feat(lb): add WaitForLb method (#212)

Author: jerome-quere

api/lb/v1/lb_utils.go

@@ -0,0 +1,50 @@
+package lb
+
+import (
+	"time"
+
+	"github.com/scaleway/scaleway-sdk-go/internal/async"
+	"github.com/scaleway/scaleway-sdk-go/internal/errors"
+	"github.com/scaleway/scaleway-sdk-go/scw"
+)
+
+// WaitForLbRequest is used by WaitForLb method.
+type WaitForLbRequest struct {
+	LbID    string
+	Region  scw.Region
+	Timeout time.Duration
+}
+
+// WaitForLb waits for the lb to be in a "terminal state" before returning.
+// This function can be used to wait for a lb to be ready for example.
+func (s *API) WaitForLb(req *WaitForLbRequest) (*Lb, error) {
+
+	terminalStatus := map[LbStatus]struct{}{
+		LbStatusReady:   {},
+		LbStatusStopped: {},
+		LbStatusError:   {},
+		LbStatusLocked:  {},
+	}
+
+	lb, err := async.WaitSync(&async.WaitSyncConfig{
+		Get: func() (interface{}, error, bool) {
+			res, err := s.GetLb(&GetLbRequest{
+				LbID:   req.LbID,
+				Region: req.Region,
+			})
+
+			if err != nil {
+				return nil, err, false
+			}
+			_, isTerminal := terminalStatus[res.Status]
+
+			return res, nil, isTerminal
+		},
+		Timeout:          req.Timeout,
+		IntervalStrategy: async.LinearIntervalStrategy(5 * time.Second),
+	})
+	if err != nil {
+		return nil, errors.Wrap(err, "waiting for lb failed")
+	}
+	return lb.(*Lb), nil
+}