lotus/chain/blocksync/client.go
Steven Allen 5733c71c50 Lint everything
We were ignoring quite a few error cases, and had one case where we weren't
actually updating state where we wanted to. Unfortunately, if the linter doesn't
pass, nobody has any reason to actually check lint failures in CI.

There are three remaining XXXs marked in the code for lint.
2020-08-20 20:46:36 -07:00

447 lines
13 KiB
Go

package blocksync
import (
"bufio"
"context"
"fmt"
"math/rand"
"time"
host "github.com/libp2p/go-libp2p-core/host"
inet "github.com/libp2p/go-libp2p-core/network"
"github.com/libp2p/go-libp2p-core/peer"
"go.opencensus.io/trace"
"golang.org/x/xerrors"
cborutil "github.com/filecoin-project/go-cbor-util"
"github.com/filecoin-project/lotus/build"
"github.com/filecoin-project/lotus/chain/store"
"github.com/filecoin-project/lotus/chain/types"
incrt "github.com/filecoin-project/lotus/lib/increadtimeout"
"github.com/filecoin-project/lotus/lib/peermgr"
)
// Protocol client.
// FIXME: Rename to just `Client`. Not done at the moment to avoid
// disrupting too much of the consumer code, should be done along
// https://github.com/filecoin-project/lotus/issues/2612.
type BlockSync struct {
// Connection manager used to contact the server.
// FIXME: We should have a reduced interface here, initialized
// just with our protocol ID, we shouldn't be able to open *any*
// connection.
host host.Host
peerTracker *bsPeerTracker
}
func NewClient(
host host.Host,
pmgr peermgr.MaybePeerMgr,
) *BlockSync {
return &BlockSync{
host: host,
peerTracker: newPeerTracker(pmgr.Mgr),
}
}
// Main logic of the client request service. The provided `Request`
// is sent to the `singlePeer` if one is indicated or to all available
// ones otherwise. The response is processed and validated according
// to the `Request` options. Either a `validatedResponse` is returned
// (which can be safely accessed), or an `error` that may represent
// either a response error status, a failed validation or an internal
// error.
//
// This is the internal single point of entry for all external-facing
// APIs, currently we have 3 very heterogeneous services exposed:
// * GetBlocks: Headers
// * GetFullTipSet: Headers | Messages
// * GetChainMessages: Messages
// This function handles all the different combinations of the available
// request options without disrupting external calls. In the future the
// consumers should be forced to use a more standardized service and
// adhere to a single API derived from this function.
func (client *BlockSync) doRequest(
ctx context.Context,
req *Request,
singlePeer *peer.ID,
) (*validatedResponse, error) {
// Validate request.
if req.Length == 0 {
return nil, xerrors.Errorf("invalid request of length 0")
}
if req.Length > MaxRequestLength {
return nil, xerrors.Errorf("request length (%d) above maximum (%d)",
req.Length, MaxRequestLength)
}
if req.Options == 0 {
return nil, xerrors.Errorf("request with no options set")
}
// Generate the list of peers to be queried, either the
// `singlePeer` indicated or all peers available (sorted
// by an internal peer tracker with some randomness injected).
var peers []peer.ID
if singlePeer != nil {
peers = []peer.ID{*singlePeer}
} else {
peers = client.getShuffledPeers()
if len(peers) == 0 {
return nil, xerrors.Errorf("no peers available")
}
}
// Try the request for each peer in the list,
// return on the first successful response.
// FIXME: Doing this serially isn't great, but fetching in parallel
// may not be a good idea either. Think about this more.
globalTime := build.Clock.Now()
// Global time used to track what is the expected time we will need to get
// a response if a client fails us.
for _, peer := range peers {
select {
case <-ctx.Done():
return nil, xerrors.Errorf("context cancelled: %w", ctx.Err())
default:
}
// Send request, read response.
res, err := client.sendRequestToPeer(ctx, peer, req)
if err != nil {
if !xerrors.Is(err, inet.ErrNoConn) {
log.Warnf("could not connect to peer %s: %s",
peer.String(), err)
}
continue
}
// Process and validate response.
validRes, err := client.processResponse(req, res)
if err != nil {
log.Warnf("processing peer %s response failed: %s",
peer.String(), err)
continue
}
client.peerTracker.logGlobalSuccess(build.Clock.Since(globalTime))
client.host.ConnManager().TagPeer(peer, "bsync", SUCCESS_PEER_TAG_VALUE)
return validRes, nil
}
errString := "doRequest failed for all peers"
if singlePeer != nil {
errString = fmt.Sprintf("doRequest failed for single peer %s", *singlePeer)
}
return nil, xerrors.Errorf(errString)
}
// Process and validate response. Check the status, the integrity of the
// information returned, and that it matches the request. Extract the information
// into a `validatedResponse` for the external-facing APIs to select what they
// need.
