Streaming Transfers (#153)

server/transfer/transfer.go

@@ -0,0 +1,128 @@
+package transfer
+
+import (
+	"context"
+	"time"
+
+	"github.com/apex/log"
+	"github.com/mitchellh/colorstring"
+
+	"github.com/pterodactyl/wings/server"
+	"github.com/pterodactyl/wings/system"
+)
+
+// Status represents the current status of a transfer.
+type Status string
+
+// String satisfies the fmt.Stringer interface.
+func (s Status) String() string {
+	return string(s)
+}
+
+const (
+	// StatusPending is the status of a transfer when it is first created.
+	StatusPending Status = "pending"
+	// StatusProcessing is the status of a transfer when it is currently in
+	// progress, such as when the archive is being streamed to the target node.
+	StatusProcessing Status = "processing"
+
+	// StatusCancelling is the status of a transfer when it is in the process of
+	// being cancelled.
+	StatusCancelling Status = "cancelling"
+
+	// StatusCancelled is the final status of a transfer when it has been
+	// cancelled.
+	StatusCancelled Status = "cancelled"
+	// StatusFailed is the final status of a transfer when it has failed.
+	StatusFailed Status = "failed"
+	// StatusCompleted is the final status of a transfer when it has completed.
+	StatusCompleted Status = "completed"
+)
+
+// Transfer represents a transfer of a server from one node to another.
+type Transfer struct {
+	// ctx is the context for the transfer.
+	ctx context.Context
+	// cancel is used to cancel all ongoing transfer operations for the server.
+	cancel *context.CancelFunc
+
+	// Server associated with the transfer.
+	Server *server.Server
+	// status of the transfer.
+	status *system.Atomic[Status]
+
+	// archive is the archive that is being created for the transfer.
+	archive *Archive
+}
+
+// New returns a new transfer instance for the given server.
+func New(ctx context.Context, s *server.Server) *Transfer {
+	ctx, cancel := context.WithCancel(ctx)
+
+	return &Transfer{
+		ctx:    ctx,
+		cancel: &cancel,
+
+		Server: s,
+		status: system.NewAtomic(StatusPending),
+	}
+}
+
+// Context returns the context for the transfer.
+func (t *Transfer) Context() context.Context {
+	return t.ctx
+}
+
+// Cancel cancels the transfer.
+func (t *Transfer) Cancel() {
+	status := t.Status()
+	if status == StatusCancelling ||
+		status == StatusCancelled ||
+		status == StatusCompleted ||
+		status == StatusFailed {
+		return
+	}
+
+	if t.cancel == nil {
+		return
+	}
+
+	t.SetStatus(StatusCancelling)
+	(*t.cancel)()
+}
+
+// Status returns the current status of the transfer.
+func (t *Transfer) Status() Status {
+	return t.status.Load()
+}
+
+// SetStatus sets the status of the transfer.
+func (t *Transfer) SetStatus(s Status) {
+	// TODO: prevent certain status changes from happening.
+	// If we are cancelling, then we can't go back to processing.
+	t.status.Store(s)
+
+	t.Server.Events().Publish(server.TransferStatusEvent, s)
+}
+
+// SendMessage sends a message to the server's console.
+func (t *Transfer) SendMessage(v string) {
+	t.Server.Events().Publish(
+		server.TransferLogsEvent,
+		colorstring.Color("[yellow][bold]"+time.Now().Format(time.RFC1123)+" [Transfer System] [Source Node]:[default] "+v),
+	)
+}
+
+// Error logs an error that occurred on the source node.
+func (t *Transfer) Error(err error, v string) {
+	t.Log().WithError(err).Error(v)
+	t.SendMessage(v)
+}
+
+// Log returns a logger for the transfer.
+func (t *Transfer) Log() *log.Entry {
+	if t.Server == nil {
+		return log.WithField("subsystem", "transfer")
+	}
+	return t.Server.Log().WithField("subsystem", "transfer")
+}