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

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

internal/entities/monitor/monitor.go

@@ -0,0 +1,102 @@
+package monitor
+
+import "time"
+
+// MaxProbeTimeout is the longest agent probe timeout (currently HTTP).
+// Hub requests that run a probe must allow this time in addition to transport overhead.
+const MaxProbeTimeout = 10 * time.Second
+
+type SyncAction uint8
+
+const (
+	// SyncActionReplace indicates a full sync where the provided configs should replace all existing monitors for the system.
+	SyncActionReplace SyncAction = iota
+	// SyncActionUpsert indicates an incremental sync where the provided config should be added or updated.
+	SyncActionUpsert
+	// SyncActionDelete indicates an incremental sync where the provided config should be removed.
+	SyncActionDelete
+)
+
+// Config defines a network monitor task sent from hub to agent.
+type Config struct {
+	// ID is the stable network_monitors record ID generated by the hub.
+	ID       string `cbor:"0,keyasint"`
+	Target   string `cbor:"1,keyasint"`
+	Protocol string `cbor:"2,keyasint"` // "icmp", "tcp", "http", or "dns"
+	Port     uint16 `cbor:"3,keyasint,omitempty"`
+	Interval uint16 `cbor:"4,keyasint"` // seconds
+}
+
+// SyncRequest defines an incremental or full monitor sync request sent to the agent.
+type SyncRequest struct {
+	Action  SyncAction `cbor:"0,keyasint"`
+	Config  Config     `cbor:"1,keyasint,omitempty"`
+	Configs []Config   `cbor:"2,keyasint,omitempty"`
+	RunNow  bool       `cbor:"3,keyasint,omitempty"`
+}
+
+// SyncResponse returns the immediate result for an upsert when requested.
+type SyncResponse struct {
+	Result Result `cbor:"0,keyasint,omitempty"`
+}
+
+// Result holds aggregated monitor results for a single target.
+//
+// 0: avg response in microseconds
+//
+// 1: 1h average response in microseconds
+//
+// 2: min response in microseconds
+//
+// 3: 1h min response in microseconds
+//
+// 4: max response in microseconds
+//
+// 5: 1h max response in microseconds
+//
+// 6: packet loss percentage (0-100)
+//
+// 7: 1h packet loss percentage (0-100)
+type Result struct {
+	AvgResponse   int64   `cbor:"0,keyasint,omitempty"`
+	AvgResponse1h int64   `cbor:"1,keyasint,omitempty"`
+	MinResponse   int64   `cbor:"2,keyasint,omitempty"`
+	MinResponse1h int64   `cbor:"3,keyasint,omitempty"`
+	MaxResponse   int64   `cbor:"4,keyasint,omitempty"`
+	MaxResponse1h int64   `cbor:"5,keyasint,omitempty"`
+	PacketLoss    float64 `cbor:"6,keyasint,omitempty"`
+	PacketLoss1h  float64 `cbor:"7,keyasint,omitempty"`
+	// LastProbeAt is the latest completed probe's Unix timestamp in milliseconds.
+	LastProbeAt int64 `cbor:"8,keyasint"`
+	// SampleCount includes all completed probes since this monitor started.
+	// Used for alert warm-up even when the interval is longer than 20 minutes.
+	SampleCount int64 `cbor:"9,keyasint,omitempty"`
+	// Counts and sum cover the current response window (or latest-sample
+	// fallback), not the hourly window or lifetime SampleCount.
+	TotalCount   int64 `cbor:"10,keyasint"`
+	SuccessCount int64 `cbor:"11,keyasint"`
+	ResponseSum  int64 `cbor:"12,keyasint"`
+}
+
+// Stats holds response times in microseconds and packet loss percentage (0-100).
+type Stats struct {
+	ResAvg       float64 `json:"res_avg" db:"-"` // Derived for display; not stored.
+	ResMin       float64 `json:"res_min" db:"res_min"`
+	ResMax       float64 `json:"res_max" db:"res_max"`
+	Loss         float64 `json:"loss" db:"-"` // Derived for display; not stored.
+	TotalCount   int64   `json:"-" db:"total_count"`
+	SuccessCount int64   `json:"-" db:"success_count"`
+	ResponseSum  int64   `json:"-" db:"res_sum"`
+}
+
+func (s Stats) FromResult(result Result) Stats {
+	return Stats{
+		ResAvg:       float64(result.AvgResponse),
+		ResMin:       float64(result.MinResponse),
+		ResMax:       float64(result.MaxResponse),
+		Loss:         result.PacketLoss,
+		TotalCount:   result.TotalCount,
+		SuccessCount: result.SuccessCount,
+		ResponseSum:  result.ResponseSum,
+	}
+}

internal/entities/system/system.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/henrygd/beszel/internal/entities/container"
+	"github.com/henrygd/beszel/internal/entities/monitor"
 	"github.com/henrygd/beszel/internal/entities/systemd"
 )
 
@@ -210,5 +211,6 @@ type CombinedData struct {
 	Details         *Details           `cbor:"4,keyasint,omitempty"`
 	// SystemdServicesUpdated distinguishes a fresh empty snapshot from a response
 	// that omitted systemd data (for example, a short-cache dashboard request).
-	SystemdServicesUpdated bool `json:"systemdUpdated,omitempty" cbor:"5,keyasint,omitempty"`
+	SystemdServicesUpdated bool                      `json:"systemdUpdated,omitempty" cbor:"5,keyasint,omitempty"`
+	Monitors               map[string]monitor.Result `cbor:"6,keyasint"`
 }