feat: v0.34 健康探针(Architecture B) + Agent v2.1 + 端口监控 + 告警联系人重构

- v0.31: AlertContact 重构(channel_type下拉+webhook_url替代三分立字段)
- v0.32: Agent ProcessTop 增强(cmdline/user/cpu_pct/mem_pct)
- v0.33: 端口监控 Tab(监听端口自动发现+down联动告警)
- v0.34: 健康探针(Agent本地执行HTTP/TCP/Exec→结果随心跳上报)
- Agent新增: ContextSwitch/FD/HealthProbe采集器
- 后端新增: health_probe handler + Agent model扩展
- HostMonitor新增Tab: 健康探针/端口监控

agent/client/http.go

@@ -0,0 +1,140 @@
+// Package client 提供 Agent 与 AIOps 后端通信的共享 HTTP 客户端。
+// Reporter 和 TaskClient 共用此客户端，避免重复实现鉴权、重试、上下文传播。
+//
+// 署名 Logan.Li
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"strings"
+	"time"
+)
+
+const (
+	defaultTimeout = 10 * time.Second
+	maxRetries     = 3
+	userAgent      = "aiops-agent/2.1"
+)
+
+// Client 共享 HTTP 客户端，封装鉴权、路径拼接、重试逻辑。
+type Client struct {
+	baseURL    string
+	token      string
+	httpClient *http.Client
+	Logger     *log.Logger
+}
+
+// New 创建客户端实例。
+func New(server, token string, logger *log.Logger) *Client {
+	return &Client{
+		baseURL:    strings.TrimRight(server, "/"),
+		token:      token,
+		httpClient: &http.Client{Timeout: defaultTimeout},
+		Logger:     logger,
+	}
+}
+
+// Do 执行 HTTP 请求并返回原始响应。调用方负责关闭 resp.Body。
+func (c *Client) Do(ctx context.Context, method, path string, body []byte) (*http.Response, error) {
+	url := c.baseURL + path
+
+	var lastErr error
+	for attempt := 1; attempt <= maxRetries; attempt++ {
+		var reqBody io.Reader
+		if body != nil {
+			reqBody = bytes.NewReader(body)
+		}
+
+		req, err := http.NewRequestWithContext(ctx, method, url, reqBody)
+		if err != nil {
+			return nil, fmt.Errorf("构造请求失败: %w", err)
+		}
+		req.Header.Set("Content-Type", "application/json")
+		req.Header.Set("Accept", "application/json")
+		req.Header.Set("User-Agent", userAgent)
+		if c.token != "" {
+			req.Header.Set("Authorization", "Bearer "+c.token)
+		}
+
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+
+		resp, err := c.httpClient.Do(req)
+		if err != nil {
+			lastErr = err
+			c.Logger.Printf("[http] 请求失败（第%d次） %s %s: %v", attempt, method, path, err)
+			if !sleepWithCtx(ctx, attempt) {
+				return nil, ctx.Err()
+			}
+			continue
+		}
+
+		if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+			return resp, nil
+		}
+
+		// 读取错误响应体
+		errBody, _ := io.ReadAll(io.LimitReader(resp.Body, 1024))
+		resp.Body.Close()
+
+		lastErr = fmt.Errorf("HTTP %d %s %s: %s", resp.StatusCode, method, path, string(errBody))
+
+		// 4xx（除 429）不重试
+		if resp.StatusCode >= 400 && resp.StatusCode < 500 && resp.StatusCode != http.StatusTooManyRequests {
+			return nil, lastErr
+		}
+		c.Logger.Printf("[http] 响应异常（第%d次） %s %s: HTTP %d", attempt, method, path, resp.StatusCode)
+		if !sleepWithCtx(ctx, attempt) {
+			return nil, ctx.Err()
+		}
+	}
+	return nil, lastErr
+}
+
+// DoJSON 执行请求并解析 JSON 响应到 result。自动关闭响应体。
+func (c *Client) DoJSON(ctx context.Context, method, path string, reqBody, result interface{}) error {
+	var bodyBytes []byte
+	if reqBody != nil {
+		var err error
+		bodyBytes, err = json.Marshal(reqBody)
+		if err != nil {
+			return fmt.Errorf("序列化请求体失败: %w", err)
+		}
+	}
+
+	resp, err := c.Do(ctx, method, path, bodyBytes)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if result != nil {
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return fmt.Errorf("读取响应体失败: %w", err)
+		}
+		if err := json.Unmarshal(body, result); err != nil {
+			return fmt.Errorf("解析响应失败: %w", err)
+		}
+	}
+	return nil
+}
+
+// sleepWithCtx 带退避的休眠，可被 context 取消。
+func sleepWithCtx(ctx context.Context, attempt int) bool {
+	timer := time.NewTimer(time.Duration(attempt) * time.Second)
+	defer timer.Stop()
+	select {
+	case <-timer.C:
+		return true
+	case <-ctx.Done():
+		return false
+	}
+}