chainntnfs: add height hint cache interfaces and channeldb implementation

In this commit, we introduce two new interfaces: SpendHintCache and
ConfirmHintCache for a height hint cache. The SpendHintCache is
responsible for maintaining the earliest height at which an outpoint
could have been spent within the chain, while the ConfirmHintCache is
responsible for maintaining the earliest height at which a transaction
confirms within the chain. We also add an implementation of these
interfaces with a single struct HeightHintCache, backed by a channeldb
instance, which will cary the duties of the interfaces above.
This commit is contained in:
Wilmer Paulino 2018-05-21 11:47:39 -04:00
parent 6c903393e5
commit b78cd533f2
No known key found for this signature in database
GPG Key ID: 6DF57B9F9514972F
2 changed files with 445 additions and 0 deletions

@ -0,0 +1,297 @@
package chainntnfs
import (
"bytes"
"errors"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/wire"
bolt "github.com/coreos/bbolt"
"github.com/lightningnetwork/lnd/channeldb"
)
const (
// dbName is the default name of the database storing the height hints.
dbName = "heighthint.db"
// dbFilePermission is the default permission of the database file
// storing the height hints.
dbFilePermission = 0600
)
var (
// spendHintBucket is the name of the bucket which houses the height
// hint for outpoints. Each height hint represents the earliest height
// at which its corresponding outpoint could have been spent within.
spendHintBucket = []byte("spend-hints")
// confirmHintBucket is the name of the bucket which houses the height
// hints for transactions. Each height hint represents the earliest
// height at which its corresponding transaction could have been
// confirmed within.
confirmHintBucket = []byte("confirm-hints")
// ErrCorruptedHeightHintCache indicates that the on-disk bucketing
// structure has altered since the height hint cache instance was
// initialized.
ErrCorruptedHeightHintCache = errors.New("height hint cache has been " +
"corrupted")
// ErrSpendHintNotFound is an error returned when a spend hint for an
// outpoint was not found.
ErrSpendHintNotFound = errors.New("spend hint not found")
// ErrConfirmHintNotFound is an error returned when a confirm hint for a
// transaction was not found.
ErrConfirmHintNotFound = errors.New("confirm hint not found")
)
// SpendHintCache is an interface whose duty is to cache spend hints for
// outpoints. A spend hint is defined as the earliest height in the chain at
// which an outpoint could have been spent within.
type SpendHintCache interface {
// CommitSpendHint commits a spend hint for the outpoints to the cache.
CommitSpendHint(height uint32, ops ...wire.OutPoint) error
// QuerySpendHint returns the latest spend hint for an outpoint.
// ErrSpendHintNotFound is returned if a spend hint does not exist
// within the cache for the outpoint.
QuerySpendHint(op wire.OutPoint) (uint32, error)
// PurgeSpendHint removes the spend hint for the outpoints from the
// cache.
PurgeSpendHint(ops ...wire.OutPoint) error
}
// ConfirmHintCache is an interface whose duty is to cache confirm hints for
// transactions. A confirm hint is defined as the earliest height in the chain
// at which a transaction could have been included in a block.
type ConfirmHintCache interface {
// CommitConfirmHint commits a confirm hint for the transactions to the
// cache.
CommitConfirmHint(height uint32, txids ...chainhash.Hash) error
// QueryConfirmHint returns the latest confirm hint for a transaction
// hash. ErrConfirmHintNotFound is returned if a confirm hint does not
// exist within the cache for the transaction hash.
QueryConfirmHint(txid chainhash.Hash) (uint32, error)
// PurgeConfirmHint removes the confirm hint for the transactions from
// the cache.
PurgeConfirmHint(txids ...chainhash.Hash) error
}
// HeightHintCache is an implementation of the SpendHintCache and
// ConfirmHintCache interfaces backed by a channeldb DB instance where the hints
// will be stored.
type HeightHintCache struct {
db *channeldb.DB
}
// Compile-time checks to ensure HeightHintCache satisfies the SpendHintCache
// and ConfirmHintCache interfaces.
var _ SpendHintCache = (*HeightHintCache)(nil)
var _ ConfirmHintCache = (*HeightHintCache)(nil)
// NewHeightHintCache returns a new height hint cache backed by a database.
func NewHeightHintCache(db *channeldb.DB) (*HeightHintCache, error) {
cache := &HeightHintCache{db}
if err := cache.initBuckets(); err != nil {
return nil, err
}
return cache, nil
}
// initBuckets ensures that the primary buckets used by the circuit are
// initialized so that we can assume their existence after startup.
func (c *HeightHintCache) initBuckets() error {
return c.db.Update(func(tx *bolt.Tx) error {
_, err := tx.CreateBucketIfNotExists(spendHintBucket)
if err != nil {
return err
}
_, err = tx.CreateBucketIfNotExists(confirmHintBucket)
return err
})
}
// CommitSpendHint commits a spend hint for the outpoints to the cache.
