Merge pull request #218 from tendermint/feature/client-proofs

Support non-existence proof

TODO.md

@@ -1,21 +0,0 @@
-Alexis:
-
-* merkle - proof (non-existence - maybe range)
-* intro to light-client and proofs
-light-client proofs:
-* make this sensible -> very tied to merkle proofs and API
-* support new proof types
-
-* expose more proof types in basecoin.Query
-
-
-* merkle - api cleanup (also Bonsai)
-* later: C bindings (to Bonsai?)
-
-
-* crypto-ledger (while ethan gone)
-
-light-client provider:
-* caching checkpoint on Verify
-* cleanup (trim old node)
-

client/commands/query/get.go

@@ -11,6 +11,7 @@ import (
 	wire "github.com/tendermint/go-wire"
 	"github.com/tendermint/go-wire/data"
 	lc "github.com/tendermint/light-client"
+	"github.com/tendermint/light-client/certifiers"
 	"github.com/tendermint/light-client/proofs"
 	"github.com/tendermint/merkleeyes/iavl"
 	"github.com/tendermint/tendermint/rpc/client"
@@ -51,65 +52,93 @@ func Get(key []byte, prove bool) (data.Bytes, uint64, error) {
 		resp, err := node.ABCIQuery("/key", key, false)
 		return data.Bytes(resp.Value), resp.Height, err
 	}
-	val, h, _, err := GetWithProof(key)
+	val, h, _, _, err := GetWithProof(key)
 	return val, h, err
 }
 
 // GetWithProof returns the values stored under a given key at the named
 // height as in Get.  Additionally, it will return a validated merkle
 // proof for the key-value pair if it exists, and all checks pass.
-func GetWithProof(key []byte) (data.Bytes, uint64, *iavl.KeyExistsProof, error) {
-	node := commands.GetNode()
+func GetWithProof(key []byte) (data.Bytes, uint64,
+	*iavl.KeyExistsProof, *iavl.KeyNotExistsProof, error) {
 
-	resp, err := node.ABCIQuery("/key", key, true)
-	if err != nil {
-		return nil, 0, nil, err
-	}
-	ph := int(resp.Height)
-
-	// make sure the proof is the proper height
-	if !resp.Code.IsOK() {
-		return nil, 0, nil, errors.Errorf("Query error %d: %s", resp.Code, resp.Code.String())
-	}
-	// TODO: Handle null proofs
-	if len(resp.Key) == 0 || len(resp.Value) == 0 || len(resp.Proof) == 0 {
-		return nil, 0, nil, lc.ErrNoData()
-	}
-	if ph != 0 && ph != int(resp.Height) {
-		return nil, 0, nil, lc.ErrHeightMismatch(ph, int(resp.Height))
-	}
-
-	check, err := GetCertifiedCheckpoint(ph)
-	if err != nil {
-		return nil, 0, nil, err
-	}
-
-	proof := new(iavl.KeyExistsProof)
-	err = wire.ReadBinaryBytes(resp.Proof, &proof)
-	if err != nil {
-		return nil, 0, nil, err
-	}
-
-	// validate the proof against the certified header to ensure data integrity
-	err = proof.Verify(resp.Key, resp.Value, check.Header.AppHash)
-	if err != nil {
-		return nil, 0, nil, err
-	}
-
-	return data.Bytes(resp.Value), resp.Height, proof, nil
-}
-
-// GetCertifiedCheckpoint gets the signed header for a given height
-// and certifies it.  Returns error if unable to get a proven header.
-func GetCertifiedCheckpoint(h int) (empty lc.Checkpoint, err error) {
-	// here is the certifier, root of all trust
 	node := commands.GetNode()
 	cert, err := commands.GetCertifier()
+	if err != nil {
+		return nil, 0, nil, nil, err
+	}
+	return getWithProof(key, node, cert)
+}
+
+func getWithProof(key []byte, node client.Client, cert certifiers.Certifier) (
+	val data.Bytes, height uint64, eproof *iavl.KeyExistsProof, neproof *iavl.KeyNotExistsProof, err error) {
+
+	resp, err := node.ABCIQuery("/key", key, true)
 	if err != nil {
 		return
 	}
 
