ZeroMQ – Transaction Reporting via MetaTrader (ZMQ-III)

In this third installment of our ZeroMQ series, we describe how to use ZeroMQ in non-MQL trading strategies to get the following information:

1. Account Information (e.g. equity, margin, balance, etc)
   
2. Trades at market (live or pending)
3. Historical Trades

Previous posts in this series relied heavily on the Request (REQ) / Reply (REP) communication pattern in ZeroMQ for trading related message exchanges.
Unless transaction information factors into the trading strategy or other critical function, we can safely employ the PUSH/PULL communication pattern for retrieving account and trade-related data from MetaTrader 4.
The ZMQ-enabled MetaTrader EA server published on our GitHub profile implements an example InformPullClient() function that sends information via a PUSH socket to client applications listening at the other end:

void InformPullClient(Socket& pushSocket, string message) {
ZmqMsg pushReply(StringFormat("%s", message));
 pushSocket.send(pushReply,true); // NON-BLOCKING
 // pushSocket.send(pushReply,false); // BLOCKING
}

Any listening applications (e.g. Python/R trading strategies) – in this implementation – will still send requests via the REQ/REP protocol to the ZeroMQ server (MetaTrader EA).
Once received, a request will be parsed into its constituent components and sent through to the Interpreter as usual.

For sake of completeness, here is the diagram describing flow of data between our ZeroMQ clients and servers:

RECAP: Message Topology

Here we’ll dig further into implementing the “ACCOUNT” (account information) and “HISTORY” (trade reporting) formats discussed therein.

Account Information

When it comes to account specifics, traders typically look for the following information:

1. Balance
2. Current P/L
3. Equity
4. Margin Used
5. Free Margin
6. Margin Level
7. Margin Call Level
8. Margin Stop Out Level

For our purposes in this post, we could associate a unique identifier (e.g. numeric values like 1, 2, 3 etc) for each item in the list above.
The corresponding commands sent by an external trading strategy to the ZeroMQ EA in MetaTrader, would then be as follows:

ACCOUNT|1 # balance
ACCOUNT|2 # current P/L
ACCOUNT|3 # equity
ACCOUNT|4 # margin used
ACCOUNT|5 # free margin
ACCOUNT|6 # margin level
ACCOUNT|7 # margin call level
ACCOUNT|8 # margin stop out level

ACCOUNT|0 # all of the above.

Once a message (request for account information) is received, the ZeroMQ EA in MetaTrader will need to parse, interpret and respond accordingly.
Assuming you’re working with the example expert advisor we published in recent posts, you’ll need to implement this message functionality inside the InterpretZmqMessage() function.

As there are several ways to do this, we’ll leave the implementation to the user, but a simple (deliberately inefficient for clarity) example of how to do this, is:

1. Add a condition to check for the “ACCOUNT” leading tag.
   

   if(compArray[0] == "ACCOUNT" && compArray[1] = "0") switch_action = 5;

2. Implement the condition inside the switch() block:
   

   case 5:
    InformPullClient(pSocket, "ACCOUNT Instruction (ALL) Received");

    // IMPLEMENT LOGIC HERE
   string account_info = DoubleToString(AccountInfoDouble(ACCOUNT_BALANCE),2) + "|" +
    DoubleToString(AccountInfoDouble(ACCOUNT_PROFIT),2) + "|" +
    DoubleToString(AccountInfoDouble(ACCOUNT_EQUITY),2) + "|" +
    DoubleToString(AccountInfoDouble(ACCOUNT_MARGIN),2) + "|" +
    DoubleToString(AccountInfoDouble(ACCOUNT_MARGIN_FREE),2) + "|" +
    DoubleToString(AccountInfoDouble(ACCOUNT_MARGIN_LEVEL),2) + "|" +
    DoubleToString(AccountInfoDouble(ACCOUNT_MARGIN_SO_CALL),2) + "|" +
    DoubleToString(AccountInfoDouble(ACCOUNT_MARGIN_SO_SO),2);
   InformPullClient(pSocket, StringFormat("%s", account_info));

The trading strategy – ZeroMQ client –  will retrieve and parse this message via a PULL socket.
Example message received:
1114.73|-2.97|1111.76|10.00|1101.76|11117.60|100.00|50.00
From left to right, this response is interpreted as:
BALANCE | CURRENT P/L | EQUITY | MARGIN IN USE | FREE MARGIN | MARGIN LEVEL | MARGIN CALL LEVEL | MARGIN STOP OUT LEVEL

