collector: Add goleak goroutine leak checker to tests

collector/collector_test.go

@@ -0,0 +1,24 @@
+// Copyright The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package collector
+
+import (
+	"testing"
+
+	"go.uber.org/goleak"
+)
+
+func TestMain(m *testing.M) {
+	goleak.VerifyTestMain(m)
+}

collector/diskstats_linux_test.go

@@ -20,6 +20,7 @@ import (
 	"io"
 	"log/slog"
 	"strings"
+	"sync"
 	"testing"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -329,7 +330,10 @@ node_disk_written_bytes_total{device="vda"} 1.0938236928e+11
 	reg.MustRegister(c)
 
 	sink := make(chan prometheus.Metric)
+	var wg sync.WaitGroup
+	wg.Add(1)
 	go func() {
+		defer wg.Done()
 		err = collector.Update(sink)
 		if err != nil {
 			panic(fmt.Errorf("failed to update collector: %s", err))
@@ -341,4 +345,5 @@ node_disk_written_bytes_total{device="vda"} 1.0938236928e+11
 	if err != nil {
 		t.Fatal(err)
 	}
+	wg.Wait()
 }

collector/ethtool_linux_test.go

@@ -24,6 +24,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"syscall"
 	"testing"
 
@@ -389,7 +390,10 @@ node_network_supported_speed_bytes{device="eth0",duplex="half",mode="10baseT"} 1
 	reg.MustRegister(c)
 
 	sink := make(chan prometheus.Metric)
+	var wg sync.WaitGroup
+	wg.Add(1)
 	go func() {
+		defer wg.Done()
 		err = collector.Update(sink)
 		if err != nil {
 			panic(fmt.Errorf("failed to update collector: %s", err))
@@ -401,4 +405,5 @@ node_network_supported_speed_bytes{device="eth0",duplex="half",mode="10baseT"} 1
 	if err != nil {
 		t.Fatal(err)
 	}
+	wg.Wait()
 }

collector/ipvs_linux_test.go

@@ -24,6 +24,7 @@ import (
 	"net/http/httptest"
 	"os"
 	"strings"
+	"sync"
 	"testing"
 
 	"github.com/alecthomas/kingpin/v2"
@@ -128,18 +129,28 @@ func TestIPVSCollector(t *testing.T) {
 			}
 
 			sink := make(chan prometheus.Metric)
+			var wg sync.WaitGroup
+			wg.Add(1)
 			go func() {
+				defer wg.Done()
 				err = collector.Update(sink)
 				if err != nil {
 					panic(fmt.Sprintf("failed to update collector: %v", err))
 				}
+				close(sink)
 			}()
 			for _, expected := range test.expects {
 				got := (<-sink).Desc().String()
 				if expected != got {
 					t.Fatalf("Expected '%s' but got '%s'", expected, got)
 				}
 			}
+			// Drain remaining metrics so the goroutine can finish.
+			go func() {
+				for range sink {
+				}
+			}()
+			wg.Wait()
 		})
 	}
 }

collector/mdadm_linux_test.go

@@ -19,6 +19,7 @@ import (
 	"log/slog"
 	"os"
 	"strings"
+	"sync"
 	"testing"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -278,7 +279,10 @@ func TestMdadmStats(t *testing.T) {
 	reg.MustRegister(c)
 
 	sink := make(chan prometheus.Metric)
+	var wg sync.WaitGroup
+	wg.Add(1)
 	go func() {
+		defer wg.Done()
 		err := collector.Update(sink)
 		if err != nil {
 			panic(err)
@@ -290,4 +294,5 @@ func TestMdadmStats(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	wg.Wait()
 }

collector/watchdog_test.go

@@ -20,6 +20,7 @@ import (
 	"io"
 	"log/slog"
 	"strings"
+	"sync"
 	"testing"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -76,7 +77,10 @@ func TestWatchdogStats(t *testing.T) {
 	reg.MustRegister(&testWatchdogCollector{wc: c})
 
 	sink := make(chan prometheus.Metric)
+	var wg sync.WaitGroup
+	wg.Add(1)
 	go func() {
+		defer wg.Done()
 		err = c.Update(sink)
 		if err != nil {
 			panic(fmt.Errorf("failed to update collector: %s", err))
@@ -88,4 +92,5 @@ func TestWatchdogStats(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	wg.Wait()
 }

collector/xfrm_test.go

@@ -16,7 +16,6 @@
 package collector
 
 import (
-	"fmt"
 	"io"
 	"log/slog"
 	"strings"
@@ -134,15 +133,6 @@ func TestXfrmStats(t *testing.T) {
 	reg := prometheus.NewRegistry()
 	reg.MustRegister(&testXfrmCollector{xc: c})
 
-	sink := make(chan prometheus.Metric)
-	go func() {
-		err = c.Update(sink)
-		if err != nil {
-			panic(fmt.Errorf("failed to update collector: %s", err))
-		}
-		close(sink)
-	}()
-
 	err = testutil.GatherAndCompare(reg, strings.NewReader(testcase))
 	if err != nil {
 		t.Fatal(err)

go.mod

@@ -27,6 +27,7 @@ require (
 	github.com/prometheus/exporter-toolkit v0.16.0
 	github.com/prometheus/procfs v0.20.1
 	github.com/safchain/ethtool v0.7.0
+	go.uber.org/goleak v1.3.0
 	golang.org/x/sys v0.42.0
 	howett.net/plist v1.0.1
 )