// updateForBatch updates the first argument (the header of a request contained
// in a batch) from the second one (the batch header), returning an error when
// inconsistencies are found.
// It is checked that the individual call does not have a User, UserPriority
// or Txn set that differs from the batch's.
func updateForBatch(args proto.Request, bHeader proto.RequestHeader) error {
// Disallow transaction, user and priority on individual calls, unless
// equal.
aHeader := args.Header()
if aHeader.User != "" && aHeader.User != bHeader.User {
return util.Error("conflicting user on call in batch")
}
if aPrio := aHeader.GetUserPriority(); aPrio != proto.Default_RequestHeader_UserPriority && aPrio != bHeader.GetUserPriority() {
return util.Error("conflicting user priority on call in batch")
}
aHeader.User = bHeader.User
aHeader.UserPriority = bHeader.UserPriority
// Only allow individual transactions on the requests of a batch if
// - the batch is non-transactional,
// - the individual transaction does not write intents, and
// - the individual transaction is initialized.
// The main usage of this is to allow mass-resolution of intents, which
// entails sending a non-txn batch of transactional InternalResolveIntent.
if aHeader.Txn != nil && !aHeader.Txn.Equal(bHeader.Txn) {
if len(aHeader.Txn.ID) == 0 || proto.IsTransactionWrite(args) || bHeader.Txn != nil {
return util.Error("conflicting transaction in transactional batch")
}
} else {
aHeader.Txn = bHeader.Txn
}
return nil
}
// Validate returns an error if any required elements of the Config are missing or invalid.
// Called automatically by NewMultiRaft.
func (c *Config) Validate() error {
if c.Transport == nil {
return util.Error("Transport is required")
}
if c.ElectionTimeoutMin == 0 || c.ElectionTimeoutMax == 0 {
return util.Error("ElectionTimeout{Min,Max} must be non-zero")
}
if c.ElectionTimeoutMin > c.ElectionTimeoutMax {
return util.Error("ElectionTimeoutMin must be <= ElectionTimeoutMax")
}
return nil
}
// addReadOnlyCmd updates the read timestamp cache and waits for any
// overlapping writes currently processing through Raft ahead of us to
// clear via the read queue.
func (r *Range) addReadOnlyCmd(ctx context.Context, args proto.Request, reply proto.Response) error {
header := args.Header()
if err := r.checkCmdHeader(header); err != nil {
reply.Header().SetGoError(err)
return err
}
// If read-consistency is set to INCONSISTENT, run directly.
if header.ReadConsistency == proto.INCONSISTENT {
// But disallow any inconsistent reads within txns.
if header.Txn != nil {
reply.Header().SetGoError(util.Error("cannot allow inconsistent reads within a transaction"))
return reply.Header().GoError()
}
if header.Timestamp.Equal(proto.ZeroTimestamp) {
header.Timestamp = r.rm.Clock().Now()
}
intents, err := r.executeCmd(r.rm.Engine(), nil, args, reply)
if err == nil {
r.handleSkippedIntents(args, intents)
}
return err
} else if header.ReadConsistency == proto.CONSENSUS {
reply.Header().SetGoError(util.Error("consensus reads not implemented"))
return reply.Header().GoError()
}
// Add the read to the command queue to gate subsequent
// overlapping commands until this command completes.
cmdKey := r.beginCmd(header, true)
// This replica must have leader lease to process a consistent read.
if err := r.redirectOnOrAcquireLeaderLease(tracer.FromCtx(ctx), header.Timestamp); err != nil {
r.endCmd(cmdKey, args, err, true /* readOnly */)
reply.Header().SetGoError(err)
return err
}
// Execute read-only command.
intents, err := r.executeCmd(r.rm.Engine(), nil, args, reply)
// Only update the timestamp cache if the command succeeded.
r.endCmd(cmdKey, args, err, true /* readOnly */)
if err == nil {
r.handleSkippedIntents(args, intents)
}
return err
}
// validate returns an error if any required elements of the Config are missing or invalid.
// Called automatically by NewMultiRaft.
func (c *Config) validate() error {
if c.Transport == nil {
return util.Error("Transport is required")
}
if c.ElectionTimeoutTicks == 0 {
return util.Error("ElectionTimeoutTicks must be non-zero")
}
if c.HeartbeatIntervalTicks == 0 {
return util.Error("HeartbeatIntervalTicks must be non-zero")
}
if c.TickInterval == 0 {
return util.Error("TickInterval must be non-zero")
}
return nil
}
// initStores initializes the Stores map from id to Store. Stores are
// added to the local sender if already bootstrapped. A bootstrapped
// Store has a valid ident with cluster, node and Store IDs set. If
// the Store doesn't yet have a valid ident, it's added to the
// bootstraps list for initialization once the cluster and node IDs
// have been determined.
func (n *Node) initStores(clock *hlc.Clock, engines []engine.Engine) error {
bootstraps := list.New()
if len(engines) == 0 {
return util.Error("no engines")
}
for _, e := range engines {
// TODO(bdarnell): use a real transport here instead of NewLocalRPCTransport.
