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) EchoAsync(ctx context.Context, msg string) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestEcho(msg)) } func (cli *socketClient) FlushAsync(ctx context.Context) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestFlush()) } func (cli *socketClient) InfoAsync(ctx context.Context, req types.RequestInfo) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestInfo(req)) } 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) QueryAsync(ctx context.Context, req types.RequestQuery) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestQuery(req)) } func (cli *socketClient) CommitAsync(ctx context.Context) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestCommit()) } func (cli *socketClient) InitChainAsync(ctx context.Context, req types.RequestInitChain) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestInitChain(req)) } func (cli *socketClient) BeginBlockAsync(ctx context.Context, req types.RequestBeginBlock) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestBeginBlock(req)) } func (cli *socketClient) EndBlockAsync(ctx context.Context, req types.RequestEndBlock) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestEndBlock(req)) } func (cli *socketClient) ListSnapshotsAsync(ctx context.Context, req types.RequestListSnapshots) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestListSnapshots(req)) } func (cli *socketClient) OfferSnapshotAsync(ctx context.Context, req types.RequestOfferSnapshot) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestOfferSnapshot(req)) } func (cli *socketClient) LoadSnapshotChunkAsync( ctx context.Context, req types.RequestLoadSnapshotChunk, ) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestLoadSnapshotChunk(req)) } func (cli *socketClient) ApplySnapshotChunkAsync( ctx context.Context, req types.RequestApplySnapshotChunk, ) (*ReqRes, error) { return cli.queueRequestAsync(ctx, types.ToRequestApplySnapshotChunk(req)) } //---------------------------------------- func (cli *socketClient) FlushSync(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) EchoSync(ctx context.Context, msg string) (*types.ResponseEcho, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestEcho(msg)) if err != nil { return nil, err } return reqres.Response.GetEcho(), nil } func (cli *socketClient) InfoSync( ctx context.Context, req types.RequestInfo, ) (*types.ResponseInfo, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestInfo(req)) if err != nil { return nil, err } return reqres.Response.GetInfo(), nil } func (cli *socketClient) DeliverTxSync( ctx context.Context, req types.RequestDeliverTx, ) (*types.ResponseDeliverTx, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestDeliverTx(req)) if err != nil { return nil, err } return reqres.Response.GetDeliverTx(), nil } func (cli *socketClient) CheckTxSync( ctx context.Context, req types.RequestCheckTx, ) (*types.ResponseCheckTx, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestCheckTx(req)) if err != nil { return nil, err } return reqres.Response.GetCheckTx(), nil } func (cli *socketClient) QuerySync( ctx context.Context, req types.RequestQuery, ) (*types.ResponseQuery, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestQuery(req)) if err != nil { return nil, err } return reqres.Response.GetQuery(), nil } func (cli *socketClient) CommitSync(ctx context.Context) (*types.ResponseCommit, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestCommit()) if err != nil { return nil, err } return reqres.Response.GetCommit(), nil } func (cli *socketClient) InitChainSync( ctx context.Context, req types.RequestInitChain, ) (*types.ResponseInitChain, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestInitChain(req)) if err != nil { return nil, err } return reqres.Response.GetInitChain(), nil } func (cli *socketClient) BeginBlockSync( ctx context.Context, req types.RequestBeginBlock, ) (*types.ResponseBeginBlock, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestBeginBlock(req)) if err != nil { return nil, err } return reqres.Response.GetBeginBlock(), nil } func (cli *socketClient) EndBlockSync( ctx context.Context, req types.RequestEndBlock, ) (*types.ResponseEndBlock, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestEndBlock(req)) if err != nil { return nil, err } return reqres.Response.GetEndBlock(), nil } func (cli *socketClient) ListSnapshotsSync( ctx context.Context, req types.RequestListSnapshots, ) (*types.ResponseListSnapshots, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestListSnapshots(req)) if err != nil { return nil, err } return reqres.Response.GetListSnapshots(), nil } func (cli *socketClient) OfferSnapshotSync( ctx context.Context, req types.RequestOfferSnapshot, ) (*types.ResponseOfferSnapshot, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestOfferSnapshot(req)) if err != nil { return nil, err } return reqres.Response.GetOfferSnapshot(), nil } func (cli *socketClient) LoadSnapshotChunkSync( ctx context.Context, req types.RequestLoadSnapshotChunk) (*types.ResponseLoadSnapshotChunk, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestLoadSnapshotChunk(req)) if err != nil { return nil, err } return reqres.Response.GetLoadSnapshotChunk(), nil } func (cli *socketClient) ApplySnapshotChunkSync( ctx context.Context, req types.RequestApplySnapshotChunk) (*types.ResponseApplySnapshotChunk, error) { reqres, err := cli.queueRequestAndFlushSync(ctx, types.ToRequestApplySnapshotChunk(req)) if err != nil { return nil, err } return reqres.Response.GetApplySnapshotChunk(), 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) queueRequestAndFlushSync( 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.FlushSync(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_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) } }