-	// get the checkpoint for this height
+	// make sure the proof is the proper height
+	if !resp.Code.IsOK() {
+		err = errors.Errorf("Query error %d: %s", resp.Code, resp.Code.String())
+		return
+	}
+	if len(resp.Key) == 0 || len(resp.Proof) == 0 {
+		err = lc.ErrNoData()
+		return
+	}
+	if resp.Height == 0 {
+		err = errors.New("Height returned is zero")
+		return
+	}
+
+	check, err := getCertifiedCheckpoint(int(resp.Height), node, cert)
+	if err != nil {
+		return
+	}
+
+	if len(resp.Value) > 0 {
+		// The key was found, construct a proof of existence.
+		eproof = new(iavl.KeyExistsProof)
+		err = wire.ReadBinaryBytes(resp.Proof, &eproof)
+		if err != nil {
+			err = errors.Wrap(err, "Error reading proof")
+			return
+		}
+
+		// Validate the proof against the certified header to ensure data integrity.
+		err = eproof.Verify(resp.Key, resp.Value, check.Header.AppHash)
+		if err != nil {
+			err = errors.Wrap(err, "Couldn't verify proof")
+			return
+		}
+		val = data.Bytes(resp.Value)
+	} else {
+		// The key wasn't found, construct a proof of non-existence.
+		neproof = new(iavl.KeyNotExistsProof)
+		err = wire.ReadBinaryBytes(resp.Proof, &neproof)
+		if err != nil {
+			err = errors.Wrap(err, "Error reading proof")
+			return
+		}
+
+		// Validate the proof against the certified header to ensure data integrity.
+		err = neproof.Verify(resp.Key, check.Header.AppHash)
+		if err != nil {
+			err = errors.Wrap(err, "Couldn't verify proof")
+			return
+		}
+		err = lc.ErrNoData()
+	}
+
+	height = resp.Height
+	return
+}
+
+// getCertifiedCheckpoint gets the signed header for a given height
+// and certifies it.  Returns error if unable to get a proven header.
+func getCertifiedCheckpoint(h int, node client.Client,
+	cert certifiers.Certifier) (empty lc.Checkpoint, err error) {
 
 	// FIXME: cannot use cert.GetByHeight for now, as it also requires
 	// Validators and will fail on querying tendermint for non-current height.

client/commands/query/query_test.go

@@ -0,0 +1,131 @@
+package query
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/tendermint/go-wire"
+	lc "github.com/tendermint/light-client"
+	"github.com/tendermint/light-client/certifiers"
+	certclient "github.com/tendermint/light-client/certifiers/client"
+	nm "github.com/tendermint/tendermint/node"
+	"github.com/tendermint/tendermint/rpc/client"
+	rpctest "github.com/tendermint/tendermint/rpc/test"
+	"github.com/tendermint/tendermint/types"
+	"github.com/tendermint/tmlibs/log"
+
+	"github.com/tendermint/basecoin/app"
+	"github.com/tendermint/basecoin/modules/eyes"
+)
+
+var node *nm.Node
+
+func TestMain(m *testing.M) {
+	logger := log.TestingLogger()
+	store, err := app.NewStore("", 0, logger)
+	if err != nil {
+		panic(err)
+	}
+	app := app.NewBasecoin(eyes.NewHandler(), store, logger)
+	node = rpctest.StartTendermint(app)
+
+	code := m.Run()
+
+	node.Stop()
+	node.Wait()
+	os.Exit(code)
+}
+
+func TestAppProofs(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	cl := client.NewLocal(node)
+	client.WaitForHeight(cl, 1, nil)
+
+	k := []byte("my-key")
+	v := []byte("my-value")
+
+	tx := eyes.SetTx{Key: k, Value: v}.Wrap()
+	btx := wire.BinaryBytes(tx)
+	br, err := cl.BroadcastTxCommit(btx)
+	require.NoError(err, "%+v", err)
+	require.EqualValues(0, br.CheckTx.Code, "%#v", br.CheckTx)
+	require.EqualValues(0, br.DeliverTx.Code)
+
+	// This sets up our trust on the node based on some past point.
+	source := certclient.New(cl)
+	seed, err := source.GetByHeight(br.Height - 2)
+	require.NoError(err, "%+v", err)
+	cert := certifiers.NewStatic("my-chain", seed.Validators)
+
+	latest, err := source.GetLatestCommit()
+	require.NoError(err, "%+v", err)
+	rootHash := latest.Header.AppHash
+
+	// Test existing key.
+	var data eyes.Data
+
+	bs, height, proofExists, _, err := getWithProof(k, cl, cert)
+	require.NoError(err, "%+v", err)
+	require.NotNil(proofExists)
+	require.True(height >= uint64(latest.Header.Height))
+
+	err = wire.ReadBinaryBytes(bs, &data)
+	require.NoError(err, "%+v", err)
+	assert.EqualValues(v, data.Value)
+	err = proofExists.Verify(k, bs, rootHash)
+	assert.NoError(err, "%+v", err)
+
+	// Test non-existing key.
+	missing := []byte("my-missing-key")
+	bs, _, proofExists, proofNotExists, err := getWithProof(missing, cl, cert)
+	require.True(lc.IsNoDataErr(err))
+	require.Nil(bs)
+	require.Nil(proofExists)
+	require.NotNil(proofNotExists)
+	err = proofNotExists.Verify(missing, rootHash)
+	assert.NoError(err, "%+v", err)
+	err = proofNotExists.Verify(k, rootHash)
+	assert.Error(err)
+}
+
+func TestTxProofs(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	cl := client.NewLocal(node)
+	client.WaitForHeight(cl, 1, nil)
+
+	tx := eyes.SetTx{Key: []byte("key-a"), Value: []byte("value-a")}.Wrap()
+
+	btx := types.Tx(wire.BinaryBytes(tx))
+	br, err := cl.BroadcastTxCommit(btx)
+	require.NoError(err, "%+v", err)
+	require.EqualValues(0, br.CheckTx.Code, "%#v", br.CheckTx)
+	require.EqualValues(0, br.DeliverTx.Code)
+
+	source := certclient.New(cl)
+	seed, err := source.GetByHeight(br.Height - 2)
+	require.NoError(err, "%+v", err)
+	cert := certifiers.NewStatic("my-chain", seed.Validators)
+
+	// First let's make sure a bogus transaction hash returns a valid non-existence proof.
+	key := types.Tx([]byte("bogus")).Hash()
+	bs, _, proofExists, proofNotExists, err := getWithProof(key, cl, cert)
+	assert.Nil(bs, "value should be nil")
+	require.True(lc.IsNoDataErr(err), "error should signal 'no data'")
+	assert.Nil(proofExists, "existence proof should be nil")
+	require.NotNil(proofNotExists, "non-existence proof shouldn't be nil")
+	err = proofNotExists.Verify(key, proofNotExists.RootHash)
+	require.NoError(err, "%+v", err)
+
+	// Now let's check with the real tx hash.
+	key = btx.Hash()
+	res, err := cl.Tx(key, true)
+	require.NoError(err, "%+v", err)
+	require.NotNil(res)
+	err = res.Proof.Validate(key)
+	assert.NoError(err, "%+v", err)
+}

