rpc rewrite: control RPCs using gRPC + separate RPC for data transfer

transport/ssh: update go-netssh to new version
    => supports CloseWrite and Deadlines
    => build: require Go 1.11 (netssh requires it)

daemon/pruner/pruner.go

@@ -11,7 +11,6 @@ import (
 	"github.com/zrepl/zrepl/replication/pdu"
 	"github.com/zrepl/zrepl/util/envconst"
 	"github.com/zrepl/zrepl/util/watchdog"
-	"github.com/problame/go-streamrpc"
 	"net"
 	"sort"
 	"strings"
@@ -19,14 +18,15 @@ import (
 	"time"
 )
 
-// Try to keep it compatible with gitub.com/zrepl/zrepl/replication.Endpoint
+// Try to keep it compatible with gitub.com/zrepl/zrepl/endpoint.Endpoint
 type History interface {
 	ReplicationCursor(ctx context.Context, req *pdu.ReplicationCursorReq) (*pdu.ReplicationCursorRes, error)
 }
 
+// Try to keep it compatible with gitub.com/zrepl/zrepl/endpoint.Endpoint
 type Target interface {
-	ListFilesystems(ctx context.Context) ([]*pdu.Filesystem, error)
-	ListFilesystemVersions(ctx context.Context, fs string) ([]*pdu.FilesystemVersion, error) // fix depS
+	ListFilesystems(ctx context.Context, req *pdu.ListFilesystemReq) (*pdu.ListFilesystemRes, error)
+	ListFilesystemVersions(ctx context.Context, req *pdu.ListFilesystemVersionsReq) (*pdu.ListFilesystemVersionsRes, error)
 	DestroySnapshots(ctx context.Context, req *pdu.DestroySnapshotsReq) (*pdu.DestroySnapshotsRes, error)
 }
 
@@ -346,7 +346,6 @@ type Error interface {
 }
 
 var _ Error = net.Error(nil)
-var _ Error = streamrpc.Error(nil)
 
 func shouldRetry(e error) bool {
 	if neterr, ok := e.(net.Error); ok {
@@ -381,10 +380,11 @@ func statePlan(a *args, u updater) state {
 		ka = &pruner.Progress
 	})
 
-	tfss, err := target.ListFilesystems(ctx)
+	tfssres, err := target.ListFilesystems(ctx, &pdu.ListFilesystemReq{})
 	if err != nil {
 		return onErr(u, err)
 	}
+	tfss := tfssres.GetFilesystems()
 
 	pfss := make([]*fs, len(tfss))
 	for i, tfs := range tfss {
@@ -398,11 +398,12 @@ func statePlan(a *args, u updater) state {
 		}
 		pfss[i] = pfs
 
-		tfsvs, err := target.ListFilesystemVersions(ctx, tfs.Path)
+		tfsvsres, err := target.ListFilesystemVersions(ctx, &pdu.ListFilesystemVersionsReq{Filesystem: tfs.Path})
 		if err != nil {
 			l.WithError(err).Error("cannot list filesystem versions")
 			return onErr(u, err)
 		}
+		tfsvs := tfsvsres.GetVersions()
 		// no progress here since we could run in a live-lock (must have used target AND receiver before progress)
 
 		pfs.snaps = make([]pruning.Snapshot, 0, len(tfsvs))