// TODO(bdarnell): arrange to have the transport closed.
s := storage.NewStore(clock, e, n.db, n.gossip, multiraft.NewLocalRPCTransport())
// Initialize each store in turn, handling un-bootstrapped errors by
// adding the store to the bootstraps list.
if err := s.Start(); err != nil {
if _, ok := err.(*storage.NotBootstrappedError); ok {
bootstraps.PushBack(s)
continue
}
return err
}
if s.Ident.ClusterID != "" {
if s.Ident.StoreID == 0 {
return util.Error("cluster id set for node ident but missing store id")
}
capacity, err := s.Capacity()
if err != nil {
return err
}
log.Infof("initialized store %s: %+v", s, capacity)
n.lSender.AddStore(s)
}
}
// Verify all initialized stores agree on cluster and node IDs.
if err := n.validateStores(); err != nil {
return err
}
// Connect gossip before starting bootstrap. For new nodes, connecting
// to the gossip network is necessary to get the cluster ID.
n.connectGossip()
// Bootstrap any uninitialized stores asynchronously.
if bootstraps.Len() > 0 {
go n.bootstrapStores(bootstraps)
}
return nil
}
// CreateRange allocates a new range ID and stores range metadata.
// On success, returns the new range.
func (s *Store) CreateRange(startKey, endKey engine.Key, replicas []proto.Replica) (*Range, error) {
rangeID, err := engine.Increment(s.engine, engine.KeyLocalRangeIDGenerator, 1)
if err != nil {
return nil, err
}
if ok, _ := engine.GetProto(s.engine, makeRangeKey(rangeID), nil); ok {
return nil, util.Error("newly allocated range ID already in use")
}
// RangeMetadata is stored local to this store only. It is neither
// replicated via raft nor available via the global kv store.
meta := &proto.RangeMetadata{
ClusterID: s.Ident.ClusterID,
RangeID: rangeID,
RangeDescriptor: proto.RangeDescriptor{
StartKey: startKey,
EndKey: endKey,
Replicas: replicas,
},
}
err = engine.PutProto(s.engine, makeRangeKey(rangeID), meta)
if err != nil {
return nil, err
}
rng := NewRange(meta, s.clock, s.engine, s.allocator, s.gossip, s)
rng.Start()
s.mu.Lock()
defer s.mu.Unlock()
s.ranges[rangeID] = rng
return rng, nil
}
// newServerTLSConfig creates a server TLSConfig from the supplied byte strings containing
// - the certificate of this node (should be signed by the CA),
// - the private key of this node.
// - the certificate of the cluster CA,
func newServerTLSConfig(certPEM, keyPEM, caPEM []byte) (*tls.Config, error) {
cert, err := tls.X509KeyPair(certPEM, keyPEM)
if err != nil {
return nil, err
}
certPool := x509.NewCertPool()
if ok := certPool.AppendCertsFromPEM(caPEM); !ok {
err = util.Error("failed to parse PEM data to pool")
return nil, err
}
return &tls.Config{
Certificates: []tls.Certificate{cert},
// Verify client certs if passed.
ClientAuth: tls.VerifyClientCertIfGiven,
RootCAs: certPool,
ClientCAs: certPool,
// Use the default cipher suite from golang (RC4 is going away in 1.5).
// Prefer the server-specified suite.
PreferServerCipherSuites: true,
// TLS 1.1 and 1.2 support is crappy out there. Let's use 1.0.
MinVersion: tls.VersionTLS10,
// Should we disable session resumption? This may break forward secrecy.
// SessionTicketsDisabled: true,
}, nil
}
// CreateRange allocates a new range ID and stores range metadata.
