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prober: support adding key/value labels to probes. (#4250)

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prober: add labels to Probe instances.

This allows especially dynamically-registered probes to have a bunch
more dimensions along which they can be sliced in Prometheus.

Signed-off-by: David Anderson <danderson@tailscale.com>
This commit is contained in:
Dave Anderson
2022-03-22 13:45:11 -07:00
committed by GitHub
parent f3b13604b3
commit 0968b2d55a
2 changed files with 246 additions and 120 deletions
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prober/prober_test.go
+112 -56
View File
@@ -5,6 +5,7 @@
package prober
import (
"bytes"
"context"
"encoding/json"
"errors"
@@ -14,8 +15,10 @@ import (
"testing"
"time"
"github.com/google/go-cmp/cmp"
"tailscale.com/syncs"
"tailscale.com/tstest"
"tailscale.com/tsweb"
)
const (
@@ -24,6 +27,7 @@ const (
quarterProbeInterval = probeInterval / 4
convergenceTimeout = time.Second
convergenceSleep = time.Millisecond
aFewMillis = 20 * time.Millisecond
)
var epoch = time.Unix(0, 0)
@@ -51,7 +55,7 @@ func TestProberTiming(t *testing.T) {
}
}
p.Run("test-probe", probeInterval, func(context.Context) error {
p.Run("test-probe", probeInterval, nil, func(context.Context) error {
invoked <- struct{}{}
return nil
})
@@ -83,7 +87,7 @@ func TestProberRun(t *testing.T) {
var probes []*Probe
for i := 0; i < startingProbes; i++ {
probes = append(probes, p.Run(fmt.Sprintf("probe%d", i), probeInterval, func(context.Context) error {
probes = append(probes, p.Run(fmt.Sprintf("probe%d", i), probeInterval, nil, func(context.Context) error {
mu.Lock()
defer mu.Unlock()
cnt++
@@ -92,6 +96,7 @@ func TestProberRun(t *testing.T) {
}
checkCnt := func(want int) {
t.Helper()
err := tstest.WaitFor(convergenceTimeout, func() error {
mu.Lock()
defer mu.Unlock()
@@ -126,9 +131,8 @@ func TestExpvar(t *testing.T) {
clk := newFakeTime()
p := newForTest(clk.Now, clk.NewTicker)
const aFewMillis = 20 * time.Millisecond
var succeed syncs.AtomicBool
p.Run("probe", probeInterval, func(context.Context) error {
p.Run("probe", probeInterval, map[string]string{"label": "value"}, func(context.Context) error {
clk.Advance(aFewMillis)
if succeed.Get() {
return nil
@@ -138,20 +142,106 @@ func TestExpvar(t *testing.T) {
waitActiveProbes(t, p, 1)
waitExpInt(t, p, "start_secs/probe", 0)
waitExpInt(t, p, "end_secs/probe", 0)
waitExpInt(t, p, "interval_secs/probe", int(probeInterval.Seconds()))
waitExpInt(t, p, "latency_millis/probe", int(aFewMillis.Milliseconds()))
waitExpInt(t, p, "result/probe", 0)
check := func(name string, want probeInfo) {
t.Helper()
err := tstest.WaitFor(convergenceTimeout, func() error {
vars := probeExpvar(t, p)
if got, want := len(vars), 1; got != want {
return fmt.Errorf("wrong probe count in expvar, got %d want %d", got, want)
}
for k, v := range vars {
if k != name {
return fmt.Errorf("wrong probe name in expvar, got %q want %q", k, name)
}
if diff := cmp.Diff(v, &want); diff != "" {
return fmt.Errorf("wrong probe stats (-got+want):\n%s", diff)
}
}
return nil
})
if err != nil {
t.Fatal(err)
}
}
check("probe", probeInfo{
Labels: map[string]string{"label": "value"},
Start: epoch,
End: epoch.Add(aFewMillis),
Latency: aFewMillis.String(),
Result: false,
})
succeed.Set(true)
clk.Advance(probeInterval + halfProbeInterval)
waitExpInt(t, p, "start_secs/probe", int((probeInterval + halfProbeInterval).Seconds()))
waitExpInt(t, p, "end_secs/probe", int((probeInterval + halfProbeInterval).Seconds()))
waitExpInt(t, p, "interval_secs/probe", int(probeInterval.Seconds()))
waitExpInt(t, p, "latency_millis/probe", int(aFewMillis.Milliseconds()))
waitExpInt(t, p, "result/probe", 1)
st := epoch.Add(probeInterval + halfProbeInterval + aFewMillis)
check("probe", probeInfo{
Labels: map[string]string{"label": "value"},
Start: st,
End: st.Add(aFewMillis),
