[#12] services/session: Implement execution service

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/session/executor.go

@@ -0,0 +1,41 @@
+package session
+
+import (
+	"context"
+
+	"github.com/nspcc-dev/neofs-api-go/v2/session"
+	"github.com/pkg/errors"
+)
+
+type ServiceExecutor interface {
+	Create(context.Context, *session.CreateRequestBody) (*session.CreateResponseBody, error)
+}
+
+type executorSvc struct {
+	exec ServiceExecutor
+
+	metaHeader *session.ResponseMetaHeader
+}
+
+// NewExecutionService wraps ServiceExecutor and returns Session Service interface.
+//
+// Passed meta header is attached to all responses.
+func NewExecutionService(exec ServiceExecutor, metaHdr *session.ResponseMetaHeader) session.Service {
+	return &executorSvc{
+		exec:       exec,
+		metaHeader: metaHdr,
+	}
+}
+
+func (s *executorSvc) Create(ctx context.Context, req *session.CreateRequest) (*session.CreateResponse, error) {
+	respBody, err := s.exec.Create(ctx, req.GetBody())
+	if err != nil {
+		return nil, errors.Wrap(err, "could not execute Create request")
+	}
+
+	resp := new(session.CreateResponse)
+	resp.SetBody(respBody)
+	resp.SetMetaHeader(s.metaHeader)
+
+	return resp, nil
+}