//
// We are conflating in the single error returned both status and validation
// errors. Peer penalization should happen here then, before returning, so
// we can apply the correct penalties depending on the cause of the error.
func (client *BlockSync) processResponse(
req *Request,
res *Response,
// FIXME: Add the `peer` as argument once we implement penalties.
) (*validatedResponse, error) {
err := res.statusToError()
if err != nil {
return nil, xerrors.Errorf("status error: %s", err)
}
options := parseOptions(req.Options)
if options.noOptionsSet() {
// Safety check: this shouldn't have been sent, and even if it did
// it should have been caught by the peer in its error status.
return nil, xerrors.Errorf("nothing was requested")
}
// Verify that the chain segment returned is in the valid range.
// Note that the returned length might be less than requested.
resLength := len(res.Chain)
if resLength == 0 {
return nil, xerrors.Errorf("got no chain in successful response")
}
if resLength > int(req.Length) {
return nil, xerrors.Errorf("got longer response (%d) than requested (%d)",
resLength, req.Length)
}
if resLength < int(req.Length) && res.Status != Partial {
return nil, xerrors.Errorf("got less than requested without a proper status: %d", res.Status)
}
validRes := &validatedResponse{}
if options.IncludeHeaders {
// Check for valid block sets and extract them into `TipSet`s.
validRes.tipsets = make([]*types.TipSet, resLength)
for i := 0; i < resLength; i++ {
validRes.tipsets[i], err = types.NewTipSet(res.Chain[i].Blocks)
if err != nil {
return nil, xerrors.Errorf("invalid tipset blocks at height (head - %d): %w", i, err)
}
}
// Check that the returned head matches the one requested.
if !types.CidArrsEqual(validRes.tipsets[0].Cids(), req.Head) {
return nil, xerrors.Errorf("returned chain head does not match request")
}
// Check `TipSet`s are connected (valid chain).
for i := 0; i < len(validRes.tipsets)-1; i++ {
if validRes.tipsets[i].IsChildOf(validRes.tipsets[i+1]) == false {
return nil, fmt.Errorf("tipsets are not connected at height (head - %d)/(head - %d)",
i, i+1)
// FIXME: Maybe give more information here, like CIDs.
}
}
}
if options.IncludeMessages {
validRes.messages = make([]*CompactedMessages, resLength)
for i := 0; i < resLength; i++ {
if res.Chain[i].Messages == nil {
return nil, xerrors.Errorf("no messages included for tipset at height (head - %d)", i)
}
validRes.messages[i] = res.Chain[i].Messages
}
if options.IncludeHeaders {
// If the headers were also returned check that the compression
// indexes are valid before `toFullTipSets()` is called by the
// consumer.
for tipsetIdx := 0; tipsetIdx < resLength; tipsetIdx++ {
msgs := res.Chain[tipsetIdx].Messages
blocksNum := len(res.Chain[tipsetIdx].Blocks)
if len(msgs.BlsIncludes) != blocksNum {
return nil, xerrors.Errorf("BlsIncludes (%d) does not match number of blocks (%d)",
len(msgs.BlsIncludes), blocksNum)
}
if len(msgs.SecpkIncludes) != blocksNum {
return nil, xerrors.Errorf("SecpkIncludes (%d) does not match number of blocks (%d)",
len(msgs.SecpkIncludes), blocksNum)
}
for blockIdx := 0; blockIdx < blocksNum; blockIdx++ {
for _, mi := range msgs.BlsIncludes[blockIdx] {
if int(mi) >= len(msgs.Bls) {
return nil, xerrors.Errorf("index in BlsIncludes (%d) exceeds number of messages (%d)",
mi, len(msgs.Bls))
}
}
for _, mi := range msgs.SecpkIncludes[blockIdx] {
if int(mi) >= len(msgs.Secpk) {
return nil, xerrors.Errorf("index in SecpkIncludes (%d) exceeds number of messages (%d)",
mi, len(msgs.Secpk))
}
}
}
}
}
}
return validRes, nil
}
// GetBlocks fetches count blocks from the network, from the provided tipset
// *backwards*, returning as many tipsets as count.
//
// {hint/usage}: This is used by the Syncer during normal chain syncing and when
// resolving forks.
func (client *BlockSync) GetBlocks(
ctx context.Context,
tsk types.TipSetKey,
count int,
) ([]*types.TipSet, error) {
ctx, span := trace.StartSpan(ctx, "bsync.GetBlocks")
defer span.End()
if span.IsRecordingEvents() {
span.AddAttributes(
trace.StringAttribute("tipset", fmt.Sprint(tsk.Cids())),
trace.Int64Attribute("count", int64(count)),
)
}
req := &Request{
Head: tsk.Cids(),
Length: uint64(count),
Options: Headers,
}
validRes, err := client.doRequest(ctx, req, nil)
if err != nil {
return nil, err
}
return validRes.tipsets, nil
}
func (client *BlockSync) GetFullTipSet(
ctx context.Context,
peer peer.ID,
tsk types.TipSetKey,
) (*store.FullTipSet, error) {
// TODO: round robin through these peers on error
req := &Request{
Head: tsk.Cids(),
Length: 1,
Options: Headers | Messages,
}
validRes, err := client.doRequest(ctx, req, &peer)
if err != nil {
return nil, err
}
return validRes.toFullTipSets()[0], nil
// If `doRequest` didn't fail we are guaranteed to have at least
// *one* tipset here, so it's safe to index directly.
