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package abciclient
import (
"bufio"
"container/list"
"context"
"errors"
"fmt"
"io"
"net"
"reflect"
"sync"
"time"
"github.com/tendermint/tendermint/abci/types"
"github.com/tendermint/tendermint/libs/log"
tmnet "github.com/tendermint/tendermint/libs/net"
"github.com/tendermint/tendermint/libs/service"
)
const (
// reqQueueSize is the max number of queued async requests.
// (memory: 256MB max assuming 1MB transactions)
reqQueueSize = 256
)
type reqResWithContext struct {
R *ReqRes
C context.Context // if context.Err is not nil, reqRes will be thrown away (ignored)
}
// This is goroutine-safe, but users should beware that the application in
// general is not meant to be interfaced with concurrent callers.
type socketClient struct {
service.BaseService
logger log.Logger
addr string
mustConnect bool
conn net.Conn
reqQueue chan *reqResWithContext
mtx sync.Mutex
err error
reqSent *list.List // list of requests sent, waiting for response
resCb func(*types.Request, *types.Response) // called on all requests, if set.
}
var _ Client = (*socketClient)(nil)
// NewSocketClient creates a new socket client, which connects to a given
// address. If mustConnect is true, the client will return an error upon start
// if it fails to connect.
func NewSocketClient(logger log.Logger, addr string, mustConnect bool) Client {
cli := &socketClient{
logger: logger,
reqQueue: make(chan *reqResWithContext, reqQueueSize),
mustConnect: mustConnect,
addr: addr,
reqSent: list.New(),
resCb: nil,
}
cli.BaseService = *service.NewBaseService(logger, "socketClient", cli)
return cli
}
// OnStart implements Service by connecting to the server and spawning reading
// and writing goroutines.
func (cli *socketClient) OnStart(ctx context.Context) error {
var (
err error
conn net.Conn
)
for {
conn, err = tmnet.Connect(cli.addr)
if err != nil {
if cli.mustConnect {
return err
}
cli.logger.Error(fmt.Sprintf("abci.socketClient failed to connect to %v. Retrying after %vs...",
cli.addr, dialRetryIntervalSeconds), "err", err)
time.Sleep(time.Second * dialRetryIntervalSeconds)
continue
}
cli.conn = conn
go cli.sendRequestsRoutine(ctx, conn)
go cli.recvResponseRoutine(ctx, conn)
return nil
}
}
// OnStop implements Service by closing connection and flushing all queues.
func (cli *socketClient) OnStop() {
if cli.conn != nil {
cli.conn.Close()
}
cli.drainQueue()
}
// Error returns an error if the client was stopped abruptly.
func (cli *socketClient) Error() error {
cli.mtx.Lock()
defer cli.mtx.Unlock()
return cli.err
}
// SetResponseCallback sets a callback, which will be executed for each
// non-error & non-empty response from the server.
//
// NOTE: callback may get internally generated flush responses.
func (cli *socketClient) SetResponseCallback(resCb Callback) {
cli.mtx.Lock()
defer cli.mtx.Unlock()
cli.resCb = resCb
}
//----------------------------------------
func (cli *socketClient) sendRequestsRoutine(ctx context.Context, conn io.Writer) {
bw := bufio.NewWriter(conn)
for {
select {
case <-ctx.Done():
return
case reqres := <-cli.reqQueue:
if ctx.Err() != nil {
return
}
if reqres.C.Err() != nil {
cli.logger.Debug("Request's context is done", "req", reqres.R, "err", reqres.C.Err())
continue
}
cli.willSendReq(reqres.R)
if err := types.WriteMessage(reqres.R.Request, bw); err != nil {
cli.stopForError(fmt.Errorf("write to buffer: %w", err))
return
}
if err := bw.Flush(); err != nil {
cli.stopForError(fmt.Errorf("flush buffer: %w", err))
return
}
}
}
}
func (cli *socketClient) recvResponseRoutine(ctx context.Context, conn io.Reader) {
r := bufio.NewReader(conn)
for {
if ctx.Err() != nil {
return
}
var res = &types.Response{}
err := types.ReadMessage(r, res)
if err != nil {
cli.stopForError(fmt.Errorf("read message: %w", err))
return
}
// cli.logger.Debug("Received response", "responseType", reflect.TypeOf(res), "response", res)
switch r := res.Value.(type) {
case *types.Response_Exception: // app responded with error
// XXX After setting cli.err, release waiters (e.g. reqres.Done())
cli.stopForError(errors.New(r.Exception.Error))
return
default:
err := cli.didRecvResponse(res)
if err != nil {
cli.stopForError(err)
return
}
}
}
}
func (cli *socketClient) willSendReq(reqres *ReqRes) {
cli.mtx.Lock()
defer cli.mtx.Unlock()
cli.reqSent.PushBack(reqres)
}
func (cli *socketClient) didRecvResponse(res *types.Response) error {
cli.mtx.Lock()
defer cli.mtx.Unlock()
// Get the first ReqRes.
