fix(exporter): count only the query result as the exporter coming back (#140)

grpc.NewClient does not dial, so its success marked a dead exporter as
reachable before every query and the next failure warned again: on a node
with a stale socket the warning still repeated every 10s. Only the List
result now decides reachability.

Signed-off-by: mesutoezdil <mesudozdil@gmail.com>

Author: moezdil

internal/pkg/exporter/health.go

@@ -37,8 +37,10 @@ import (
 	pluginapi "k8s.io/kubelet/pkg/apis/deviceplugin/v1beta1"
 )
 
+// healthSocket is the exporter's gRPC socket; tests point it elsewhere.
+var healthSocket = "/var/lib/amd-metrics-exporter/amdgpu_device_metrics_exporter_grpc.socket"
+
 const (
-	healthSocket = "/var/lib/amd-metrics-exporter/amdgpu_device_metrics_exporter_grpc.socket"
 	queryTimeout = 5 * time.Second
 	xcpPrefix    = "amdgpu_xcp_"
 )
@@ -59,7 +61,10 @@ func getGPUHealth() (hMap map[string]string, err error) {
 	conn, err := grpc.NewClient(healthSvcAddress,
 		grpc.WithTransportCredentials(insecure.NewCredentials()),
 	)
-	if logExporterState(err) {
+	// NewClient does not dial, so its success says nothing about the
+	// exporter; only the List result below marks it reachable again
+	if err != nil {
+		logExporterState(err)
 		return
 	}
 

internal/pkg/exporter/health_test.go

@@ -65,3 +65,25 @@ func TestLogExporterStateLogsTransitionsOnce(t *testing.T) {
 		t.Errorf("warnings = %d, want 2", warnings)
 	}
 }
+
+// A stale socket fails every query; NewClient succeeding without dialing must
+// not count as the exporter coming back, or each check warns again.
+func TestStaleSocketWarnsOnce(t *testing.T) {
+	sock := filepath.Join(t.TempDir(), "exporter.socket")
+	if err := os.WriteFile(sock, nil, 0o600); err != nil {
+		t.Fatal(err)
+	}
+	oldSock, oldWarn := healthSocket, warnf
+	warnings := 0
+	healthSocket, warnf = sock, func(string, ...any) { warnings++ }
+	exporterDown.Store(false)
+	t.Cleanup(func() { healthSocket, warnf = oldSock, oldWarn; exporterDown.Store(false) })
+	for range 3 {
+		if _, err := getGPUHealth(); err == nil {
+			t.Fatal("query over a stale socket succeeded")
+		}
+	}
+	if warnings != 1 {
+		t.Errorf("warnings = %d over 3 failed checks, want 1", warnings)
+	}
+}