Trades at Market (live or pending)

For market and pending orders, traders using MetaTrader will typically require the following information:

1. Ticket Number
2. Open Time
3. Type (BUY or SELL)
4. Lot Size (e.g. 0.01, 0.1 and so on)
5. Symbol (e.g. EUR/USD)
6. Open Price (e.g. 1.12000)
7. Stop Loss Price
8. Take Profit Price
9. Commission Paid
10. Swap
11. Current P/L
12. Trade Comment

The fields above are the same (and in the same order) as those displayed in the MetaTrader terminal.
The OrdersTotal() function in MetaTrader is required to retrieve information on trades either currently in execution, or still pending.
In exactly the same manner as used above to retrieve ACCOUNT information, you’ll need to implement additional functionality inside InterpretZmqMessage() for this.
We’ll demonstrate this below using a single message for now:

HISTORY|0 # Retrieve all open pending and market orders.

Once again, as there are several ways to do this, we’ll keep the following example as simple as possible for you to build upon:

1. Add a condition to check for the “HISTORY” leading tag.
   

   if(compArray[0] == "HISTORY" && compArray[1] = "0") switch_action = 6;

2. Implement the condition inside the switch() block:
   

   case 6:
    InformPullClient(pSocket, "Live/Pending Orders Instruction (ALL) Received");

    // IMPLEMENT LOGIC HERE

   int live_orders = OrdersTotal();
   string live_info = "";
   for(int i=0; i < live_orders; i++)
   {
    if(OrderSelect(i,SELECT_BY_POS)==false) continue;
    live_info = live_info + IntegerToString(OrderTicket()) + "," +
     TimeToString(OrderOpenTime()) + "," +
     IntegerToString(OrderType()) + "," +
     DoubleToString(OrderLots(),2) + "," +
     OrderSymbol() + "," +
     DoubleToString(OrderOpenPrice(),5) + "," +
     DoubleToString(OrderStopLoss(),5) + "," +
     DoubleToString(OrderTakeProfit(),5) + "," +
     DoubleToString(OrderCommission(),2) + "," +
     DoubleToString(OrderSwap(),2) + "," +
     DoubleToString(OrderProfit(),2) + "," +
     "<" + OrderComment() + ">|";
   }
   InformPullClient(pSocket, StringFormat("%s", live_info));

The trading strategy – ZeroMQ client –  will retrieve and parse this message via a PULL socket.
Example message received:
12345678,2018.02.16 12:00,1,0.01,USDJPY,100.12300,0.00000,0.00000,-0.05,0.00,-1.23,<My Trading Strategy>|
From left to right, this response is interpreted as:
TICKET, OPEN TIME, TYPE (BUY OR SELL), LOT SIZE, SYMBOL, OPEN PRICE, STOP LOSS PRICE, TAKE PROFIT PRICE, COMMISSION, SWAP, COMMENT

Note #1: There may be more than one trade currently in execution (or pending).
Using the message format above, each such trade will be separated by a “|” character in the output to the receiving client.
Note #2: Order types are returned via MetaTrader’s OrderType() function, as integer values, corresponding to:
OP_BUY – buy order,
OP_SELL – sell order,
OP_BUYLIMIT – buy limit pending order,
OP_BUYSTOP – buy stop pending order,
OP_SELLLIMIT – sell limit pending order,
OP_SELLSTOP – sell stop pending order.

Historical Trades

Retrieving historical trades from MetaTrader is a matter of changing the relevant function to OrdersHistoryTotal() and implementing a near-similar modification to InterpretZmqMessage() as shown above for live/pending orders.

Conclusion

ZeroMQ enables traders using any of its supported programming languages, to:

1. Create trading strategies outside MetaTrader
2. Use MetaTrader as the intermediary to market
3. Implement advanced trading techniques otherwise difficult (if not impossible) to implement in MetaTrader
4. Evaluate performance in much greater detail, e.g. by leveraging statistical techniques not available in MetaTrader
5. Leverage the Darwinex Analytical Toolkit to fine-tune investment-worthiness
6. .. and much more.

As always, we hope you’ve enjoyed this tutorial, and look forward to any feedback you may have for us.

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