// On success, returns the new range.
func (s *Store) CreateRange(startKey, endKey Key, replicas []Replica) (*Range, error) {
rangeID, err := increment(s.engine, storeKeyRangeIDGenerator, 1, time.Now().UnixNano())
if err != nil {
return nil, err
}
if ok, _, _ := getI(s.engine, rangeKey(rangeID), nil); ok {
return nil, util.Error("newly allocated range ID already in use")
}
// RangeMetadata is stored local to this store only. It is neither
// replicated via raft nor available via the global kv store.
meta := RangeMetadata{
ClusterID: s.Ident.ClusterID,
RangeID: rangeID,
StartKey: startKey,
EndKey: endKey,
Desc: RangeDescriptor{
StartKey: startKey,
Replicas: replicas,
},
}
err = putI(s.engine, rangeKey(rangeID), meta)
if err != nil {
return nil, err
}
rng := NewRange(meta, s.engine, s.allocator, s.gossip)
rng.Start()
s.mu.Lock()
defer s.mu.Unlock()
s.ranges[rangeID] = rng
return rng, nil
}
// ParseTimestamp parses the timestamp.
func ParseTimestamp(s DString) (DTimestamp, error) {
str := string(s)
t, err := time.Parse(timestampFormat, str)
if err == nil {
t = t.UTC()
return DTimestamp{Time: t}, nil
}
t, err = time.Parse(timestampWithOffsetZoneFormat, str)
if err == nil {
t = t.UTC()
return DTimestamp{Time: t}, nil
}
t, err = time.Parse(timestampWithNamedZoneFormat, str)
if err == nil {
// Parsing using a named time zone is imperfect for two reasons:
// 1. Some named time zones are ambiguous (PST can be US PST and
// phillipines PST), and 2. The code needs to have access to the entire
// database of named timed zones in order to get some time offset,
// and it's not clear what are the memory requirements for that.
// TODO(vivek): Implement SET TIME ZONE to set a time zone and use
// time.ParseInLocation()
return DummyTimestamp, util.Error("TODO(vivek): named time zone input not supported")
}
// Parse other formats in the future.
return DummyTimestamp, err
}
// Merge appends the input value to the string and returns the result.
func (s Appender) Merge(t Mergable) (Mergable, error) {
m, ok := t.(Appender)
if !ok {
return s, util.Error("parameter is of wrong type")
}
return append(s, m...), nil
}
// NewMultiRaft creates a MultiRaft object.
func NewMultiRaft(nodeID NodeID, config *Config) (*MultiRaft, error) {
if !nodeID.isSet() {
return nil, util.Error("Invalid NodeID")
}
err := config.Validate()
if err != nil {
return nil, err
}
if config.Clock == nil {
config.Clock = RealClock
}
m := &MultiRaft{
Config: *config,
nodeID: nodeID,
Events: make(chan interface{}, 1000),
ops: make(chan interface{}, 100),
requests: make(chan *rpc.Call, 100),
stopped: make(chan struct{}),
}
err = m.Transport.Listen(nodeID, m)
if err != nil {
return nil, err
}
return m, nil
}
// replaceNode cuts a node away form its parent, substituting a new node or
// nil. The updated new node is returned. Note that this does not in fact alter
// the old node in any way, but only the old node's parent and the new node.
func (tc *treeContext) replaceNode(oldNode, newNode *proto.RangeTreeNode) (*proto.RangeTreeNode, error) {
if oldNode.ParentKey == nil {
if newNode == nil {
return nil, util.Error("cannot replace the root node with nil")
}
// Update the root key if this was the root.
tc.setRootKey(newNode.Key)
} else {
oldParent, err := tc.getNode(oldNode.ParentKey)
if err != nil {
return nil, err
}
if oldParent.LeftKey != nil && oldNode.Key.Equal(oldParent.LeftKey) {
if newNode == nil {
oldParent.LeftKey = nil
} else {
oldParent.LeftKey = newNode.Key
}
} else {
if newNode == nil {
oldParent.RightKey = nil
} else {
oldParent.RightKey = newNode.Key
}
}
tc.setNode(oldParent)
}
if newNode != nil {
newNode.ParentKey = oldNode.ParentKey
tc.setNode(newNode)
}
return newNode, nil
}
// sendBatch unrolls a batched command and sends each constituent
// command in parallel.
func (tc *TxnCoordSender) sendBatch(batchArgs *proto.InternalBatchRequest, batchReply *proto.InternalBatchResponse) {
// Prepare the calls by unrolling the batch. If the batchReply is
// pre-initialized with replies, use those; otherwise create replies
// as needed.
