初版功能完成

internal/model/session.go

@@ -0,0 +1,78 @@
+package model
+
+import (
+	"fmt"
+	"net/netip"
+	"time"
+)
+
+// SessionStatus is the Server-authoritative Remote Subnet Session state.
+type SessionStatus string
+
+const (
+	SessionCreating      SessionStatus = "CREATING"
+	SessionPreparingSite SessionStatus = "PREPARING_SITE"
+	SessionReady         SessionStatus = "READY"
+	SessionActive        SessionStatus = "ACTIVE"
+	SessionStopping      SessionStatus = "STOPPING"
+	SessionClosed        SessionStatus = "CLOSED"
+	SessionFailed        SessionStatus = "FAILED"
+)
+
+// SessionStatuses is the complete v1 state set.
+var SessionStatuses = [...]SessionStatus{
+	SessionCreating,
+	SessionPreparingSite,
+	SessionReady,
+	SessionActive,
+	SessionStopping,
+	SessionClosed,
+	SessionFailed,
+}
+
+// Valid reports whether the status belongs to the v1 state machine.
+func (s SessionStatus) Valid() bool {
+	switch s {
+	case SessionCreating,
+		SessionPreparingSite,
+		SessionReady,
+		SessionActive,
+		SessionStopping,
+		SessionClosed,
+		SessionFailed:
+		return true
+	default:
+		return false
+	}
+}
+
+// ParseSessionStatus parses and validates a wire/storage Session state.
+func ParseSessionStatus(value string) (SessionStatus, error) {
+	status := SessionStatus(value)
+	if !status.Valid() {
+		return "", fmt.Errorf("invalid session status %q", value)
+	}
+	return status, nil
+}
+
+// SessionCounters are cumulative and use the Engineer point of view.
+type SessionCounters struct {
+	UploadBytes     uint64 `json:"upload_bytes"`
+	DownloadBytes   uint64 `json:"download_bytes"`
+	UploadPackets   uint64 `json:"upload_packets"`
+	DownloadPackets uint64 `json:"download_packets"`
+}
+
+// Session is the Server-authoritative persisted Remote Subnet lifecycle.
+type Session struct {
+	ID             uint64          `json:"session_id,string"`
+	EngineerNodeID string          `json:"engineer_node_id"`
+	SiteNodeID     string          `json:"site_node_id"`
+	Status         SessionStatus   `json:"status"`
+	CIDRs          []netip.Prefix  `json:"cidrs"`
+	CreatedAt      time.Time       `json:"created_at"`
+	ActiveAt       *time.Time      `json:"active_at,omitempty"`
+	ClosedAt       *time.Time      `json:"closed_at,omitempty"`
+	ErrorCode      string          `json:"error_code,omitempty"`
+	Counters       SessionCounters `json:"counters"`
+}