Golang BatchResponse.Txn方法代碼示例

// sendBatch unrolls a batched command and sends each constituent
// command in parallel.
// TODO(tschottdorf): modify sendBatch so that it sends truly parallel requests
// when outside of a Transaction. This can then be used to address the TODO in
// (*TxnCoordSender).resolve().
func (tc *TxnCoordSender) sendBatch(ctx context.Context, batchArgs *proto.BatchRequest, batchReply *proto.BatchResponse) {
	// 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)
		if err := updateForBatch(args, batchArgs.RequestHeader); err != nil {
			batchReply.Header().SetGoError(err)
			return
		}
		call := proto.Call{Args: args}
		// 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(ctx, 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
		}
	}
}

func newTestSender(pre, post func(proto.BatchRequest) (*proto.BatchResponse, *proto.Error)) SenderFunc {
	txnKey := proto.Key("test-txn")
	txnID := []byte(uuid.NewUUID4())

	return func(_ context.Context, ba proto.BatchRequest) (*proto.BatchResponse, *proto.Error) {
		ba.UserPriority = gogoproto.Int32(-1)
		if ba.Txn != nil && len(ba.Txn.ID) == 0 {
			ba.Txn.Key = txnKey
			ba.Txn.ID = txnID
		}

		var br *proto.BatchResponse
		var pErr *proto.Error
		if pre != nil {
			br, pErr = pre(ba)
		} else {
			br = &proto.BatchResponse{}
		}
		if pErr != nil {
			return nil, pErr
		}
		var writing bool
		status := proto.PENDING
		if _, ok := ba.GetArg(proto.Put); ok {
			br.Add(gogoproto.Clone(testPutResp).(proto.Response))
			writing = true
		}
		if args, ok := ba.GetArg(proto.EndTransaction); ok {
			et := args.(*proto.EndTransactionRequest)
			writing = true
			if et.Commit {
				status = proto.COMMITTED
			} else {
				status = proto.ABORTED
			}
		}
		br.Txn = gogoproto.Clone(ba.Txn).(*proto.Transaction)
		if br.Txn != nil && pErr == nil {
			br.Txn.Writing = writing
			br.Txn.Status = status
		}

		if post != nil {
			br, pErr = post(ba)
		}
		return br, pErr
	}
}

// sendBatch unrolls a batched command and sends each constituent
// command in parallel.
func (tc *TxnCoordSender) sendBatch(batchArgs *proto.BatchRequest, batchReply *proto.BatchResponse) {
	// 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 {
		// Initialize args header values where appropriate.
		args := batchArgs.Requests[i].GetValue().(proto.Request)
		method, err := proto.MethodForRequest(args)
		call := &client.Call{Method: method, Args: args}
		if err != nil {
			batchReply.SetGoError(err)
			return
		}
		if args.Header().User == "" {
			args.Header().User = batchArgs.User
		}
		if args.Header().UserPriority == nil {
			args.Header().UserPriority = batchArgs.UserPriority
		}
		args.Header().Txn = batchArgs.Txn

		// Create a reply from the method type and add to batch response.
		if i >= len(batchReply.Responses) {
			if call.Reply, err = proto.CreateReply(method); err != nil {
				batchReply.SetGoError(util.Errorf("unsupported method in batch: %s", method))
				return
			}
			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
		}
	}
}

// TODO(tschottdorf): this method is somewhat awkward but unless we want to
// give this error back to the client, our options are limited. We'll have to
// run the whole thing for them, or any restart will still end up at the client
// which will not be prepared to be handed a Txn.
func (tc *TxnCoordSender) resendWithTxn(ba proto.BatchRequest) (*proto.BatchResponse, *proto.Error) {
	// Run a one-off transaction with that single command.
	if log.V(1) {
		log.Infof("%s: auto-wrapping in txn and re-executing: ", ba)
	}
	tmpDB := client.NewDBWithPriority(tc, ba.GetUserPriority())
	var br *proto.BatchResponse
	err := tmpDB.Txn(func(txn *client.Txn) error {
		txn.SetDebugName("auto-wrap", 0)
		b := &client.Batch{}
		for _, arg := range ba.Requests {
			req := arg.GetInner()
			b.InternalAddRequest(req)
		}
		var err error
		br, err = txn.CommitInBatchWithResponse(b)
		return err
	})
	if err != nil {
		return nil, proto.NewError(err)
	}
	br.Txn = nil // hide the evidence
	return br, nil
}

