Fix service monitor connection leak

services.go

@@ -74,6 +74,20 @@ type ServiceHistoryPoint struct {
 	LatencyMS float64 `json:"latencyMs"`
 }
 
+var serviceHTTPTransport = &http.Transport{
+	Proxy:                 http.ProxyFromEnvironment,
+	DialContext:           (&net.Dialer{Timeout: 10 * time.Second, KeepAlive: 30 * time.Second}).DialContext,
+	ForceAttemptHTTP2:     true,
+	MaxIdleConns:          32,
+	MaxIdleConnsPerHost:   2,
+	IdleConnTimeout:       30 * time.Second,
+	TLSHandshakeTimeout:   10 * time.Second,
+	ExpectContinueTimeout: time.Second,
+	TLSClientConfig:       &tls.Config{InsecureSkipVerify: true, MinVersion: tls.VersionTLS12},
+}
+
+var serviceHTTPClient = &http.Client{Transport: serviceHTTPTransport}
+
 func (s *Store) Services() ([]MonitoredService, error) {
 	rows, err := s.db.Query(`SELECT id,name,url,local_address,check_type,expected_code,expected_text,timeout_seconds,enabled FROM services ORDER BY id`)
 	if err != nil {
@@ -296,14 +310,12 @@ func checkServiceEndpoint(v MonitoredService, kind, label, target string) Servic
 			st.Error = strings.TrimSpace(string(out))
 		}
 	default:
-		tr := &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true, MinVersion: tls.VersionTLS12}}
-		client := &http.Client{Transport: tr, Timeout: time.Duration(v.TimeoutSeconds) * time.Second}
 		req, err := http.NewRequestWithContext(ctx, http.MethodGet, target, nil)
 		if err != nil {
 			st.Error = err.Error()
 			break
 		}
-		resp, err := client.Do(req)
+		resp, err := serviceHTTPClient.Do(req)
 		if err != nil {
 			st.Error = err.Error()
 		} else {

services_test.go

@@ -1,6 +1,9 @@
 package main
 
-import "testing"
+import (
+	"testing"
+	"time"
+)
 
 func TestServiceCRUD(t *testing.T) {
 	store, err := openStore(":memory:")
@@ -38,3 +41,15 @@ func TestValidateServiceChecksBothHTTPAddresses(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestHTTPServiceTransportHasBoundedIdlePool(t *testing.T) {
+	if serviceHTTPClient.Transport != serviceHTTPTransport {
+		t.Fatal("проверки сервисов должны использовать общий HTTP transport")
+	}
+	if serviceHTTPTransport.IdleConnTimeout < time.Second {
+		t.Fatal("idle-соединения должны автоматически закрываться")
+	}
+	if serviceHTTPTransport.MaxIdleConnsPerHost < 1 || serviceHTTPTransport.MaxIdleConnsPerHost > 4 {
+		t.Fatalf("небезопасный размер пула на хост: %d", serviceHTTPTransport.MaxIdleConnsPerHost)
+	}
+}