next := cli.reqSent.Front()
if next == nil {
return fmt.Errorf("unexpected %v when nothing expected", reflect.TypeOf(res.Value))
}
reqres := next.Value.(*ReqRes)
if !resMatchesReq(reqres.Request, res) {
return fmt.Errorf("unexpected %v when response to %v expected",
reflect.TypeOf(res.Value), reflect.TypeOf(reqres.Request.Value))
}
reqres.Response = res
reqres.Done() // release waiters
cli.reqSent.Remove(next) // pop first item from linked list
// Notify client listener if set (global callback).
if cli.resCb != nil {
cli.resCb(reqres.Request, res)
}
// Notify reqRes listener if set (request specific callback).
//
// NOTE: It is possible this callback isn't set on the reqres object. At this
// point, in which case it will be called after, when it is set.
reqres.InvokeCallback()
return nil
}
//----------------------------------------
func (cli *socketClient) FlushAsync(ctx context.Context) (*ReqRes, error) {
return cli.queueRequestAsync(ctx, types.ToRequestFlush())
}
func (cli *socketClient) DeliverTxAsync(ctx context.Context, req types.RequestDeliverTx) (*ReqRes, error) {
return cli.queueRequestAsync(ctx, types.ToRequestDeliverTx(req))
}
func (cli *socketClient) CheckTxAsync(ctx context.Context, req types.RequestCheckTx) (*ReqRes, error) {
return cli.queueRequestAsync(ctx, types.ToRequestCheckTx(req))
}
//----------------------------------------
func (cli *socketClient) Flush(ctx context.Context) error {
reqRes, err := cli.queueRequest(ctx, types.ToRequestFlush(), true)
if err != nil {
return queueErr(err)
}
if err := cli.Error(); err != nil {
return err
}
gotResp := make(chan struct{})
go func() {
// NOTE: if we don't flush the queue, its possible to get stuck here
reqRes.Wait()
close(gotResp)
}()
select {
case <-gotResp:
return cli.Error()
case <-ctx.Done():
return ctx.Err()
}
}
func (cli *socketClient) Echo(ctx context.Context, msg string) (*types.ResponseEcho, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestEcho(msg))
if err != nil {
return nil, err
}
return reqres.Response.GetEcho(), nil
}
func (cli *socketClient) Info(
ctx context.Context,
req types.RequestInfo,
) (*types.ResponseInfo, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestInfo(req))
if err != nil {
return nil, err
}
return reqres.Response.GetInfo(), nil
}
func (cli *socketClient) DeliverTx(
ctx context.Context,
req types.RequestDeliverTx,
) (*types.ResponseDeliverTx, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestDeliverTx(req))
if err != nil {
return nil, err
}
return reqres.Response.GetDeliverTx(), nil
}
func (cli *socketClient) CheckTx(
ctx context.Context,
req types.RequestCheckTx,
) (*types.ResponseCheckTx, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestCheckTx(req))
if err != nil {
return nil, err
}
return reqres.Response.GetCheckTx(), nil
}
func (cli *socketClient) Query(
ctx context.Context,
req types.RequestQuery,
) (*types.ResponseQuery, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestQuery(req))
if err != nil {
return nil, err
}
return reqres.Response.GetQuery(), nil
}
func (cli *socketClient) Commit(ctx context.Context) (*types.ResponseCommit, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestCommit())
if err != nil {
return nil, err
}
return reqres.Response.GetCommit(), nil
}
func (cli *socketClient) InitChain(
ctx context.Context,
req types.RequestInitChain,
