnstype from tailscale.com/ipn/ipnlocal+
tailscale.com/types/empty from tailscale.com/ipn+
@ -403,6 +403,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
tailscale.com/util/testenv from tailscale.com/ipn/ipnlocal+
tailscale.com/util/truncate from tailscale.com/logtail
tailscale.com/util/uniq from tailscale.com/ipn/ipnlocal+
tailscale.com/util/usermetric from tailscale.com/health+
tailscale.com/util/vizerror from tailscale.com/tailcfg+
💣 tailscale.com/util/winutil from tailscale.com/clientupdate+
W 💣 tailscale.com/util/winutil/authenticode from tailscale.com/clientupdate+

25
health/health.go
View File

@ -8,6 +8,7 @@ package health
import (
"context"
"errors"
"expvar"
"fmt"
"maps"
"net/http"
@ -25,6 +26,7 @@ import (
"tailscale.com/util/mak"
"tailscale.com/util/multierr"
"tailscale.com/util/set"
"tailscale.com/util/usermetric"
"tailscale.com/version"
)
@ -1202,6 +1204,18 @@ func (t *Tracker) ReceiveFuncStats(which ReceiveFunc) *ReceiveFuncStats {
}
func (t *Tracker) doOnceInit() {
metricHealthMessage.Set(metricHealthMessageLabel{
Type: "warning",
}, expvar.Func(func() any {
if t.nil() {
return 0
}
t.mu.Lock()
defer t.mu.Unlock()
t.updateBuiltinWarnablesLocked()
return int64(len(t.stringsLocked()))
}))
for i := range t.MagicSockReceiveFuncs {
f := &t.MagicSockReceiveFuncs[i]
f.name = (ReceiveFunc(i)).String()
@ -1232,3 +1246,14 @@ func (t *Tracker) checkReceiveFuncsLocked() {
f.missing = true
}
}
type metricHealthMessageLabel struct {
// TODO: break down by warnable.severity as well?
Type string
}
var metricHealthMessage = usermetric.NewMultiLabelMap[metricHealthMessageLabel](
"tailscaled_health_messages",
"gauge",
"Number of health messages broken down by type.",
)

13
ipn/ipnlocal/local.go
View File

@ -106,6 +106,7 @@ import (
"tailscale.com/util/systemd"
"tailscale.com/util/testenv"
"tailscale.com/util/uniq"
"tailscale.com/util/usermetric"
"tailscale.com/version"
"tailscale.com/version/distro"
"tailscale.com/wgengine"
@ -117,6 +118,9 @@ import (
"tailscale.com/wgengine/wgcfg/nmcfg"
)
var metricAdvertisedRoutes = usermetric.NewGauge(
"tailscaled_advertised_routes", "Number of advertised network routes (e.g. by a subnet router)")
var controlDebugFlags = getControlDebugFlags()
func getControlDebugFlags() []string {
@ -4646,6 +4650,15 @@ func (b *LocalBackend) applyPrefsToHostinfoLocked(hi *tailcfg.Hostinfo, prefs ip
hi.ShieldsUp = prefs.ShieldsUp()
hi.AllowsUpdate = envknob.AllowsRemoteUpdate() || prefs.AutoUpdate().Apply.EqualBool(true)
// count routes without exit node routes
var routes int64
for _, route := range hi.RoutableIPs {
if route.Bits() != 0 {
routes++
}
}
metricAdvertisedRoutes.Set(float64(routes))
var sshHostKeys []string
if prefs.RunSSH() && envknob.CanSSHD() {
// TODO(bradfitz): this is called with b.mu held. Not ideal.