// TODO(spencer): send calls in parallel.
batchReply.Txn = batchArgs.Txn
for i := range batchArgs.Requests {
args := batchArgs.Requests[i].GetValue().(proto.Request)
call := proto.Call{Args: args}
// Disallow transaction, user and priority on individual calls, unless
// equal.
if args.Header().User != "" && args.Header().User != batchArgs.User {
batchReply.Header().SetGoError(util.Error("cannot have individual user on call in batch"))
return
}
args.Header().User = batchArgs.User
if args.Header().UserPriority != nil && args.Header().GetUserPriority() != batchArgs.GetUserPriority() {
batchReply.Header().SetGoError(util.Error("cannot have individual user priority on call in batch"))
return
}
args.Header().UserPriority = batchArgs.UserPriority
if txn := args.Header().Txn; txn != nil && !txn.Equal(batchArgs.Txn) {
batchReply.Header().SetGoError(util.Error("cannot have individual transactional call in batch"))
return
}
// Propagate batch Txn to each call.
args.Header().Txn = batchArgs.Txn
// Create a reply from the method type and add to batch response.
if i >= len(batchReply.Responses) {
call.Reply = args.CreateReply()
batchReply.Add(call.Reply)
} else {
call.Reply = batchReply.Responses[i].GetValue().(proto.Response)
}
tc.sendOne(call)
// Amalgamate transaction updates and propagate first error, if applicable.
if batchReply.Txn != nil {
batchReply.Txn.Update(call.Reply.Header().Txn)
}
if call.Reply.Header().Error != nil {
batchReply.Error = call.Reply.Header().Error
return
}
}
}
// ResolveWriteIntentRange commits or aborts (rolls back)
// the range of write intents specified by start and end
// keys for a given txnID according to commit parameter.
// ResolveWriteIntentRange will skip write intents of
// other txnIDs. Specify max=0 for unbounded resolves.
func (mvcc *MVCC) ResolveWriteIntentRange(key Key, endKey Key, max int64, txnID string, commit bool) (int64, error) {
if len(txnID) == 0 {
return 0, util.Error("missing txnID in request")
}
nextKey := key
// TODO(Jiang-Ming): remove this after we put everything via MVCC.
// Currently, we need to skip the series of reserved system
// key / value pairs covering accounting, range metadata, node
// accounting and permissions before the actual key / value pairs
// since they don't have keyMetadata.
if nextKey.Less(PrefixEndKey(Key("\x00"))) {
nextKey = PrefixEndKey(Key("\x00"))
}
num := int64(0)
for {
kvs, err := mvcc.engine.Scan(nextKey, endKey, 1)
if err != nil {
return num, err
}
// No more keys exists in the given range.
if len(kvs) == 0 {
break
}
currentKey := kvs[0].Key
_, existingTxnID, err := mvcc.Get(currentKey, hlc.MaxHLTimestamp, txnID)
// Return the error unless its a writeIntentError, which
// will occur in the event we scan a key with a write
// intent belonging to a different transaction.
if _, ok := err.(*writeIntentError); err != nil && !ok {
return num, err
}
// endRangTransaction only needs to deal with the write
// intents for the given txnID.
if err == nil && existingTxnID == txnID {
// commits or aborts (rolls back) the write intent of
// the given txnID.
err = mvcc.ResolveWriteIntent(currentKey, txnID, commit)
if err != nil {
return num, err
}
num++
}
if max != 0 && max == num {
break
}
// In order to efficiently skip the possibly long list of
// old versions for this key, please refer to scan function
// for details.
nextKey = NextKey(mvccEncodeKey(currentKey, hlc.MinHLTimestamp))
}
return num, nil
}
// updateForBatch updates the first argument (the header of a request contained
// in a batch) from the second one (the batch header), returning an error when
// inconsistencies are found.
// It is checked that the individual call does not have a User, UserPriority
// or Txn set that differs from the batch's.
func updateForBatch(aHeader *proto.RequestHeader, bHeader proto.RequestHeader) error {
// Disallow transaction, user and priority on individual calls, unless
// equal.
if aHeader.User != "" && aHeader.User != bHeader.User {
return util.Error("conflicting user on call in batch")
}
if aPrio := aHeader.GetUserPriority(); aPrio != proto.Default_RequestHeader_UserPriority && aPrio != bHeader.GetUserPriority() {
return util.Error("conflicting user priority on call in batch")
}
if aHeader.Txn != nil && !aHeader.Txn.Equal(bHeader.Txn) {
return util.Error("conflicting transaction in transactional batch")
}
aHeader.User = bHeader.User
aHeader.UserPriority = bHeader.UserPriority
aHeader.Txn = bHeader.Txn
return nil
}
// getDescriptors takes a call and looks up the corresponding range
// descriptors associated with it. First, the range descriptor for
// call.Args.Key is looked up. If call.Args.EndKey exceeds that of the
// returned descriptor, the next descriptor is obtained as well.
func (ds *DistSender) getDescriptors(call proto.Call) (*proto.RangeDescriptor, *proto.RangeDescriptor, error) {
// If this is a PushTxn, set ignoreIntents option as
// necessary. This prevents a potential infinite loop; see the
// comments in proto.RangeLookupRequest.