) (*types.ResponseInitChain, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestInitChain(req))
if err != nil {
return nil, err
}
return reqres.Response.GetInitChain(), nil
}
func (cli *socketClient) BeginBlock(
ctx context.Context,
req types.RequestBeginBlock,
) (*types.ResponseBeginBlock, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestBeginBlock(req))
if err != nil {
return nil, err
}
return reqres.Response.GetBeginBlock(), nil
}
func (cli *socketClient) EndBlock(
ctx context.Context,
req types.RequestEndBlock,
) (*types.ResponseEndBlock, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestEndBlock(req))
if err != nil {
return nil, err
}
return reqres.Response.GetEndBlock(), nil
}
func (cli *socketClient) ListSnapshots(
ctx context.Context,
req types.RequestListSnapshots,
) (*types.ResponseListSnapshots, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestListSnapshots(req))
if err != nil {
return nil, err
}
return reqres.Response.GetListSnapshots(), nil
}
func (cli *socketClient) OfferSnapshot(
ctx context.Context,
req types.RequestOfferSnapshot,
) (*types.ResponseOfferSnapshot, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestOfferSnapshot(req))
if err != nil {
return nil, err
}
return reqres.Response.GetOfferSnapshot(), nil
}
func (cli *socketClient) LoadSnapshotChunk(
ctx context.Context,
req types.RequestLoadSnapshotChunk) (*types.ResponseLoadSnapshotChunk, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestLoadSnapshotChunk(req))
if err != nil {
return nil, err
}
return reqres.Response.GetLoadSnapshotChunk(), nil
}
func (cli *socketClient) ApplySnapshotChunk(
ctx context.Context,
req types.RequestApplySnapshotChunk) (*types.ResponseApplySnapshotChunk, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestApplySnapshotChunk(req))
if err != nil {
return nil, err
}
return reqres.Response.GetApplySnapshotChunk(), nil
}
func (cli *socketClient) PrepareProposal(
ctx context.Context,
req types.RequestPrepareProposal) (*types.ResponsePrepareProposal, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestPrepareProposal(req))
if err != nil {
return nil, err
}
return reqres.Response.GetPrepareProposal(), nil
}
func (cli *socketClient) ProcessProposal(
ctx context.Context,
req types.RequestProcessProposal,
) (*types.ResponseProcessProposal, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestProcessProposal(req))
if err != nil {
return nil, err
}
return reqres.Response.GetProcessProposal(), nil
}
func (cli *socketClient) ExtendVote(
ctx context.Context,
req types.RequestExtendVote) (*types.ResponseExtendVote, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestExtendVote(req))
if err != nil {
return nil, err
}
return reqres.Response.GetExtendVote(), nil
}
func (cli *socketClient) VerifyVoteExtension(
ctx context.Context,
req types.RequestVerifyVoteExtension) (*types.ResponseVerifyVoteExtension, error) {
reqres, err := cli.queueRequestAndFlush(ctx, types.ToRequestVerifyVoteExtension(req))
if err != nil {
return nil, err
}
return reqres.Response.GetVerifyVoteExtension(), nil
}
//----------------------------------------
// queueRequest enqueues req onto the queue. If the queue is full, it ether
// returns an error (sync=false) or blocks (sync=true).
//
// When sync=true, ctx can be used to break early. When sync=false, ctx will be
// used later to determine if request should be dropped (if ctx.Err is
// non-nil).
