[#321] platformtest: minimal integration tests for package replication

# Conflicts:
#	platformtest/tests/generated_cases.go

platformtest/tests/generated_cases.go

@@ -13,6 +13,8 @@ var Cases = []Case{BatchDestroy,
 	ListFilesystemVersionsUserrefs,
 	ListFilesystemVersionsZeroExistIsNotAnError,
 	ListFilesystemsNoFilter,
+	ReplicationIncrementalIsPossibleIfCommonSnapshotIsDestroyed,
+	ReplicationIsResumableFullSend,
 	ResumableRecvAndTokenHandling,
 	ResumeTokenParsing,
 	SendArgsValidationEncryptedSendOfUnencryptedDatasetForbidden,

platformtest/tests/replication.go

@@ -0,0 +1,207 @@
+package tests
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"path"
+
+	"github.com/kr/pretty"
+	"github.com/stretchr/testify/require"
+	"github.com/zrepl/zrepl/daemon/filters"
+	"github.com/zrepl/zrepl/endpoint"
+	"github.com/zrepl/zrepl/platformtest"
+	"github.com/zrepl/zrepl/replication"
+	"github.com/zrepl/zrepl/replication/logic"
+	"github.com/zrepl/zrepl/replication/logic/pdu"
+	"github.com/zrepl/zrepl/replication/report"
+	"github.com/zrepl/zrepl/util/limitio"
+	"github.com/zrepl/zrepl/zfs"
+)
+
+// mimics the replication invocations of an active-side job
+// for a single sender-receiver filesystem pair
+//
+// each invocation of method Do results in the construction
+// of a new sender and receiver instance and one blocking invocation
+// of the replication engine without encryption
+type replicationInvocation struct {
+	sjid, rjid      endpoint.JobID
+	sfs             string
+	rfsRoot         string
+	interceptSender func(e *endpoint.Sender) logic.Sender
+}
+
+func (i replicationInvocation) Do(ctx *platformtest.Context) *report.Report {
+
+	if i.interceptSender == nil {
+		i.interceptSender = func(e *endpoint.Sender) logic.Sender { return e }
+	}
+
+	sfilter := filters.NewDatasetMapFilter(1, true)
+	err := sfilter.Add(i.sfs, "ok")
+	require.NoError(ctx, err)
+	sender := i.interceptSender(endpoint.NewSender(endpoint.SenderConfig{
+		FSF:     sfilter.AsFilter(),
+		Encrypt: &zfs.NilBool{B: false},
+		JobID:   i.sjid,
+	}))
+	receiver := endpoint.NewReceiver(endpoint.ReceiverConfig{
+		JobID:                      i.rjid,
+		AppendClientIdentity:       false,
+		RootWithoutClientComponent: mustDatasetPath(i.rfsRoot),
+		UpdateLastReceivedHold:     true,
+	})
+	plannerPolicy := logic.PlannerPolicy{
+		EncryptedSend: logic.TriFromBool(false),
+	}
+
+	report, wait := replication.Do(
+		ctx,
+		logic.NewPlanner(nil, nil, sender, receiver, plannerPolicy),
+	)
+	wait(true)
+	return report()
+}
+
+func (i replicationInvocation) ReceiveSideFilesystem() string {
+	return path.Join(i.rfsRoot, i.sfs)
+}
+
+func ReplicationIncrementalIsPossibleIfCommonSnapshotIsDestroyed(ctx *platformtest.Context) {
+
+	platformtest.Run(ctx, platformtest.PanicErr, ctx.RootDataset, `
+		CREATEROOT
+		+  "sender"
+		+  "sender@1"
+		+  "receiver"
+		R  zfs create -p "${ROOTDS}/receiver/${ROOTDS}"
+	`)
+
+	sjid := endpoint.MustMakeJobID("sender-job")
+	rjid := endpoint.MustMakeJobID("receiver-job")
+
+	sfs := ctx.RootDataset + "/sender"
+	rfsRoot := ctx.RootDataset + "/receiver"
+	snap1 := fsversion(ctx, sfs, "@1")
+
+	rep := replicationInvocation{
+		sjid:    sjid,
+		rjid:    rjid,
+		sfs:     sfs,
+		rfsRoot: rfsRoot,
+	}
+	rfs := rep.ReceiveSideFilesystem()
+
+	// first replication
+	report := rep.Do(ctx)
+	ctx.Logf("\n%s", pretty.Sprint(report))
+
+	// assert @1 exists on receiver
+	_ = fsversion(ctx, rfs, "@1")
+
+	// cut off the common base between sender and receiver
+	// (replication engine guarantees resumability through bookmarks)
+	err := zfs.ZFSDestroy(ctx, snap1.FullPath(sfs))
+	require.NoError(ctx, err)
+
+	// assert that the replication cursor has been created
+	snap1CursorName, err := endpoint.ReplicationCursorBookmarkName(sfs, snap1.Guid, sjid)
+	require.NoError(ctx, err)
+	snap1CursorInfo, err := zfs.ZFSGetFilesystemVersion(ctx, sfs+"#"+snap1CursorName)
+	require.NoError(ctx, err)
+	require.True(ctx, snap1CursorInfo.IsBookmark())
+
+	// second replication of a new snapshot, should use the cursor
+	mustSnapshot(ctx, sfs+"@2")
+	report = rep.Do(ctx)
+	ctx.Logf("\n%s", pretty.Sprint(report))
+	_ = fsversion(ctx, rfs, "@2")
+
+}
+
+type PartialSender struct {
+	*endpoint.Sender
+	failAfterByteCount int64
+}
+
+var _ logic.Sender = (*PartialSender)(nil)
+
+func (s *PartialSender) Send(ctx context.Context, r *pdu.SendReq) (r1 *pdu.SendRes, r2 io.ReadCloser, r3 error) {
+	r1, r2, r3 = s.Sender.Send(ctx, r)
+	r2 = limitio.ReadCloser(r2, s.failAfterByteCount)
+	return r1, r2, r3
+}
+
+func ReplicationIsResumableFullSend(ctx *platformtest.Context) {
+
+	platformtest.Run(ctx, platformtest.PanicErr, ctx.RootDataset, `
+		CREATEROOT
+		+  "sender"
+		+  "receiver"
+		R  zfs create -p "${ROOTDS}/receiver/${ROOTDS}"
+	`)
+
+	sjid := endpoint.MustMakeJobID("sender-job")
+	rjid := endpoint.MustMakeJobID("receiver-job")
+
+	sfs := ctx.RootDataset + "/sender"
+	rfsRoot := ctx.RootDataset + "/receiver"
+
+	sfsmp, err := zfs.ZFSGetMountpoint(ctx, sfs)
+	require.NoError(ctx, err)
+	require.True(ctx, sfsmp.Mounted)
+
+	writeDummyData(path.Join(sfsmp.Mountpoint, "dummy.data"), 1<<22)
+	mustSnapshot(ctx, sfs+"@1")
+	snap1 := fsversion(ctx, sfs, "@1")
+
+	rep := replicationInvocation{
+		sjid:    sjid,
+		rjid:    rjid,
+		sfs:     sfs,
+		rfsRoot: rfsRoot,
+		interceptSender: func(e *endpoint.Sender) logic.Sender {
+			return &PartialSender{Sender: e, failAfterByteCount: 1 << 20}
+		},
+	}
+	rfs := rep.ReceiveSideFilesystem()
+
+	for i := 2; i < 10; i++ {
+		report := rep.Do(ctx)
+		ctx.Logf("\n%s", pretty.Sprint(report))
+
+		// always attempt to destroy the incremental source
+		err := zfs.ZFSDestroy(ctx, snap1.FullPath(sfs))
+		if i < 4 {
+			// we configured the PartialSender to fail after 1<<20 bytes
+			// and we wrote dummy data 1<<22 bytes, thus at least
+			// for the first 4 times this should not be possible
+			// due to step holds
+			require.Error(ctx, err)
+			require.Contains(ctx, err.Error(), "dataset is busy")
+		}
+
+		// and create some additional snapshots that could
+		// confuse a naive implementation that doesn't take into
+		// account resume state when planning replication
+		if i == 2 || i == 3 {
+			// no significant size to avoid making this test run longer than necessary
+			mustSnapshot(ctx, fmt.Sprintf("%s@%d", sfs, i))
+		}
+
+		require.Len(ctx, report.Attempts, 1)
+		require.Nil(ctx, report.Attempts[0].PlanError)
+		require.Len(ctx, report.Attempts[0].Filesystems, 1)
+		if len(report.Attempts[0].Filesystems[0].Steps) == 0 {
+			break
+		}
+	}
+
+	// make sure all the filesystem versions we created
+	// were replicated by the replication loop
+	_ = fsversion(ctx, rfs, "@1")
+	_ = fsversion(ctx, rfs, "@2")
+	_ = fsversion(ctx, rfs, "@3")
+
+}