options := lookupOptions{}
if pushArgs, ok := call.Args.(*proto.PushTxnRequest); ok {
options.ignoreIntents = pushArgs.RangeLookup
}
var desc *proto.RangeDescriptor
var err error
_, isReverseScan := call.Args.(*proto.ReverseScanRequest)
if !isReverseScan {
desc, err = ds.rangeCache.LookupRangeDescriptor(call.Args.Header().Key, options)
} else {
options.useReverseScan = true
desc, err = ds.rangeCache.LookupRangeDescriptor(call.Args.Header().EndKey, options)
}
if err != nil {
return nil, nil, err
}
// Checks whether need to get next range descriptor. If so, returns true
// and the key to look up, depending on whether we're in reverse mode.
needAnother := func(desc *proto.RangeDescriptor, isReverseScan bool) (proto.Key, bool) {
if isReverseScan {
return desc.StartKey, call.Args.Header().Key.Less(desc.StartKey)
}
return desc.EndKey, desc.EndKey.Less(call.Args.Header().EndKey)
}
var descNext *proto.RangeDescriptor
// If the request accesses keys beyond the end of this range,
// get the descriptor of the adjacent range to address next.
if nextKey, ok := needAnother(desc, isReverseScan); ok {
if _, ok := call.Reply.(proto.Combinable); !ok {
return nil, nil, util.Error("illegal cross-range operation")
}
// If there's no transaction and op spans ranges, possibly
// re-run as part of a transaction for consistency. The
// case where we don't need to re-run is if the read
// consistency is not required.
if call.Args.Header().Txn == nil &&
call.Args.Header().ReadConsistency != proto.INCONSISTENT {
return nil, nil, &proto.OpRequiresTxnError{}
}
// This next lookup is likely for free since we've read the
// previous descriptor and range lookups use cache
// prefetching.
descNext, err = ds.rangeCache.LookupRangeDescriptor(nextKey, options)
if err != nil {
return nil, nil, err
}
}
return desc, descNext, nil
}
// CreateGroup creates a new consensus group and joins it. The application should
// arrange to call CreateGroup on all nodes named in initialMembers.
func (m *MultiRaft) CreateGroup(groupID GroupID, initialMembers []NodeID) error {
for _, id := range initialMembers {
if !id.isSet() {
return util.Error("Invalid NodeID")
}
}
op := &createGroupOp{newGroup(groupID, initialMembers), make(chan error)}
m.ops <- op
return <-op.ch
}
// initStores initializes the Stores map from id to Store. Stores are
// added to the local sender if already bootstrapped. A bootstrapped
// Store has a valid ident with cluster, node and Store IDs set. If
// the Store doesn't yet have a valid ident, it's added to the
// bootstraps list for initialization once the cluster and node IDs
// have been determined.
func (n *Node) initStores(engines []engine.Engine, stopper *util.Stopper) error {
bootstraps := list.New()
if len(engines) == 0 {
return util.Error("no engines")
}
for _, e := range engines {
s := storage.NewStore(n.ctx, e, &n.Descriptor)
// Initialize each store in turn, handling un-bootstrapped errors by
// adding the store to the bootstraps list.
if err := s.Start(stopper); err != nil {
if _, ok := err.(*storage.NotBootstrappedError); ok {
log.Infof("store %s not bootstrapped", s)
bootstraps.PushBack(s)
continue
}
return util.Errorf("failed to start store: %s", err)
}
if s.Ident.ClusterID == "" || s.Ident.NodeID == 0 {
return util.Errorf("unidentified store: %s", s)
}
capacity, err := s.Capacity()
if err != nil {
return util.Errorf("could not query store capacity: %s", err)
}
log.Infof("initialized store %s: %+v", s, capacity)
n.lSender.AddStore(s)
}
// Verify all initialized stores agree on cluster and node IDs.
if err := n.validateStores(); err != nil {
return err
}
// Connect gossip before starting bootstrap. For new nodes, connecting
// to the gossip network is necessary to get the cluster ID.
n.connectGossip()
// If no NodeID has been assigned yet, allocate a new node ID by
// supplying 0 to initNodeID.
if n.Descriptor.NodeID == 0 {
n.initNodeID(0)
}
// Bootstrap any uninitialized stores asynchronously.
if bootstraps.Len() > 0 && stopper.StartTask() {
go func() {
n.bootstrapStores(bootstraps, stopper)
stopper.FinishTask()
}()
}
return nil
}
// Merge updates the value of this Counter with the supplied
// update and returns an error in case of an integer overflow.
