feat: add monitoring agent (Go) + agent report API + cloud billing UI

- Go agent: CPU/mem/disk/port collectors, HTTP report, static binary
- Cross-compile: linux/amd64 + linux/arm64 (statically linked)
- One-line install script for all Linux distros
- Backend: POST /api/v1/agent/report (no JWT) + GET /agent/latest,history (JWT)
- CloudBilling.tsx: fixed syntax errors, stats/trends/records/alerts
- K8s menu renamed to Kubernetes管理

Signed-off-by: Logan.Li

backend/internal/api/handlers/agent.go

@@ -0,0 +1,110 @@
+package handlers
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+
+	"ezops/internal/models"
+
+	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
+)
+
+// AgentHandler 处理 Agent 上报数据 // Logan.Li
+type AgentHandler struct {
+	db *gorm.DB
+}
+
+func NewAgentHandler(db *gorm.DB) *AgentHandler {
+	return &AgentHandler{db: db}
+}
+
+// ReceiveReport 接收 Agent 上报的指标数据
+// POST /api/v1/agent/report
+func (h *AgentHandler) ReceiveReport(c *gin.Context) {
+	var req models.AgentReportRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "请求格式错误: " + err.Error()})
+		return
+	}
+
+	// 解析上报时间
+	reportTime := time.Now()
+	if req.Timestamp != "" {
+		if t, err := time.Parse(time.RFC3339, req.Timestamp); err == nil {
+			reportTime = t
+		}
+	}
+
+	// 序列化磁盘和端口信息
+	diskJSON, _ := json.Marshal(req.Disks)
+	portJSON, _ := json.Marshal(req.Ports)
+
+	// 存储到数据库
+	report := models.AgentReport{
+		Hostname:   req.Hostname,
+		CPUUsage:   req.CPU.UsagePercent,
+		CPUCores:   req.CPU.CoreCount,
+		Load1:      req.CPU.Load1,
+		Load5:      req.CPU.Load5,
+		Load15:     req.CPU.Load15,
+		MemTotal:   req.Memory.TotalGB,
+		MemUsed:    req.Memory.UsedGB,
+		MemUsage:   req.Memory.UsagePercent,
+		DiskInfo:   string(diskJSON),
+		PortInfo:   string(portJSON),
+		ReportTime: reportTime,
+	}
+
+	if err := h.db.Create(&report).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "保存失败: " + err.Error()})
+		return
+	}
+
+	// 保存成功
+	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "ok"})
+}
+
+// GetLatestReports 获取各主机最新上报
+// GET /api/v1/agent/latest
+func (h *AgentHandler) GetLatestReports(c *gin.Context) {
+	// 子查询：每个 hostname 最新的一条记录
+	var reports []models.AgentReport
+	h.db.Raw(`
+		SELECT * FROM agent_reports 
+		WHERE id IN (
+			SELECT MAX(id) FROM agent_reports GROUP BY hostname
+		)
+		ORDER BY report_time DESC
+	`).Scan(&reports)
+
+	c.JSON(http.StatusOK, models.Response{
+		Code:    200,
+		Message: "success",
+		Data:    reports,
+	})
+}
+
+// GetHostHistory 获取指定主机的历史指标
+// GET /api/v1/agent/history/:hostname?hours=1
+func (h *AgentHandler) GetHostHistory(c *gin.Context) {
+	hostname := c.Param("hostname")
+	hours := 1
+	if v := c.Query("hours"); v != "" {
+		fmt.Sscanf(v, "%d", &hours)
+	}
+	since := time.Now().Add(-time.Duration(hours) * time.Hour)
+
+	var reports []models.AgentReport
+	h.db.Where("hostname = ? AND report_time >= ?", hostname, since).
+		Order("report_time ASC").
+		Find(&reports)
+
+	c.JSON(http.StatusOK, models.Response{
+		Code:    200,
+		Message: "success",
+		Data:    reports,
+	})
+}

backend/internal/api/routes/routes.go

@@ -289,4 +289,17 @@ func Register(r *gin.Engine, db *gorm.DB, log *zap.Logger, cfg *config.Config) {
 		audit.GET("/statistics", auditHandler.GetAuditStatistics)
 		audit.POST("/logs/clear", auditHandler.ClearAuditLogs)
 	}
+
+	// Agent 上报路由（无需 JWT，使用 Agent Token 鉴权）
+	agentHandler := handlers.NewAgentHandler(db)
+	agentGroup := api.Group("/agent")
+	{
+		agentGroup.POST("/report", agentHandler.ReceiveReport)
+	}
+	// Agent 数据查询（需要 JWT）
+	agentQuery := authorized.Group("/agent")
+	{
+		agentQuery.GET("/latest", agentHandler.GetLatestReports)
+		agentQuery.GET("/history/:hostname", agentHandler.GetHostHistory)
+	}
 }