fix: set connection limits for database

common/utils.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"math/rand"
 	"net"
+	"os"
 	"os/exec"
 	"runtime"
 	"strconv"
@@ -177,3 +178,15 @@ func Max(a int, b int) int {
 		return b
 	}
 }
+
+func GetOrDefault(env string, defaultValue int) int {
+	if env == "" || os.Getenv(env) == "" {
+		return defaultValue
+	}
+	num, err := strconv.Atoi(os.Getenv(env))
+	if err != nil {
+		SysError(fmt.Sprintf("failed to parse %s: %s, using default value: %d", env, err.Error(), defaultValue))
+		return defaultValue
+	}
+	return num
+}