func (c *HeightHintCache) CommitSpendHint(height uint32, ops ...wire.OutPoint) error {
Log.Tracef("Updating spend hint to height %d for %v", height, ops)
return c.db.Batch(func(tx *bolt.Tx) error {
spendHints := tx.Bucket(spendHintBucket)
if spendHints == nil {
return ErrCorruptedHeightHintCache
}
var hint bytes.Buffer
if err := channeldb.WriteElement(&hint, height); err != nil {
return err
}
for _, op := range ops {
var outpoint bytes.Buffer
err := channeldb.WriteElement(&outpoint, op)
if err != nil {
return err
}
err = spendHints.Put(outpoint.Bytes(), hint.Bytes())
if err != nil {
return err
}
}
return nil
})
}
// QuerySpendHint returns the latest spend hint for an outpoint.
// ErrSpendHintNotFound is returned if a spend hint does not exist within the
// cache for the outpoint.
func (c *HeightHintCache) QuerySpendHint(op wire.OutPoint) (uint32, error) {
var hint uint32
err := c.db.View(func(tx *bolt.Tx) error {
spendHints := tx.Bucket(spendHintBucket)
if spendHints == nil {
return ErrCorruptedHeightHintCache
}
var outpoint bytes.Buffer
if err := channeldb.WriteElement(&outpoint, op); err != nil {
return err
}
spendHint := spendHints.Get(outpoint.Bytes())
if spendHint == nil {
return ErrSpendHintNotFound
}
return channeldb.ReadElement(bytes.NewReader(spendHint), &hint)
})
if err != nil {
return 0, err
}
return hint, nil
}
// PurgeSpendHint removes the spend hint for the outpoints from the cache.
func (c *HeightHintCache) PurgeSpendHint(ops ...wire.OutPoint) error {
Log.Tracef("Removing spend hints for %v", ops)
return c.db.Batch(func(tx *bolt.Tx) error {
spendHints := tx.Bucket(spendHintBucket)
if spendHints == nil {
return ErrCorruptedHeightHintCache
}
for _, op := range ops {
var outpoint bytes.Buffer
err := channeldb.WriteElement(&outpoint, op)
if err != nil {
return err
}
err = spendHints.Delete(outpoint.Bytes())
if err != nil {
return err
}
}
return nil
})
}
// CommitConfirmHint commits a confirm hint for the transactions to the cache.
func (c *HeightHintCache) CommitConfirmHint(height uint32, txids ...chainhash.Hash) error {
Log.Tracef("Updating confirm hints to height %d for %v", height, txids)
return c.db.Batch(func(tx *bolt.Tx) error {
confirmHints := tx.Bucket(confirmHintBucket)
if confirmHints == nil {
return ErrCorruptedHeightHintCache
}
var hint bytes.Buffer
if err := channeldb.WriteElement(&hint, height); err != nil {
return err
}
for _, txid := range txids {
var txHash bytes.Buffer
err := channeldb.WriteElement(&txHash, txid)
if err != nil {
return err
}
err = confirmHints.Put(txHash.Bytes(), hint.Bytes())
if err != nil {
return err
}
}
return nil
})
}
// QueryConfirmHint returns the latest confirm hint for a transaction hash.
// ErrConfirmHintNotFound is returned if a confirm hint does not exist within
// the cache for the transaction hash.
func (c *HeightHintCache) QueryConfirmHint(txid chainhash.Hash) (uint32, error) {
var hint uint32
err := c.db.View(func(tx *bolt.Tx) error {
confirmHints := tx.Bucket(confirmHintBucket)
if confirmHints == nil {
return ErrCorruptedHeightHintCache
}
var txHash bytes.Buffer
if err := channeldb.WriteElement(&txHash, txid); err != nil {
return err
}
confirmHint := confirmHints.Get(txHash.Bytes())
if confirmHint == nil {
return ErrConfirmHintNotFound
}
return channeldb.ReadElement(bytes.NewReader(confirmHint), &hint)
})
if err != nil {
return 0, err
}
return hint, nil
}
// PurgeConfirmHint removes the confirm hint for the transactions from the
// cache.