//
// The caller is responsible for checking cli.Error.
func (cli *socketClient) queueRequest(ctx context.Context, req *types.Request, sync bool) (*ReqRes, error) {
reqres := NewReqRes(req)
if sync {
select {
case cli.reqQueue <- &reqResWithContext{R: reqres, C: context.Background()}:
case <-ctx.Done():
return nil, ctx.Err()
}
} else {
select {
case cli.reqQueue <- &reqResWithContext{R: reqres, C: ctx}:
default:
return nil, errors.New("buffer is full")
}
}
return reqres, nil
}
func (cli *socketClient) queueRequestAsync(
ctx context.Context,
req *types.Request,
) (*ReqRes, error) {
reqres, err := cli.queueRequest(ctx, req, false)
if err != nil {
return nil, queueErr(err)
}
return reqres, cli.Error()
}
func (cli *socketClient) queueRequestAndFlush(
ctx context.Context,
req *types.Request,
) (*ReqRes, error) {
reqres, err := cli.queueRequest(ctx, req, true)
if err != nil {
return nil, queueErr(err)
}
if err := cli.Flush(ctx); err != nil {
return nil, err
}
return reqres, cli.Error()
}
func queueErr(e error) error {
return fmt.Errorf("can't queue req: %w", e)
}
// drainQueue marks as complete and discards all remaining pending requests
// from the queue.
func (cli *socketClient) drainQueue() {
cli.mtx.Lock()
defer cli.mtx.Unlock()
// mark all in-flight messages as resolved (they will get cli.Error())
for req := cli.reqSent.Front(); req != nil; req = req.Next() {
reqres := req.Value.(*ReqRes)
reqres.Done()
}
// Mark all queued messages as resolved.
//
// TODO(creachadair): We can't simply range the channel, because it is never
// closed, and the writer continues to add work.
// See https://github.com/tendermint/tendermint/issues/6996.
for {
select {
case reqres := <-cli.reqQueue:
reqres.R.Done()
default:
return
}
}
}
//----------------------------------------
func resMatchesReq(req *types.Request, res *types.Response) (ok bool) {
switch req.Value.(type) {
case *types.Request_Echo:
_, ok = res.Value.(*types.Response_Echo)
case *types.Request_Flush:
_, ok = res.Value.(*types.Response_Flush)
case *types.Request_Info:
_, ok = res.Value.(*types.Response_Info)
case *types.Request_DeliverTx:
_, ok = res.Value.(*types.Response_DeliverTx)
case *types.Request_CheckTx:
_, ok = res.Value.(*types.Response_CheckTx)
case *types.Request_Commit:
_, ok = res.Value.(*types.Response_Commit)
case *types.Request_Query:
_, ok = res.Value.(*types.Response_Query)
case *types.Request_InitChain:
_, ok = res.Value.(*types.Response_InitChain)
case *types.Request_PrepareProposal:
_, ok = res.Value.(*types.Response_PrepareProposal)
case *types.Request_ExtendVote:
_, ok = res.Value.(*types.Response_ExtendVote)
case *types.Request_VerifyVoteExtension:
_, ok = res.Value.(*types.Response_VerifyVoteExtension)
case *types.Request_BeginBlock:
_, ok = res.Value.(*types.Response_BeginBlock)
case *types.Request_EndBlock:
_, ok = res.Value.(*types.Response_EndBlock)
case *types.Request_ApplySnapshotChunk:
_, ok = res.Value.(*types.Response_ApplySnapshotChunk)
case *types.Request_LoadSnapshotChunk:
_, ok = res.Value.(*types.Response_LoadSnapshotChunk)
case *types.Request_ListSnapshots:
_, ok = res.Value.(*types.Response_ListSnapshots)
case *types.Request_OfferSnapshot:
_, ok = res.Value.(*types.Response_OfferSnapshot)
}
return ok
}
func (cli *socketClient) stopForError(err error) {
if !cli.IsRunning() {
return
}
cli.mtx.Lock()
cli.err = err
cli.mtx.Unlock()
cli.logger.Info("Stopping abci.socketClient", "reason", err)
if err := cli.Stop(); err != nil {
cli.logger.Error("error stopping abci.socketClient", "err", err)
}
}