15
ipn/localapi/localapi.go
View File

@ -63,6 +63,8 @@ import (
"tailscale.com/util/osuser"
"tailscale.com/util/progresstracking"
"tailscale.com/util/rands"
"tailscale.com/util/testenv"
"tailscale.com/util/usermetric"
"tailscale.com/version"
"tailscale.com/wgengine/magicsock"
)
@ -141,6 +143,7 @@ var handler = map[string]localAPIHandler{
"update/install": (*Handler).serveUpdateInstall,
"update/progress": (*Handler).serveUpdateProgress,
"upload-client-metrics": (*Handler).serveUploadClientMetrics,
"usermetrics": (*Handler).serveUserMetrics,
"watch-ipn-bus": (*Handler).serveWatchIPNBus,
"whois": (*Handler).serveWhoIs,
}
@ -571,6 +574,18 @@ func (h *Handler) serveMetrics(w http.ResponseWriter, r *http.Request) {
clientmetric.WritePrometheusExpositionFormat(w)
}
// TODO(kradalby): Remove this once we have landed on a final set of
// metrics to export to clients and consider the metrics stable.
var debugUsermetricsEndpoint = envknob.RegisterBool("TS_DEBUG_USER_METRICS")
func (h *Handler) serveUserMetrics(w http.ResponseWriter, r *http.Request) {
if !testenv.InTest() && !debugUsermetricsEndpoint() {
http.Error(w, "usermetrics debug flag not enabled", http.StatusForbidden)
return
}
usermetric.Handler(w, r)
}
func (h *Handler) serveDebug(w http.ResponseWriter, r *http.Request) {
if !h.PermitWrite {
http.Error(w, "debug access denied", http.StatusForbidden)

32
metrics/multilabelmap.go
View File

@ -39,7 +39,7 @@ func NewMultiLabelMap[T comparable](name string, promType, helpText string) *Mul
Help: helpText,
}
var zero T
_ = labelString(zero) // panic early if T is invalid
_ = LabelString(zero) // panic early if T is invalid
expvar.Publish(name, m)
return m
}
@ -50,8 +50,10 @@ type labelsAndValue[T comparable] struct {
val expvar.Var
}
// labelString returns a Prometheus-formatted label string for the given key.
func labelString(k any) string {
// LabelString returns a Prometheus-formatted label string for the given key.
// k must be a struct type with scalar fields, as required by MultiLabelMap,
// if k is not a struct, it will panic.
func LabelString(k any) string {
rv := reflect.ValueOf(k)
t := rv.Type()
if t.Kind() != reflect.Struct {
@ -150,7 +152,7 @@ func (v *MultiLabelMap[T]) Init() *MultiLabelMap[T] {
//
// v.mu must be held.
func (v *MultiLabelMap[T]) addKeyLocked(key T, val expvar.Var) {
ls := labelString(key)
ls := LabelString(key)
ent := labelsAndValue[T]{key, ls, val}
// Using insertion sort to place key into the already-sorted v.keys.
@ -209,6 +211,26 @@ func (v *MultiLabelMap[T]) Set(key T, val expvar.Var) {
v.m.Store(key, val)
}
// SetInt sets val to the *[expvar.Int] value stored under the given map key,
// creating it if it doesn't exist yet.
// It does nothing if key exists but is of the wrong type.
func (v *MultiLabelMap[T]) SetInt(key T, val int64) {
// Set to Int; ignore otherwise.
if iv, ok := v.getOrFill(key, newInt).(*expvar.Int); ok {
iv.Set(val)
}
}
// SetFloat sets val to the *[expvar.Float] value stored under the given map key,
// creating it if it doesn't exist yet.
// It does nothing if key exists but is of the wrong type.
func (v *MultiLabelMap[T]) SetFloat(key T, val float64) {
// Set to Float; ignore otherwise.
if iv, ok := v.getOrFill(key, newFloat).(*expvar.Float); ok {
iv.Set(val)
}
}
// Add adds delta to the *[expvar.Int] value stored under the given map key,
// creating it if it doesn't exist yet.
// It does nothing if key exists but is of the wrong type.
@ -234,7 +256,7 @@ func (v *MultiLabelMap[T]) AddFloat(key T, delta float64) {
// This is not optimized for highly concurrent usage; it's presumed to only be
// used rarely, at startup.
func (v *MultiLabelMap[T]) Delete(key T) {
ls := labelString(key)
ls := LabelString(key)
v.mu.Lock()
defer v.mu.Unlock()

