Add a concurrent end-to-end test for observe-register-gather

This is an attempt to expose
https://github.com/istio/istio/issues/8906 .  The failure to do so
makes me believe the error is either already fixed in current
client_golang, or something weird I haven't spotted yet is happening
in the istio code.

Signed-off-by: beorn7 <beorn@soundcloud.com>
This commit is contained in:
beorn7 2018-10-10 16:59:24 +02:00
parent e1fb14a776
commit 5e8ac3cd58
1 changed files with 99 additions and 0 deletions

View File

@ -21,9 +21,12 @@ package prometheus_test
import (
"bytes"
"math/rand"
"net/http"
"net/http/httptest"
"sync"
"testing"
"time"
dto "github.com/prometheus/client_model/go"
@ -772,3 +775,99 @@ func TestAlreadyRegistered(t *testing.T) {
t.Error("unexpected error:", err)
}
}
// TestHistogramVecRegisterGatherConcurrency is an end-to-end test that
// concurrently calls Observe on random elements of a HistogramVec while the
// same HistogramVec is registered concurrently and the Gather method of the
// registry is called concurrently.
func TestHistogramVecRegisterGatherConcurrency(t *testing.T) {
var (
reg = prometheus.NewPedanticRegistry()
hv = prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "test_histogram",
Help: "This helps testing.",
ConstLabels: prometheus.Labels{"foo": "bar"},
},
[]string{"one", "two", "three"},
)
labelValues = []string{"a", "b", "c", "alpha", "beta", "gamma", "aleph", "beth", "gimel"}
quit = make(chan struct{})
wg sync.WaitGroup
)
observe := func() {
defer wg.Done()
for {
select {
case <-quit:
return
default:
obs := rand.NormFloat64()*.1 + .2
hv.WithLabelValues(
labelValues[rand.Intn(len(labelValues))],
labelValues[rand.Intn(len(labelValues))],
labelValues[rand.Intn(len(labelValues))],
).Observe(obs)
}
}
}
register := func() {
defer wg.Done()
for {
select {
case <-quit:
return
default:
if err := reg.Register(hv); err != nil {
if _, ok := err.(prometheus.AlreadyRegisteredError); !ok {
t.Error("Registering failed:", err)
}
}
time.Sleep(7 * time.Millisecond)
}
}
}
gather := func() {
defer wg.Done()
for {
select {
case <-quit:
return
default:
if g, err := reg.Gather(); err != nil {
t.Error("Gathering failed:", err)
} else {
if len(g) == 0 {
continue
}
if len(g) != 1 {
t.Error("Gathered unexpected number of metric families:", len(g))
}
if len(g[0].Metric[0].Label) != 4 {
t.Error("Gathered unexpected number of label pairs:", len(g[0].Metric[0].Label))
}
}
time.Sleep(4 * time.Millisecond)
}
}
}
wg.Add(10)
go observe()
go observe()
go register()
go observe()
go gather()
go observe()
go register()
go observe()
go gather()
go observe()
time.Sleep(time.Second)
close(quit)
wg.Wait()
}