client/commands/query/tx.go

@@ -46,7 +46,12 @@ func txQueryCmd(cmd *cobra.Command, args []string) error {
 		return showTx(res.Height, res.Tx)
 	}
 
-	check, err := GetCertifiedCheckpoint(res.Height)
+	cert, err := commands.GetCertifier()
+	if err != nil {
+		return err
+	}
+
+	check, err := getCertifiedCheckpoint(res.Height, node, cert)
 	if err != nil {
 		return err
 	}

glide.lock

@@ -1,5 +1,5 @@
-hash: 2848c30b31fb205f846dd7dfca14ebed8a3249cbc5aaa759066b2bab3e4bbf42
-updated: 2017-08-04T15:38:45.048261895+02:00
+hash: 246a02006fc46d91294fba71971c51477241b0ace2989df04d728ae6d09f1013
+updated: 2017-08-09T17:20:03.756445376+02:00
 imports:
 - name: github.com/bgentry/speakeasy
   version: 4aabc24848ce5fd31929f7d1e4ea74d3709c14cd
@@ -135,14 +135,14 @@ imports:
   - data
   - data/base58
 - name: github.com/tendermint/light-client
-  version: fcf4e411583135a1900157b8b0274c41e20ea3a1
+  version: b2afece9635d11e77dd404019b9cf3885d34f4e5
   subpackages:
   - certifiers
   - certifiers/client
   - certifiers/files
   - proofs
 - name: github.com/tendermint/merkleeyes
-  version: 44c4c64c731db5be4261ff3971b01b7e19729419
+  version: 25b700b87a45619cb6bd85330ab4a81b7b7fbb0d
   subpackages:
   - client
   - iavl
@@ -166,6 +166,7 @@ imports:
   - rpc/lib/client
   - rpc/lib/server
   - rpc/lib/types
+  - rpc/test
   - state
   - state/txindex
   - state/txindex/kv

glide.yaml

@@ -29,7 +29,7 @@ import:
   - certifiers/client
   - certifiers/files
 - package: github.com/tendermint/merkleeyes
-  version: unstable
+  version: origin/unstable
   subpackages:
   - client
   - iavl

modules/ibc/commands/query.go

@@ -197,7 +197,7 @@ func packetQueryCmd(cmd *cobra.Command, args []string) error {
 	}
 
 	// output queue, create a post packet
-	bs, height, proof, err := query.GetWithProof(key)
+	bs, height, proof, _, err := query.GetWithProof(key)
 	if err != nil {
 		return err
 	}

state/bonsai.go

@@ -15,6 +15,10 @@ type Bonsai struct {
 	Tree *iavl.IAVLTree
 }
 
+func (b *Bonsai) String() string {
+	return "Bonsai{" + b.Tree.String() + "}"
+}
+
 var _ SimpleDB = &Bonsai{}
 
 // NewBonsai wraps a merkle tree and tags it to track children