func (n Counter) Merge(o Mergable) (Mergable, error) {
m, ok := o.(Counter)
if !ok {
return n, util.Error("parameter is of wrong type")
}
if encoding.WillOverflow(int64(n), int64(m)) {
return n, util.Errorf("merge error: %d + %d overflows", n, m)
}
result := Counter(n + m)
return result, nil
}
// ResolveWriteIntentRange commits or aborts (rolls back) the range of
// write intents specified by start and end keys for a given txnID
// according to commit parameter. ResolveWriteIntentRange will skip
// write intents of other txnIDs. Specify max=0 for unbounded
// resolves.
func (mvcc *MVCC) ResolveWriteIntentRange(key Key, endKey Key, max int64, txnID []byte, commit bool) (int64, error) {
if len(txnID) == 0 {
return 0, util.Error("missing txnID in request")
}
binKey := encoding.EncodeBinary(nil, key)
binEndKey := encoding.EncodeBinary(nil, endKey)
nextKey := binKey
num := int64(0)
for {
kvs, err := mvcc.engine.Scan(nextKey, binEndKey, 1)
if err != nil {
return num, err
}
// No more keys exists in the given range.
if len(kvs) == 0 {
break
}
remainder, currentKey := encoding.DecodeBinary(kvs[0].Key)
if len(remainder) != 0 {
return 0, util.Errorf("expected an MVCC metadata key: %s", kvs[0].Key)
}
_, _, existingTxnID, err := mvcc.getInternal(kvs[0].Key, proto.MaxTimestamp, txnID)
// Return the error unless its a writeIntentError, which
// will occur in the event we scan a key with a write
// intent belonging to a different transaction.
if _, ok := err.(*writeIntentError); err != nil && !ok {
return num, err
}
// ResolveWriteIntent only needs to deal with the write
// intents for the given txnID.
if err == nil && bytes.Equal(existingTxnID, txnID) {
// commits or aborts (rolls back) the write intent of
// the given txnID.
err = mvcc.ResolveWriteIntent(currentKey, txnID, commit)
if err != nil {
return num, err
}
num++
}
if max != 0 && max == num {
break
}
// In order to efficiently skip the possibly long list of
// old versions for this key; refer to Scan for details.
nextKey = encoding.EncodeBinary(nil, NextKey(currentKey))
}
return num, nil
}
// goMerge takes existing and update byte slices. It first attempts
// to gob-unmarshal the update string, returning an error on failure.
// The unmarshaled value must satisfy the Mergable interface.
// Next, it unmarshals the existing string, falling back to the init
// value supplied by the update value's Init() method if necessary.
// The two values obtained in this way are merged and the result, or
// an error, returned.
func goMerge(existing, update []byte) ([]byte, error) {
u, err := encoding.GobDecode(update)
if err != nil {
return nil, util.Errorf("merge: %v", err)
}
if _, ok := u.(Mergable); !ok {
return nil, util.Error("update is not Mergable")
}
e, err := encoding.GobDecode(existing)
if err != nil {
e = u.(Mergable).Init(existing)
}
if reflect.TypeOf(u) != reflect.TypeOf(e) {
return nil, util.Error("cannot merge values of different type")
}
newValue, err := e.(Mergable).Merge(u.(Mergable))
if err != nil {
return nil, err
}
return encoding.GobEncode(newValue)
}
// ResolveWriteIntent either commits or aborts (rolls back) an extant
// write intent for a given txnID according to commit parameter.
// ResolveWriteIntent will skip write intents of other txnIDs.
func (mvcc *MVCC) ResolveWriteIntent(key Key, txnID []byte, commit bool) error {
if len(txnID) == 0 {
return util.Error("missing txnID in request")
}
binKey := encoding.EncodeBinary(nil, key)
meta := &proto.MVCCMetadata{}
ok, err := GetProto(mvcc.engine, binKey, meta)
if err != nil {
return err
}
if !ok {
return util.Errorf("key %q does not exist", key)
}
if len(meta.TxnID) == 0 {
return util.Errorf("write intent %q does not exist", key)
}
if !bytes.Equal(meta.TxnID, txnID) {
return util.Errorf("cannot commit another TxnID %s from TxnID %s",
meta.TxnID, txnID)
}
if !commit {
latestKey := mvccEncodeKey(binKey, meta.Timestamp)
err = mvcc.engine.Clear(latestKey)
if err != nil {
return err
}
// Compute the next possible mvcc value for this key.
nextKey := NextKey(latestKey)
// Compute the last possible mvcc value for this key.
endScanKey := encoding.EncodeBinary(nil, NextKey(key))
kvs, err := mvcc.engine.Scan(nextKey, endScanKey, 1)
if err != nil {
return err
}
// If there is no other version, we should just clean up the key entirely.