14
metrics/multilabelmap_test.go
View File

@ -5,6 +5,7 @@ package metrics
import (
"bytes"
"expvar"
"fmt"
"io"
"testing"
@ -22,6 +23,12 @@ func TestMultilabelMap(t *testing.T) {
m.Add(L2{"b", "b"}, 3)
m.Add(L2{"a", "a"}, 1)
m.SetFloat(L2{"sf", "sf"}, 3.5)
m.SetFloat(L2{"sf", "sf"}, 5.5)
m.Set(L2{"sfunc", "sfunc"}, expvar.Func(func() any { return 3 }))
m.SetInt(L2{"si", "si"}, 3)
m.SetInt(L2{"si", "si"}, 5)
cur := func() string {
var buf bytes.Buffer
m.Do(func(kv KeyValue[L2]) {
@ -33,7 +40,7 @@ func TestMultilabelMap(t *testing.T) {
return buf.String()
}
if g, w := cur(), "a/a=1,a/b=2,b/b=3,b/c=4"; g != w {
if g, w := cur(), "a/a=1,a/b=2,b/b=3,b/c=4,sf/sf=5.5,sfunc/sfunc=3,si/si=5"; g != w {
t.Errorf("got %q; want %q", g, w)
}
@ -43,6 +50,9 @@ func TestMultilabelMap(t *testing.T) {
metricname{foo="a",bar="b"} 2
metricname{foo="b",bar="b"} 3
metricname{foo="b",bar="c"} 4
metricname{foo="sf",bar="sf"} 5.5
metricname{foo="sfunc",bar="sfunc"} 3
metricname{foo="si",bar="si"} 5
`
if got := buf.String(); got != want {
t.Errorf("promtheus output = %q; want %q", got, want)
@ -50,7 +60,7 @@ metricname{foo="b",bar="c"} 4
m.Delete(L2{"b", "b"})
if g, w := cur(), "a/a=1,a/b=2,b/c=4"; g != w {
if g, w := cur(), "a/a=1,a/b=2,b/c=4,sf/sf=5.5,sfunc/sfunc=3,si/si=5"; g != w {
t.Errorf("got %q; want %q", g, w)
}

40
net/tstun/wrap.go
View File

@ -34,6 +34,7 @@ import (
"tailscale.com/types/key"
"tailscale.com/types/logger"
"tailscale.com/util/clientmetric"
"tailscale.com/util/usermetric"
"tailscale.com/wgengine/capture"
"tailscale.com/wgengine/filter"
"tailscale.com/wgengine/netstack/gro"
@ -868,6 +869,9 @@ func (t *Wrapper) filterPacketOutboundToWireGuard(p *packet.Parsed, pc *peerConf
if filt.RunOut(p, t.filterFlags) != filter.Accept {
metricPacketOutDropFilter.Add(1)
metricOutboundDroppedPacketsTotal.Add(dropPacketLabel{
Reason: DropReasonACL,
}, 1)
return filter.Drop
}
@ -876,7 +880,6 @@ func (t *Wrapper) filterPacketOutboundToWireGuard(p *packet.Parsed, pc *peerConf
return res
}
}
return filter.Accept
}
@ -1133,6 +1136,9 @@ func (t *Wrapper) filterPacketInboundFromWireGuard(p *packet.Parsed, captHook ca
if outcome != filter.Accept {
metricPacketInDropFilter.Add(1)
metricInboundDroppedPacketsTotal.Add(dropPacketLabel{
Reason: DropReasonACL,
}, 1)
// Tell them, via TSMP, we're dropping them due to the ACL.
// Their host networking stack can translate this into ICMP
@ -1210,6 +1216,11 @@ func (t *Wrapper) Write(buffs [][]byte, offset int) (int, error) {
if len(buffs) > 0 {
t.noteActivity()
_, err := t.tdevWrite(buffs, offset)
if err != nil {
metricInboundDroppedPacketsTotal.Add(dropPacketLabel{
Reason: DropReasonError,
}, int64(len(buffs)))
}
return len(buffs), err
}
return 0, nil
@ -1449,6 +1460,33 @@ var (
metricPacketOutDropSelfDisco = clientmetric.NewCounter("tstun_out_to_wg_drop_self_disco")
)
type DropReason string
const (
DropReasonACL DropReason = "acl"
DropReasonError DropReason = "error"
)
type dropPacketLabel struct {
// Reason indicates what we have done with the packet, and has the following values:
// - acl (rejected packets because of ACL)
// - error (rejected packets because of an error)
Reason DropReason
}
var (
metricInboundDroppedPacketsTotal = usermetric.NewMultiLabelMap[dropPacketLabel](
"tailscaled_inbound_dropped_packets_total",
"counter",
"Counts the number of dropped packets received by the node from other peers",
)
metricOutboundDroppedPacketsTotal = usermetric.NewMultiLabelMap[dropPacketLabel](
"tailscaled_outbound_dropped_packets_total",
"counter",
"Counts the number of packets dropped while being sent to other peers",
)
)
func (t *Wrapper) InstallCaptureHook(cb capture.Callback) {
t.captureHook.Store(cb)
}

