Make pinset sharding deterministic

Making this deterministic keeps us from creating an exponential amount
of objects as the number of pins in the set increases.

License: MIT
Signed-off-by: Jeromy <jeromyj@gmail.com>

set.go

@@ -3,7 +3,6 @@ package pin
 import (
 	"bytes"
 	"context"
-	"crypto/rand"
 	"encoding/binary"
 	"errors"
 	"fmt"
@@ -26,14 +25,6 @@ const (
 	maxItems = 8192
 )
 
-func randomSeed() (uint32, error) {
-	var buf [4]byte
-	if _, err := rand.Read(buf[:]); err != nil {
-		return 0, err
-	}
-	return binary.LittleEndian.Uint32(buf[:]), nil
-}
-
 func hash(seed uint32, c *cid.Cid) uint32 {
 	var buf [4]byte
 	binary.LittleEndian.PutUint32(buf[:], seed)
@@ -63,11 +54,7 @@ func (s sortByHash) Swap(a, b int) {
 	s.links[a], s.links[b] = s.links[b], s.links[a]
 }
 
-func storeItems(ctx context.Context, dag merkledag.DAGService, estimatedLen uint64, iter itemIterator, internalKeys keyObserver) (*merkledag.ProtoNode, error) {
-	seed, err := randomSeed()
-	if err != nil {
-		return nil, err
-	}
+func storeItems(ctx context.Context, dag merkledag.DAGService, estimatedLen uint64, depth uint32, iter itemIterator, internalKeys keyObserver) (*merkledag.ProtoNode, error) {
 	links := make([]*node.Link, 0, defaultFanout+maxItems)
 	for i := 0; i < defaultFanout; i++ {
 		links = append(links, &node.Link{Cid: emptyKey})
@@ -82,7 +69,7 @@ func storeItems(ctx context.Context, dag merkledag.DAGService, estimatedLen uint
 	hdr := &pb.Set{
 		Version: proto.Uint32(1),
 		Fanout:  proto.Uint32(defaultFanout),
-		Seed:    proto.Uint32(seed),
+		Seed:    proto.Uint32(depth),
 	}
 	if err := writeHdr(n, hdr); err != nil {
 		return nil, err
@@ -129,7 +116,7 @@ func storeItems(ctx context.Context, dag merkledag.DAGService, estimatedLen uint
 		if !ok {
 			break
 		}
-		h := hash(seed, k) % defaultFanout
+		h := hash(depth, k) % defaultFanout
 		hashed[h] = append(hashed[h], k)
 	}
 
@@ -142,7 +129,7 @@ func storeItems(ctx context.Context, dag merkledag.DAGService, estimatedLen uint
 		childIter := getCidListIterator(items)
 
 		// recursively create a pinset from the items for this bucket index
-		child, err := storeItems(ctx, dag, uint64(len(items)), childIter, internalKeys)
+		child, err := storeItems(ctx, dag, uint64(len(items)), depth+1, childIter, internalKeys)
 		if err != nil {
 			return nil, err
 		}
@@ -296,7 +283,7 @@ func getCidListIterator(cids []*cid.Cid) itemIterator {
 func storeSet(ctx context.Context, dag merkledag.DAGService, cids []*cid.Cid, internalKeys keyObserver) (*merkledag.ProtoNode, error) {
 	iter := getCidListIterator(cids)
 
-	n, err := storeItems(ctx, dag, uint64(len(cids)), iter, internalKeys)
+	n, err := storeItems(ctx, dag, uint64(len(cids)), 0, iter, internalKeys)
 	if err != nil {
 		return nil, err
 	}

set_test.go

@@ -2,40 +2,75 @@ package pin
 
 import (
 	"context"
-	"fmt"
-	"os"
+	"encoding/binary"
 	"testing"
 
+	blockstore "github.com/ipfs/go-ipfs/blocks/blockstore"
+	bserv "github.com/ipfs/go-ipfs/blockservice"
+	offline "github.com/ipfs/go-ipfs/exchange/offline"
 	dag "github.com/ipfs/go-ipfs/merkledag"
-	mdtest "github.com/ipfs/go-ipfs/merkledag/test"
 
+	ds "gx/ipfs/QmRWDav6mzWseLWeYfVd5fvUKiVe9xNH29YfMF438fG364/go-datastore"
+	dsq "gx/ipfs/QmRWDav6mzWseLWeYfVd5fvUKiVe9xNH29YfMF438fG364/go-datastore/query"
 	cid "gx/ipfs/QmcTcsTvfaeEBRFo1TkFgT8sRmgi1n1LTZpecfVP8fzpGD/go-cid"
 )
 
 func ignoreCids(_ *cid.Cid) {}
 
-func TestSet(t *testing.T) {
-	ds := mdtest.Mock()
-	limit := 10000 // 10000 reproduces the pinloss issue fairly reliably
+func objCount(d ds.Datastore) int {
+	q := dsq.Query{KeysOnly: true}
+	res, err := d.Query(q)
+	if err != nil {
+		panic(err)
+	}
+
+	var count int
+	for {
+		_, ok := res.NextSync()
+		if !ok {
+			break
+		}
 
-	if os.Getenv("STRESS_IT_OUT_YO") != "" {
-		limit = 10000000
+		count++
 	}
+	return count
+}
+
+func TestSet(t *testing.T) {
+	dst := ds.NewMapDatastore()
+	bstore := blockstore.NewBlockstore(dst)
+	ds := dag.NewDAGService(bserv.New(bstore, offline.Exchange(bstore)))
+
+	// this value triggers the creation of a recursive shard.
+	// If the recursive sharding is done improperly, this will result in
+	// an infinite recursion and crash (OOM)
+	limit := uint32((defaultFanout * maxItems) + 1)
+
 	var inputs []*cid.Cid
-	for i := 0; i < limit; i++ {
-		c, err := ds.Add(dag.NodeWithData([]byte(fmt.Sprint(i))))
+	buf := make([]byte, 4)
+	for i := uint32(0); i < limit; i++ {
+		binary.BigEndian.PutUint32(buf, i)
+		c := dag.NewRawNode(buf).Cid()
+		inputs = append(inputs, c)
+	}
+
+	_, err := storeSet(context.Background(), ds, inputs[:len(inputs)-1], ignoreCids)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-		inputs = append(inputs, c)
-	}
+	objs1 := objCount(dst)
 
 	out, err := storeSet(context.Background(), ds, inputs, ignoreCids)
 	if err != nil {
 		t.Fatal(err)
 	}
 
+	objs2 := objCount(dst)
+	if objs2-objs1 > 2 {
+		t.Fatal("set sharding does not appear to be deterministic")
+	}
+
 	// weird wrapper node because loadSet expects us to pass an
 	// object pointing to multiple named sets
 	setroot := &dag.ProtoNode{}
@@ -49,7 +84,7 @@ func TestSet(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if len(outset) != limit {
+	if uint32(len(outset)) != limit {
 		t.Fatal("got wrong number", len(outset), limit)
 	}