if len(kvs) == 0 {
return mvcc.engine.Clear(binKey)
}
_, ts, isValue := mvccDecodeKey(kvs[0].Key)
if !isValue {
return util.Errorf("expected an MVCC value key: %s", kvs[0].Key)
}
// Update the keyMetadata with the next version.
return PutProto(mvcc.engine, binKey, &proto.MVCCMetadata{TxnID: nil, Timestamp: ts})
}
return PutProto(mvcc.engine, binKey, &proto.MVCCMetadata{TxnID: nil, Timestamp: meta.Timestamp})
}
// NewMultiRaft creates a MultiRaft object.
func NewMultiRaft(nodeID proto.RaftNodeID, config *Config, stopper *util.Stopper) (*MultiRaft, error) {
if nodeID == 0 {
return nil, util.Error("Invalid RaftNodeID")
}
if err := config.validate(); err != nil {
return nil, err
}
if config.Ticker == nil {
config.Ticker = newTicker(config.TickInterval)
stopper.AddCloser(config.Ticker)
}
if config.EntryFormatter != nil {
// Wrap the EntryFormatter to strip off the command id.
ef := config.EntryFormatter
config.EntryFormatter = func(data []byte) string {
if len(data) == 0 {
return "[empty]"
}
id, cmd := decodeCommand(data)
formatted := ef(cmd)
return fmt.Sprintf("%x: %s", id, formatted)
}
}
m := &MultiRaft{
Config: *config,
stopper: stopper,
multiNode: raft.StartMultiNode(uint64(nodeID)),
nodeID: nodeID,
// Output channel.
Events: make(chan interface{}, config.EventBufferSize),
// Input channels.
reqChan: make(chan *RaftMessageRequest),
createGroupChan: make(chan *createGroupOp),
removeGroupChan: make(chan *removeGroupOp),
proposalChan: make(chan *proposal),
callbackChan: make(chan func()),
}
if err := m.Transport.Listen(nodeID, (*multiraftServer)(m)); err != nil {
return nil, err
}
return m, nil
}
// rotateLeft performs a left rotation around the node.
func (tc *treeContext) rotateLeft(node *proto.RangeTreeNode) (*proto.RangeTreeNode, error) {
right, err := tc.getNode(node.RightKey)
if err != nil {
return nil, err
}
if right.Black {
return nil, util.Error("rotating a black node")
}
node.RightKey = right.LeftKey
right.LeftKey = &node.Key
right.Black = node.Black
node.Black = false
tc.setNode(node)
tc.setNode(right)
return right, nil
}
// rotateRight performs a right rotation around the node.
func (tc *treeContext) rotateRight(node *proto.RangeTreeNode) (*proto.RangeTreeNode, error) {
left, err := tc.getNode(node.LeftKey)
if err != nil {
return nil, err
}
if left.Black {
return nil, util.Error("rotating a black node")
}
node.LeftKey = left.RightKey
left.RightKey = &node.Key
left.Black = node.Black
node.Black = false
tc.setNode(node)
tc.setNode(left)
return left, nil
}
// NewMultiRaft creates a MultiRaft object.
func NewMultiRaft(nodeID NodeID, config *Config) (*MultiRaft, error) {
if nodeID == 0 {
return nil, util.Error("Invalid NodeID")
}
err := config.validate()
if err != nil {
return nil, err
}
if config.Ticker == nil {
config.Ticker = newTicker(config.TickInterval)
}
if config.EntryFormatter != nil {
// Wrap the EntryFormatter to strip off the command id.
ef := config.EntryFormatter
config.EntryFormatter = func(data []byte) string {
if len(data) == 0 {
return "[empty]"
}
id, cmd := decodeCommand(data)
formatted := ef(cmd)
return fmt.Sprintf("%x: %s", id, formatted)
}
}
m := &MultiRaft{
Config: *config,
multiNode: raft.StartMultiNode(uint64(nodeID), config.ElectionTimeoutTicks,
config.HeartbeatIntervalTicks),
nodeID: nodeID,
Events: make(chan interface{}, 1000),
reqChan: make(chan *RaftMessageRequest, 100),
createGroupChan: make(chan *createGroupOp, 100),
removeGroupChan: make(chan *removeGroupOp, 100),
proposalChan: make(chan *proposal, 100),
callbackChan: make(chan func(), 100),
stopper: util.NewStopper(1),
}
err = m.Transport.Listen(nodeID, (*multiraftServer)(m))
if err != nil {
return nil, err
}
return m, nil
}
// RemoveTarget returns a suitable replica to remove from the provided replica
// set. It attempts to consider which of the provided replicas would be the best
// candidate for removal.