22
net/tstun/wrap_test.go
View File

@ -315,6 +315,12 @@ func mustHexDecode(s string) []byte {
}
func TestFilter(t *testing.T) {
// Reset the metrics before test. These are global
// so the different tests might have affected them.
metricInboundDroppedPacketsTotal.SetInt(dropPacketLabel{Reason: DropReasonACL}, 0)
metricInboundDroppedPacketsTotal.SetInt(dropPacketLabel{Reason: DropReasonError}, 0)
metricOutboundDroppedPacketsTotal.SetInt(dropPacketLabel{Reason: DropReasonACL}, 0)
chtun, tun := newChannelTUN(t.Logf, true)
defer tun.Close()
@ -429,6 +435,22 @@ func TestFilter(t *testing.T) {
}
})
}
inACL := metricInboundDroppedPacketsTotal.Get(dropPacketLabel{Reason: DropReasonACL})
inError := metricInboundDroppedPacketsTotal.Get(dropPacketLabel{Reason: DropReasonError})
outACL := metricOutboundDroppedPacketsTotal.Get(dropPacketLabel{Reason: DropReasonACL})
assertMetricPackets(t, "inACL", "3", inACL.String())
assertMetricPackets(t, "inError", "0", inError.String())
assertMetricPackets(t, "outACL", "1", outACL.String())
}
func assertMetricPackets(t *testing.T, metricName, want, got string) {
t.Helper()
if want != got {
t.Errorf("%s got unexpected value, got %s, want %s", metricName, got, want)
}
}
func TestAllocs(t *testing.T) {

65
tsnet/tsnet_test.go
View File

@ -31,8 +31,10 @@ import (
"testing"
"time"
"github.com/google/go-cmp/cmp"
"golang.org/x/net/proxy"
"tailscale.com/cmd/testwrapper/flakytest"
"tailscale.com/health"
"tailscale.com/ipn"
"tailscale.com/ipn/store/mem"
"tailscale.com/net/netns"
@ -815,3 +817,66 @@ func TestUDPConn(t *testing.T) {
t.Errorf("got %q, want world", got)
}
}
func TestUserMetrics(t *testing.T) {
tstest.ResourceCheck(t)
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
// testWarnable is a Warnable that is used within this package for testing purposes only.
var testWarnable = health.Register(&health.Warnable{
Code: "test-warnable-tsnet",
Title: "Test warnable",
Severity: health.SeverityLow,
Text: func(args health.Args) string {
return args[health.ArgError]
},
})
controlURL, c := startControl(t)
s1, _, s1PubKey := startServer(t, ctx, controlURL, "s1")
s1.lb.EditPrefs(&ipn.MaskedPrefs{
Prefs: ipn.Prefs{
AdvertiseRoutes: []netip.Prefix{
netip.MustParsePrefix("192.0.2.0/24"),
netip.MustParsePrefix("192.0.3.0/24"),
},
},
AdvertiseRoutesSet: true,
})
c.SetSubnetRoutes(s1PubKey, []netip.Prefix{netip.MustParsePrefix("192.0.2.0/24")})
lc1, err := s1.LocalClient()
if err != nil {
t.Fatal(err)
}
ht := s1.lb.HealthTracker()
ht.SetUnhealthy(testWarnable, health.Args{"Text": "Hello world 1"})
metrics1, err := lc1.UserMetrics(ctx)
if err != nil {
t.Fatal(err)
}
// Note that this test will check for two warnings because the health
// tracker will have two warnings: one from the testWarnable, added in
// this test, and one because we are running the dev/unstable version
// of tailscale.
want := `# TYPE tailscaled_advertised_routes gauge
# HELP tailscaled_advertised_routes Number of advertised network routes (e.g. by a subnet router)
tailscaled_advertised_routes 2
# TYPE tailscaled_health_messages gauge
# HELP tailscaled_health_messages Number of health messages broken down by type.
tailscaled_health_messages{type="warning"} 2
# TYPE tailscaled_inbound_dropped_packets_total counter
# HELP tailscaled_inbound_dropped_packets_total Counts the number of dropped packets received by the node from other peers
# TYPE tailscaled_outbound_dropped_packets_total counter
# HELP tailscaled_outbound_dropped_packets_total Counts the number of packets dropped while being sent to other peers
`
if diff := cmp.Diff(want, string(metrics1)); diff != "" {
t.Fatalf("unexpected metrics (-want +got):\n%s", diff)
}
}