replication/logic/replication_logic.go

@@ -287,7 +287,10 @@ func (p *Planner) doPlanning(ctx context.Context) ([]*Filesystem, error) {
 			}
 		}
 
-		ctr := p.promBytesReplicated.WithLabelValues(fs.Path)
+		var ctr prometheus.Counter
+		if p.promBytesReplicated != nil {
+			ctr = p.promBytesReplicated.WithLabelValues(fs.Path)
+		}
 
 		q = append(q, &Filesystem{
 			sender:                 p.sender,
@@ -594,7 +597,9 @@ func (s *Step) doReplication(ctx context.Context) error {
 	s.byteCounterMtx.Unlock()
 	defer func() {
 		defer s.byteCounterMtx.Lock().Unlock()
-		s.parent.promBytesReplicated.Add(float64(s.byteCounter.Count()))
+		if s.parent.promBytesReplicated != nil {
+			s.parent.promBytesReplicated.Add(float64(s.byteCounter.Count()))
+		}
 	}()
 
 	rr := &pdu.ReceiveReq{

zfs/zfs.go

@@ -454,7 +454,7 @@ func (s *SendStream) killAndWait(precedingReadErr error) error {
 			WaitErr: exitErr,
 		}
 	} else {
-		s.opErr = fmt.Errorf("zfs send exited with status code 0")
+		s.opErr = precedingReadErr
 	}
 
 	// detect the edge where we're called from s.Read
@@ -1014,7 +1014,9 @@ func ZFSRecv(ctx context.Context, fs string, v *ZFSSendArgVersion, stream io.Rea
 		snaps, err := ZFSListFilesystemVersions(ctx, fsdp, ListFilesystemVersionsOptions{
 			Types: Snapshots,
 		})
-		if err != nil {
+		if _, ok := err.(*DatasetDoesNotExist); ok {
+			snaps = []FilesystemVersion{}
+		} else if err != nil {
 			return fmt.Errorf("cannot list versions for rollback for forced receive: %s", err)
 		}
 		sort.Slice(snaps, func(i, j int) bool {