}
func (client *BlockSync) GetChainMessages(
ctx context.Context,
head *types.TipSet,
length uint64,
) ([]*CompactedMessages, error) {
ctx, span := trace.StartSpan(ctx, "GetChainMessages")
defer span.End()
req := &Request{
Head: head.Cids(),
Length: length,
Options: Messages,
}
validRes, err := client.doRequest(ctx, req, nil)
if err != nil {
return nil, err
}
return validRes.messages, nil
}
// Send a request to a peer. Write request in the stream and read the
// response back. We do not do any processing of the request/response
// here.
func (client *BlockSync) sendRequestToPeer(
ctx context.Context,
peer peer.ID,
req *Request,
) (_ *Response, err error) {
// Trace code.
ctx, span := trace.StartSpan(ctx, "sendRequestToPeer")
defer span.End()
if span.IsRecordingEvents() {
span.AddAttributes(
trace.StringAttribute("peer", peer.Pretty()),
)
}
defer func() {
if err != nil {
if span.IsRecordingEvents() {
span.SetStatus(trace.Status{
Code: 5,
Message: err.Error(),
})
}
}
}()
// -- TRACE --
supported, err := client.host.Peerstore().SupportsProtocols(peer, BlockSyncProtocolID)
if err != nil {
return nil, xerrors.Errorf("failed to get protocols for peer: %w", err)
}
if len(supported) == 0 || supported[0] != BlockSyncProtocolID {
return nil, xerrors.Errorf("peer %s does not support protocol %s",
peer, BlockSyncProtocolID)
// FIXME: `ProtoBook` should support a *single* protocol check that returns
// a bool instead of a list.
}
connectionStart := build.Clock.Now()
// Open stream to peer.
stream, err := client.host.NewStream(
inet.WithNoDial(ctx, "should already have connection"),
peer,
BlockSyncProtocolID)
if err != nil {
client.RemovePeer(peer)
return nil, xerrors.Errorf("failed to open stream to peer: %w", err)
}
// Write request.
_ = stream.SetWriteDeadline(time.Now().Add(WRITE_REQ_DEADLINE))
if err := cborutil.WriteCborRPC(stream, req); err != nil {
_ = stream.SetWriteDeadline(time.Time{})
client.peerTracker.logFailure(peer, build.Clock.Since(connectionStart))
// FIXME: Should we also remove peer here?
return nil, err
}
_ = stream.SetWriteDeadline(time.Time{}) // clear deadline // FIXME: Needs
// its own API (https://github.com/libp2p/go-libp2p-core/issues/162).
// Read response.
var res Response
err = cborutil.ReadCborRPC(
bufio.NewReader(incrt.New(stream, READ_RES_MIN_SPEED, READ_RES_DEADLINE)),
&res)
if err != nil {
client.peerTracker.logFailure(peer, build.Clock.Since(connectionStart))
return nil, xerrors.Errorf("failed to read blocksync response: %w", err)
}
// FIXME: Move all this together at the top using a defer as done elsewhere.
// Maybe we need to declare `res` in the signature.
if span.IsRecordingEvents() {
span.AddAttributes(
trace.Int64Attribute("resp_status", int64(res.Status)),
trace.StringAttribute("msg", res.ErrorMessage),
trace.Int64Attribute("chain_len", int64(len(res.Chain))),
)
}
client.peerTracker.logSuccess(peer, build.Clock.Since(connectionStart))
// FIXME: We should really log a success only after we validate the response.
// It might be a bit hard to do.
return &res, nil
}
func (client *BlockSync) AddPeer(p peer.ID) {
client.peerTracker.addPeer(p)
}
func (client *BlockSync) RemovePeer(p peer.ID) {
client.peerTracker.removePeer(p)
}
// getShuffledPeers returns a preference-sorted set of peers (by latency
// and failure counting), shuffling the first few peers so we don't always
// pick the same peer.
// FIXME: Consider merging with `shufflePrefix()s`.
func (client *BlockSync) getShuffledPeers() []peer.ID {
peers := client.peerTracker.prefSortedPeers()
shufflePrefix(peers)
return peers
}
func shufflePrefix(peers []peer.ID) {
prefix := SHUFFLE_PEERS_PREFIX
if len(peers) < prefix {
prefix = len(peers)
}
buf := make([]peer.ID, prefix)
perm := rand.Perm(prefix)
for i, v := range perm {
buf[i] = peers[v]
}
copy(peers, buf)
}