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package server
import (
"bufio"
"context"
"fmt"
"io"
"net"
"runtime"
"sync"
"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"
)
// var maxNumberConnections = 2
type SocketServer struct {
service.BaseService
logger log.Logger
proto string
addr string
listener net.Listener
connsMtx sync.Mutex
conns map[int]net.Conn
nextConnID int
appMtx sync.Mutex
app types.Application
}
func NewSocketServer(logger log.Logger, protoAddr string, app types.Application) service.Service {
proto, addr := tmnet.ProtocolAndAddress(protoAddr)
s := &SocketServer{
logger: logger,
proto: proto,
addr: addr,
listener: nil,
app: app,
conns: make(map[int]net.Conn),
}
s.BaseService = *service.NewBaseService(logger, "ABCIServer", s)
return s
}
func (s *SocketServer) OnStart(ctx context.Context) error {
ln, err := net.Listen(s.proto, s.addr)
if err != nil {
return err
}
s.listener = ln
go s.acceptConnectionsRoutine(ctx)
return nil
}
func (s *SocketServer) OnStop() {
if err := s.listener.Close(); err != nil {
s.logger.Error("error closing listener", "err", err)
}
s.connsMtx.Lock()
defer s.connsMtx.Unlock()
for id, conn := range s.conns {
delete(s.conns, id)
if err := conn.Close(); err != nil {
s.logger.Error("error closing connection", "id", id, "conn", conn, "err", err)
}
}
}
func (s *SocketServer) addConn(conn net.Conn) int {
s.connsMtx.Lock()
defer s.connsMtx.Unlock()
connID := s.nextConnID
s.nextConnID++
s.conns[connID] = conn
return connID
}
// deletes conn even if close errs
func (s *SocketServer) rmConn(connID int) error {
s.connsMtx.Lock()
defer s.connsMtx.Unlock()
conn, ok := s.conns[connID]
if !ok {
return fmt.Errorf("connection %d does not exist", connID)
}
delete(s.conns, connID)
return conn.Close()
}
func (s *SocketServer) acceptConnectionsRoutine(ctx context.Context) {
for {
if ctx.Err() != nil {
return
}
// Accept a connection
s.logger.Info("Waiting for new connection...")
conn, err := s.listener.Accept()
if err != nil {
if !s.IsRunning() {
return // Ignore error from listener closing.
}
s.logger.Error("Failed to accept connection", "err", err)
continue
}
s.logger.Info("Accepted a new connection")
connID := s.addConn(conn)
closeConn := make(chan error, 2) // Push to signal connection closed
responses := make(chan *types.Response, 1000) // A channel to buffer responses
// Read requests from conn and deal with them
go s.handleRequests(ctx, closeConn, conn, responses)
// Pull responses from 'responses' and write them to conn.
go s.handleResponses(ctx, closeConn, conn, responses)
// Wait until signal to close connection
go s.waitForClose(ctx, closeConn, connID)
}
}
func (s *SocketServer) waitForClose(ctx context.Context, closeConn chan error, connID int) {
defer func() {
// Close the connection
if err := s.rmConn(connID); err != nil {
s.logger.Error("error closing connection", "err", err)
}
}()
select {
case <-ctx.Done():
return
case err := <-closeConn:
switch {
case err == io.EOF:
s.logger.Error("Connection was closed by client")
case err != nil:
s.logger.Error("Connection error", "err", err)
default:
// never happens
s.logger.Error("Connection was closed")
}
}
}
// Read requests from conn and deal with them
func (s *SocketServer) handleRequests(
ctx context.Context,
closeConn chan error,
conn io.Reader,
responses chan<- *types.Response,
) {
var count int
var bufReader = bufio.NewReader(conn)
defer func() {
// make sure to recover from any app-related panics to allow proper socket cleanup
r := recover()
if r != nil {
const size = 64 << 10
buf := make([]byte, size)
buf = buf[:runtime.Stack(buf, false)]
err := fmt.Errorf("recovered from panic: %v\n%s", r, buf)
closeConn <- err
s.appMtx.Unlock()
}
}()
for {
if ctx.Err() != nil {
return
}
var req = &types.Request{}
err := types.ReadMessage(bufReader, req)
if err != nil {
if err == io.EOF {
closeConn <- err
} else {
closeConn <- fmt.Errorf("error reading message: %w", err)
}
return
}
s.appMtx.Lock()
count++
s.handleRequest(req, responses)
s.appMtx.Unlock()
}
}
func (s *SocketServer) handleRequest(req *types.Request, responses chan<- *types.Response) {
switch r := req.Value.(type) {
case *types.Request_Echo:
responses <- types.ToResponseEcho(r.Echo.Message)
case *types.Request_Flush:
responses <- types.ToResponseFlush()
case *types.Request_Info:
res := s.app.Info(*r.Info)
responses <- types.ToResponseInfo(res)
case *types.Request_DeliverTx:
res := s.app.DeliverTx(*r.DeliverTx)
responses <- types.ToResponseDeliverTx(res)
case *types.Request_CheckTx:
res := s.app.CheckTx(*r.CheckTx)
responses <- types.ToResponseCheckTx(res)
case *types.Request_Commit:
res := s.app.Commit()
responses <- types.ToResponseCommit(res)
case *types.Request_Query:
res := s.app.Query(*r.Query)
responses <- types.ToResponseQuery(res)
case *types.Request_InitChain:
res := s.app.InitChain(*r.InitChain)
responses <- types.ToResponseInitChain(res)
case *types.Request_BeginBlock:
res := s.app.BeginBlock(*r.BeginBlock)
responses <- types.ToResponseBeginBlock(res)
case *types.Request_EndBlock:
res := s.app.EndBlock(*r.EndBlock)
responses <- types.ToResponseEndBlock(res)
case *types.Request_ListSnapshots:
res := s.app.ListSnapshots(*r.ListSnapshots)
responses <- types.ToResponseListSnapshots(res)
case *types.Request_OfferSnapshot:
res := s.app.OfferSnapshot(*r.OfferSnapshot)
responses <- types.ToResponseOfferSnapshot(res)
case *types.Request_LoadSnapshotChunk:
res := s.app.LoadSnapshotChunk(*r.LoadSnapshotChunk)
responses <- types.ToResponseLoadSnapshotChunk(res)
case *types.Request_ApplySnapshotChunk:
res := s.app.ApplySnapshotChunk(*r.ApplySnapshotChunk)
responses <- types.ToResponseApplySnapshotChunk(res)
default:
responses <- types.ToResponseException("Unknown request")
}
}
// Pull responses from 'responses' and write them to conn.
func (s *SocketServer) handleResponses(
ctx context.Context,
closeConn chan error,
conn io.Writer,
responses <-chan *types.Response,
) {
bw := bufio.NewWriter(conn)
for {
select {
case <-ctx.Done():
return
case res := <-responses:
if err := types.WriteMessage(res, bw); err != nil {
select {
case <-ctx.Done():
case closeConn <- fmt.Errorf("error writing message: %w", err):
}
return
}
if err := bw.Flush(); err != nil {
select {
case <-ctx.Done():
case closeConn <- fmt.Errorf("error flushing write buffer: %w", err):
}
return
}
}
}
}