func (c *HeightHintCache) PurgeConfirmHint(txids ...chainhash.Hash) error {
Log.Tracef("Removing confirm hints for %v", txids)
return c.db.Batch(func(tx *bolt.Tx) error {
confirmHints := tx.Bucket(confirmHintBucket)
if confirmHints == nil {
return ErrCorruptedHeightHintCache
}
for _, txid := range txids {
var txHash bytes.Buffer
err := channeldb.WriteElement(&txHash, txid)
if err != nil {
return err
}
err = confirmHints.Delete(txHash.Bytes())
if err != nil {
return err
}
}
return nil
})
}

@ -0,0 +1,148 @@
package chainntnfs
import (
"bytes"
"io/ioutil"
"testing"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/wire"
"github.com/lightningnetwork/lnd/channeldb"
)
func initHintCache(t *testing.T) *HeightHintCache {
t.Helper()
tempDir, err := ioutil.TempDir("", "kek")
if err != nil {
t.Fatalf("unable to create temp dir: %v", err)
}
db, err := channeldb.Open(tempDir)
if err != nil {
t.Fatalf("unable to create db: %v", err)
}
hintCache, err := NewHeightHintCache(db)
if err != nil {
t.Fatalf("unable to create hint cache: %v", err)
}
return hintCache
}
// TestHeightHintCacheConfirms ensures that the height hint cache properly
// caches confirm hints for transactions.
func TestHeightHintCacheConfirms(t *testing.T) {
t.Parallel()
hintCache := initHintCache(t)
// Querying for a transaction hash not found within the cache should
// return an error indication so.
var unknownHash chainhash.Hash
_, err := hintCache.QueryConfirmHint(unknownHash)
if err != ErrConfirmHintNotFound {
t.Fatalf("expected ErrConfirmHintNotFound, got: %v", err)
}
// Now, we'll create some transaction hashes and commit them to the
// cache with the same confirm hint.
const height = 100
const numHashes = 5
txHashes := make([]chainhash.Hash, numHashes)
for i := 0; i < numHashes; i++ {
var txHash chainhash.Hash
copy(txHash[:], bytes.Repeat([]byte{byte(i)}, 32))
txHashes[i] = txHash
}
if err := hintCache.CommitConfirmHint(height, txHashes...); err != nil {
t.Fatalf("unable to add entries to cache: %v", err)
}
// With the hashes committed, we'll now query the cache to ensure that
// we're able to properly retrieve the confirm hints.
for _, txHash := range txHashes {
confirmHint, err := hintCache.QueryConfirmHint(txHash)
if err != nil {
t.Fatalf("unable to query for hint: %v", err)
}
if confirmHint != height {
t.Fatalf("expected confirm hint %d, got %d", height,
confirmHint)
}
}
// We'll also attempt to purge all of them in a single database
// transaction.
if err := hintCache.PurgeConfirmHint(txHashes...); err != nil {
t.Fatalf("unable to remove confirm hints: %v", err)
}
// Finally, we'll attempt to query for each hash. We should expect not
// to find a hint for any of them.
for _, txHash := range txHashes {
_, err := hintCache.QueryConfirmHint(txHash)
if err != ErrConfirmHintNotFound {
t.Fatalf("expected ErrConfirmHintNotFound, got :%v", err)
}
}
}
// TestHeightHintCacheSpends ensures that the height hint cache properly caches
// spend hints for outpoints.
func TestHeightHintCacheSpends(t *testing.T) {
t.Parallel()
hintCache := initHintCache(t)
// Querying for an outpoint not found within the cache should return an
// error indication so.
var unknownOutPoint wire.OutPoint
_, err := hintCache.QuerySpendHint(unknownOutPoint)
if err != ErrSpendHintNotFound {
t.Fatalf("expected ErrSpendHintNotFound, got: %v", err)
}
// Now, we'll create some outpoints and commit them to the cache with
// the same spend hint.
const height = 100
const numOutpoints = 5
var txHash chainhash.Hash
copy(txHash[:], bytes.Repeat([]byte{0xFF}, 32))
outpoints := make([]wire.OutPoint, numOutpoints)
for i := uint32(0); i < numOutpoints; i++ {
outpoints[i] = wire.OutPoint{Hash: txHash, Index: i}
}
if err := hintCache.CommitSpendHint(height, outpoints...); err != nil {
t.Fatalf("unable to add entry to cache: %v", err)
}
// With the outpoints committed, we'll now query the cache to ensure
// that we're able to properly retrieve the confirm hints.
for _, op := range outpoints {
spendHint, err := hintCache.QuerySpendHint(op)
if err != nil {
t.Fatalf("unable to query for hint: %v", err)
}
if spendHint != height {
t.Fatalf("expected spend hint %d, got %d", height,
spendHint)
}
}
// We'll also attempt to purge all of them in a single database
// transaction.
if err := hintCache.PurgeSpendHint(outpoints...); err != nil {
t.Fatalf("unable to remove spend hint: %v", err)
}
// Finally, we'll attempt to query for each outpoint. We should expect
// not to find a hint for any of them.
for _, op := range outpoints {
_, err = hintCache.QuerySpendHint(op)
if err != ErrSpendHintNotFound {
t.Fatalf("expected ErrSpendHintNotFound, got: %v", err)
}
}
}