//
// TODO(mrtracy): RemoveTarget eventually needs to accept the attributes from
// the zone config associated with the provided replicas. This will allow it to
// make correct decisions in the case of ranges with heterogeneous replica
// requirements (i.e. multiple data centers).
func (a *allocator) RemoveTarget(existing []proto.Replica) (proto.Replica, error) {
if len(existing) == 0 {
return proto.Replica{}, util.Error("must supply at least one replica to allocator.RemoveTarget()")
}
a.Lock()
defer a.Unlock()
// Retrieve store descriptors for the provided replicas from gossip.
type replStore struct {
repl proto.Replica
store *proto.StoreDescriptor
}
replStores := make([]replStore, len(existing))
usedStat := stat{}
for i := range existing {
desc, err := storeDescFromGossip(gossip.MakeStoreKey(existing[i].StoreID), a.gossip)
if err != nil {
return proto.Replica{}, err
}
replStores[i] = replStore{
repl: existing[i],
store: desc,
}
usedStat.Update(desc.Capacity.FractionUsed())
}
// Based on store statistics, determine which replica is the "worst" and
// thus should be removed.
var worst replStore
for i, rs := range replStores {
if i == 0 {
worst = rs
continue
}
if usedStat.mean < minFractionUsedThreshold {
if rs.store.Capacity.RangeCount > worst.store.Capacity.RangeCount {
worst = rs
}
continue
}
if rs.store.Capacity.FractionUsed() > worst.store.Capacity.FractionUsed() {
worst = rs
}
}
return worst.repl, nil
}
// addAdminCmd executes the command directly. There is no interaction
// with the command queue or the timestamp cache, as admin commands
// are not meant to consistently access or modify the underlying data.
// Admin commands must run on the leader replica.
func (r *Range) addAdminCmd(ctx context.Context, args proto.Request, reply proto.Response) error {
// Admin commands always require the leader lease.
if err := r.redirectOnOrAcquireLeaderLease(args.Header().Timestamp); err != nil {
reply.Header().SetGoError(err)
return err
}
switch args.(type) {
case *proto.AdminSplitRequest:
r.AdminSplit(args.(*proto.AdminSplitRequest), reply.(*proto.AdminSplitResponse))
case *proto.AdminMergeRequest:
r.AdminMerge(args.(*proto.AdminMergeRequest), reply.(*proto.AdminMergeResponse))
default:
return util.Error("unrecognized admin command")
}
return reply.Header().GoError()
}
func (s *state) addLogEntry(groupID GroupID, entryType LogEntryType, payload []byte) error {
g := s.groups[groupID]
if g.role != RoleLeader {
return util.Error("TODO(bdarnell): forward commands to leader")
}
g.lastLogIndex++
entry := &LogEntry{
Term: g.electionState.CurrentTerm,
Index: g.lastLogIndex,
Type: entryType,
Payload: payload,
}
g.pendingEntries = append(g.pendingEntries, entry)
s.updateDirtyStatus(g)
return nil
}
// ResolveWriteIntent either commits or aborts (rolls back) an extant
// write intent for a given txnID according to commit parameter.
// ResolveWriteIntent will skip write intents of other txnIDs.
func (mvcc *MVCC) ResolveWriteIntent(key Key, txnID string, commit bool) error {
if len(txnID) == 0 {
return util.Error("missing txnID in request")
}
keyMeta := &keyMetadata{}
ok, err := GetI(mvcc.engine, key, keyMeta)
if err != nil {
return err
}
if !ok {
return util.Errorf("key %q does not exist", key)
}
if len(keyMeta.TxnID) == 0 {
return util.Errorf("write intent does not exist", key)
}
if keyMeta.TxnID != txnID {
return util.Errorf("cannot commit another TxnID %s from TxnID %s",
keyMeta.TxnID, txnID)
}
if !commit {
latestKey := mvccEncodeKey(key, keyMeta.Timestamp)
err = mvcc.engine.Clear(latestKey)
if err != nil {
return err
}
nextKey := NextKey(latestKey)
kvs, err := mvcc.engine.Scan(nextKey, PrefixEndKey(key), 1)
if err != nil {
return err
}
// If there is no other version, we should just clean up the key entirely.
if len(kvs) == 0 {
return mvcc.engine.Clear(key)
}
_, ts := mvccDecodeKey(kvs[0].Key)
// Update the keyMetadata with the next version.
return PutI(mvcc.engine, key, &keyMetadata{TxnID: "", Timestamp: ts})
}
return PutI(mvcc.engine, key, &keyMetadata{TxnID: "", Timestamp: keyMeta.Timestamp})
}
