feat: add network monitors (ICMP/TCP/HTTP/DNS) (#2266)

Co-authored-by: xiaomiku01 <xiaomiku01@outlook.com>
Co-authored-by: henrygd <hank@henrygd.me>

internal/hub/systems/network_monitors.go

@@ -0,0 +1,58 @@
+package systems
+
+import (
+	"context"
+	"time"
+
+	"github.com/henrygd/beszel"
+	"github.com/henrygd/beszel/internal/common"
+	"github.com/henrygd/beszel/internal/entities/monitor"
+)
+
+// SyncNetworkMonitors sends monitor configurations to the agent.
+func (sys *System) SyncNetworkMonitors(configs []monitor.Config) error {
+	_, err := sys.syncNetworkMonitors(monitor.SyncRequest{Action: monitor.SyncActionReplace, Configs: configs})
+	return err
+}
+
+// UpsertNetworkMonitor sends a single monitor configuration change to the agent.
+func (sys *System) UpsertNetworkMonitor(config monitor.Config, runNow bool) (*monitor.Result, error) {
+	resp, err := sys.syncNetworkMonitors(monitor.SyncRequest{
+		Action: monitor.SyncActionUpsert,
+		Config: config,
+		RunNow: runNow,
+	})
+	if err != nil {
+		return nil, err
+	}
+	if resp.Result == (monitor.Result{}) {
+		return nil, nil
+	}
+	result := resp.Result
+	return &result, nil
+}
+
+// DeleteNetworkMonitor removes a single monitor task from the agent.
+func (sys *System) DeleteNetworkMonitor(id string) error {
+	_, err := sys.syncNetworkMonitors(monitor.SyncRequest{
+		Action: monitor.SyncActionDelete,
+		Config: monitor.Config{ID: id},
+	})
+	return err
+}
+
+func (sys *System) syncNetworkMonitors(req monitor.SyncRequest) (monitor.SyncResponse, error) {
+	if sys.agentVersion.LT(beszel.MinVersionNetworkMonitors) {
+		return monitor.SyncResponse{}, nil
+	}
+	timeout := 5 * time.Second
+	if req.Action == monitor.SyncActionUpsert && req.RunNow {
+		// Allow the probe to finish, including a timeout result, while preserving
+		// the normal request budget for transport and response handling.
+		timeout += monitor.MaxProbeTimeout
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	var result monitor.SyncResponse
+	return result, sys.request(ctx, common.SyncNetworkMonitors, req, &result)
+}