Latency: aFewMillis.String(),
Result: true,
})
}
func TestPrometheus(t *testing.T) {
clk := newFakeTime()
p := newForTest(clk.Now, clk.NewTicker)
var succeed syncs.AtomicBool
p.Run("testprobe", probeInterval, map[string]string{"label": "value"}, func(context.Context) error {
clk.Advance(aFewMillis)
if succeed.Get() {
return nil
}
return errors.New("failing, as instructed by test")
})
waitActiveProbes(t, p, 1)
err := tstest.WaitFor(convergenceTimeout, func() error {
var b bytes.Buffer
p.Expvar().(tsweb.PrometheusVar).WritePrometheus(&b, "probe")
want := strings.TrimSpace(fmt.Sprintf(`
probe_interval_secs{name="testprobe",label="value"} %f
probe_start_secs{name="testprobe",label="value"} %d
probe_end_secs{name="testprobe",label="value"} %d
probe_latency_millis{name="testprobe",label="value"} %d
probe_result{name="testprobe",label="value"} 0
`, probeInterval.Seconds(), epoch.Unix(), epoch.Add(aFewMillis).Unix(), aFewMillis.Milliseconds()))
if diff := cmp.Diff(strings.TrimSpace(b.String()), want); diff != "" {
return fmt.Errorf("wrong probe stats (-got+want):\n%s", diff)
}
return nil
})
if err != nil {
t.Fatal(err)
}
succeed.Set(true)
clk.Advance(probeInterval + halfProbeInterval)
err = tstest.WaitFor(convergenceTimeout, func() error {
var b bytes.Buffer
p.Expvar().(tsweb.PrometheusVar).WritePrometheus(&b, "probe")
start := epoch.Add(probeInterval + halfProbeInterval)
end := start.Add(aFewMillis)
want := strings.TrimSpace(fmt.Sprintf(`
probe_interval_secs{name="testprobe",label="value"} %f
probe_start_secs{name="testprobe",label="value"} %d
probe_end_secs{name="testprobe",label="value"} %d
probe_latency_millis{name="testprobe",label="value"} %d
probe_result{name="testprobe",label="value"} 1
`, probeInterval.Seconds(), start.Unix(), end.Unix(), aFewMillis.Milliseconds()))
if diff := cmp.Diff(strings.TrimSpace(b.String()), want); diff != "" {
return fmt.Errorf("wrong probe stats (-got+want):\n%s", diff)
}
return nil
})
if err != nil {
t.Fatal(err)
}
}
type fakeTicker struct {
@@ -185,7 +275,9 @@ func (t *fakeTicker) fire(now time.Time) {
case t.ch <- now:
default:
}
t.next = now.Add(t.interval)
for now.After(t.next) {
t.next = t.next.Add(t.interval)
}
}
type fakeTime struct {
@@ -200,7 +292,6 @@ func newFakeTime() *fakeTime {
curTime: epoch,
}
ret.Cond = &sync.Cond{L: &ret.Mutex}
ret.Advance(time.Duration(1)) // so that Now never IsZero
return ret
}
@@ -208,8 +299,6 @@ func (t *fakeTime) Now() time.Time {
t.Lock()
defer t.Unlock()
ret := t.curTime
// so that time always seems to advance for the program under test
t.curTime = t.curTime.Add(time.Microsecond)
return ret
}
@@ -237,47 +326,14 @@ func (t *fakeTime) Advance(d time.Duration) {
}
}
func waitExpInt(t *testing.T, p *Prober, path string, want int) {
t.Helper()
err := tstest.WaitFor(convergenceTimeout, func() error {
got, ok := getExpInt(t, p, path)
if !ok {
return fmt.Errorf("expvar %q did not get set", path)
}
if got != want {
return fmt.Errorf("expvar %q is %d, want %d", path, got, want)
}
return nil
})
if err != nil {
t.Fatal(err)
}
}
func getExpInt(t *testing.T, p *Prober, path string) (ret int, ok bool) {
func probeExpvar(t *testing.T, p *Prober) map[string]*probeInfo {
t.Helper()
s := p.Expvar().String()
dec := map[string]interface{}{}
if err := json.Unmarshal([]byte(s), &dec); err != nil {
t.Fatalf("couldn't unmarshal expvar data: %v", err)
ret := map[string]*probeInfo{}
if err := json.Unmarshal([]byte(s), &ret); err != nil {
t.Fatalf("expvar json decode failed: %v", err)
}
var v interface{} = dec
for _, d := range strings.Split(path, "/") {
m, ok := v.(map[string]interface{})
if !ok {
t.Fatalf("expvar path %q ended early with a leaf value", path)
}
child, ok := m[d]
if !ok {
return 0, false
}
v = child
}
f, ok := v.(float64)
if !ok {
return 0, false
}
return int(f), true
return ret
}
func waitActiveProbes(t *testing.T, p *Prober, want int) {