// updateState updates the transaction state in both the success and
// error cases, applying those updates to the corresponding txnMeta
// object when adequate. It also updates certain errors with the
// updated transaction for use by client restarts.
func (tc *TxnCoordSender) updateState(ctx context.Context, ba proto.BatchRequest, br *proto.BatchResponse, pErr *proto.Error) *proto.Error {
	trace := tracer.FromCtx(ctx)
	newTxn := &proto.Transaction{}
	newTxn.Update(ba.GetTxn())
	err := pErr.GoError()
	switch t := err.(type) {
	case nil:
		newTxn.Update(br.GetTxn())
		// Move txn timestamp forward to response timestamp if applicable.
		// TODO(tschottdorf): see (*Replica).executeBatch and comments within.
		// Looks like this isn't necessary any more, nor did it prevent a bug
		// referenced in a TODO there.
		newTxn.Timestamp.Forward(br.Timestamp)
	case *proto.TransactionStatusError:
		// Likely already committed or more obscure errors such as epoch or
		// timestamp regressions; consider txn dead.
		defer tc.cleanupTxn(trace, t.Txn)
	case *proto.OpRequiresTxnError:
		// TODO(tschottdorf): range-spanning autowrap currently broken.
		panic("TODO(tschottdorf): disabled")
	case *proto.ReadWithinUncertaintyIntervalError:
		// Mark the host as certain. See the protobuf comment for
		// Transaction.CertainNodes for details.
		if t.NodeID == 0 {
			panic("no replica set in header on uncertainty restart")
		}
		newTxn.CertainNodes.Add(t.NodeID)
		// If the reader encountered a newer write within the uncertainty
		// interval, move the timestamp forward, just past that write or
		// up to MaxTimestamp, whichever comes first.
		candidateTS := newTxn.MaxTimestamp
		candidateTS.Backward(t.ExistingTimestamp.Add(0, 1))
		newTxn.Timestamp.Forward(candidateTS)
		newTxn.Restart(ba.GetUserPriority(), newTxn.Priority, newTxn.Timestamp)
		t.Txn = *newTxn
	case *proto.TransactionAbortedError:
		// Increase timestamp if applicable.
		newTxn.Timestamp.Forward(t.Txn.Timestamp)
		newTxn.Priority = t.Txn.Priority
		t.Txn = *newTxn
		// Clean up the freshly aborted transaction in defer(), avoiding a
		// race with the state update below.
		defer tc.cleanupTxn(trace, t.Txn)
	case *proto.TransactionPushError:
		// Increase timestamp if applicable, ensuring that we're
		// just ahead of the pushee.
		newTxn.Timestamp.Forward(t.PusheeTxn.Timestamp.Add(0, 1))
		newTxn.Restart(ba.GetUserPriority(), t.PusheeTxn.Priority-1, newTxn.Timestamp)
		t.Txn = newTxn
	case *proto.TransactionRetryError:
		// Increase timestamp if applicable.
		newTxn.Timestamp.Forward(t.Txn.Timestamp)
		newTxn.Restart(ba.GetUserPriority(), t.Txn.Priority, newTxn.Timestamp)
		t.Txn = *newTxn
	case proto.TransactionRestartError:
		// Assertion: The above cases should exhaust all ErrorDetails which
		// carry a Transaction.
		if pErr.Detail != nil {
			panic(fmt.Sprintf("unhandled TransactionRestartError %T", err))
		}
	}

	return func() *proto.Error {
		if len(newTxn.ID) <= 0 {
			return pErr
		}
		id := string(newTxn.ID)
		tc.Lock()
		defer tc.Unlock()
		txnMeta := tc.txns[id]
		// For successful transactional requests, keep the written intents and
		// the updated transaction record to be sent along with the reply.
		// The transaction metadata is created with the first writing operation
		// TODO(tschottdorf): already computed the intents prior to sending,
		// consider re-using those.
		if intents := ba.GetIntents(); len(intents) > 0 && err == nil {
			if txnMeta == nil {
				newTxn.Writing = true
				txnMeta = &txnMetadata{
					txn:              *newTxn,
					keys:             cache.NewIntervalCache(cache.Config{Policy: cache.CacheNone}),
					firstUpdateNanos: tc.clock.PhysicalNow(),
					lastUpdateNanos:  tc.clock.PhysicalNow(),
					timeoutDuration:  tc.clientTimeout,
					txnEnd:           make(chan struct{}),
				}
				tc.txns[id] = txnMeta
				// If the transaction is already over, there's no point in
				// launching a one-off coordinator which will shut down right
				// away.
				if _, isEnding := ba.GetArg(proto.EndTransaction); !isEnding {
					trace.Event("coordinator spawns")
					if !tc.stopper.RunAsyncTask(func() {
						tc.heartbeatLoop(id)
					}) {
						// The system is already draining and we can't start the
//.........這裏部分代碼省略.........