33
tsweb/varz/varz.go
View File

@ -273,19 +273,28 @@ type sortedKVs struct {
//
// This will evolve over time, or perhaps be replaced.
func Handler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/plain;version=0.0.4;charset=utf-8")
ExpvarDoHandler(expvarDo)(w, r)
}
s := sortedKVsPool.Get().(*sortedKVs)
defer sortedKVsPool.Put(s)
s.kvs = s.kvs[:0]
expvarDo(func(kv expvar.KeyValue) {
s.kvs = append(s.kvs, sortedKV{kv, removeTypePrefixes(kv.Key)})
})
sort.Slice(s.kvs, func(i, j int) bool {
return s.kvs[i].sortKey < s.kvs[j].sortKey
})
for _, e := range s.kvs {
writePromExpVar(w, "", e.KeyValue)
// ExpvarDoHandler handler returns a Handler like above, but takes an optional
// expvar.Do func allow the usage of alternative containers of metrics, other
// than the global expvar.Map.
func ExpvarDoHandler(expvarDoFunc func(f func(expvar.KeyValue))) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/plain;version=0.0.4;charset=utf-8")
s := sortedKVsPool.Get().(*sortedKVs)
defer sortedKVsPool.Put(s)
s.kvs = s.kvs[:0]
expvarDoFunc(func(kv expvar.KeyValue) {
s.kvs = append(s.kvs, sortedKV{kv, removeTypePrefixes(kv.Key)})
})
sort.Slice(s.kvs, func(i, j int) bool {
return s.kvs[i].sortKey < s.kvs[j].sortKey
})
for _, e := range s.kvs {
writePromExpVar(w, "", e.KeyValue)
}
}
}

84
util/usermetric/usermetric.go Normal file
View File

@ -0,0 +1,84 @@
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package usermetric provides a container and handler
// for user-facing metrics.
package usermetric
import (
"expvar"
"fmt"
"io"
"net/http"
"tailscale.com/metrics"
"tailscale.com/tsweb/varz"
)
var vars expvar.Map
// NewMultiLabelMap creates and register a new
// MultiLabelMap[T] variable with the given name and returns it.
// The variable is registered with the userfacing metrics package.
//
// Note that usermetric are not protected against duplicate
// metrics name. It is the caller's responsibility to ensure that
// the name is unique.
func NewMultiLabelMap[T comparable](name string, promType, helpText string) *metrics.MultiLabelMap[T] {
m := &metrics.MultiLabelMap[T]{
Type: promType,
Help: helpText,
}
var zero T
_ = metrics.LabelString(zero) // panic early if T is invalid
vars.Set(name, m)
return m
}
// Gauge is a gauge metric with no labels.
type Gauge struct {
m *expvar.Float
help string
}
// NewGauge creates and register a new gauge metric with the given name and help text.
func NewGauge(name, help string) *Gauge {
g := &Gauge{&expvar.Float{}, help}
vars.Set(name, g)
return g
}
// Set sets the gauge to the given value.
func (g *Gauge) Set(v float64) {
g.m.Set(v)
}
// String returns the string of the underlying expvar.Float.
// This satisfies the expvar.Var interface.
func (g *Gauge) String() string {
return g.m.String()
}
// WritePrometheus writes the gauge metric in Prometheus format to the given writer.
// This satisfies the varz.PrometheusWriter interface.
func (g *Gauge) WritePrometheus(w io.Writer, name string) {
io.WriteString(w, "# TYPE ")
io.WriteString(w, name)
io.WriteString(w, " gauge\n")
if g.help != "" {
io.WriteString(w, "# HELP ")
io.WriteString(w, name)
io.WriteString(w, " ")
io.WriteString(w, g.help)
io.WriteString(w, "\n")
}
io.WriteString(w, name)
fmt.Fprintf(w, " %v\n", g.m.Value())
}
// Handler returns a varz.Handler that serves the userfacing expvar contained
// in this package.
func Handler(w http.ResponseWriter, r *http.Request) {
varz.ExpvarDoHandler(vars.Do)(w, r)
}

25
util/usermetric/usermetric_test.go Normal file
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@ -0,0 +1,25 @@
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package usermetric
import (
"bytes"
"testing"
)
func TestGauge(t *testing.T) {
g := NewGauge("test_gauge", "This is a test gauge")
g.Set(15)
var buf bytes.Buffer
g.WritePrometheus(&buf, "test_gauge")
const want = `# TYPE test_gauge gauge
# HELP test_gauge This is a test gauge
test_gauge 15
`
if got := buf.String(); got != want {
t.Errorf("got %q; want %q", got, want)
}
}