onexit()

onexit() function is used to handle cleanup operations when the strategy exits, with a maximum execution time of 5 minutes, and needs to be implemented by the user.

Examples

• Test the onexit() function:

  • javascript
  • python
  • cpp

  
      javascript
      
      
  function main(){
      Log("Starting, will stop after 5 seconds and execute cleanup function!")
      Sleep(1000 * 5)
  }
  
  // Cleanup function implementation
  function onexit(){
      var beginTime = new Date().getTime()
      while(true){
          var nowTime = new Date().getTime()
          Log("Program stop countdown..cleanup started, elapsed time:", (nowTime - beginTime) / 1000, "seconds!")
          Sleep(1000)
      }
  }
  

  
      python
      
      
  import time
  def main():
      Log("Starting, will stop after 5 seconds and execute cleanup function!")
      Sleep(1000 * 5)
  
  def onexit():
      beginTime = time.time() * 1000
      while True:
          ts = time.time() * 1000
          Log("Program stop countdown..cleanup started, elapsed time:", (ts - beginTime) / 1000, "seconds!")
          Sleep(1000)
  

  
      c++
      
      
  void main() {
      Log("Starting, will stop after 5 seconds and execute cleanup function!");
      Sleep(1000 * 5);
  }
  
  void onexit() {
      auto beginTime = Unix() * 1000;
      while(true) {
          auto ts = Unix() * 1000;
          Log("Program stop countdown..cleanup started, elapsed time:", (ts - beginTime) / 1000, "seconds!");
          Sleep(1000);
      }
  }
  

• Since strategies in the backtesting system are typically designed to run in an infinite loop with continuous polling execution, the backtesting system cannot trigger the onexit() function implemented in the strategy. The execution of the onexit() function can be triggered by detecting the backtesting system's end marker (EOF exception).

  • javascript
  • python
  • cpp

  
      javascript
      
      
  function main() {
      if (exchange.GetName().startsWith("Futures_")) {
          Log("Exchange is futures")
          exchange.SetContractType("swap")
      } else {
          Log("Exchange is spot")
      }
  
      if (IsVirtual()) {
          try {
              onTick()
          } catch (e) {
              Log("error:", e)
          }
      } else {
          onTick()
      }
  }
  
  function onTick() {
      while (true) {
          var ticker = exchange.GetTicker()
          LogStatus(_D(), ticker ? ticker.Last : "--")
          Sleep(500)
      }
  }
  
  function onexit() {
      Log("Executing cleanup function")
  }
  

  
      python
      
      
  def main():
      if exchange.GetName().startswith("Futures_"):
          Log("Exchange is futures")
      else:
          Log("Exchange is spot")
  
      if IsVirtual():
          try:
              onTick()
          except Exception as e:
              Log(e)
      else:
          onTick()
  
  def onTick():
      while True:
          ticker = exchange.GetTicker()
          LogStatus(_D(), ticker["Last"] if ticker else "--")
          Sleep(500)
  
  def onexit():
      Log("Executing cleanup function")
  

  
      c++
      
      
  #include <iostream>
  #include <exception>
  #include <string>
  
  void onTick() {
      while (true) {
          auto ticker = exchange.GetTicker();
          LogStatus(_D(), ticker);
          Sleep(500);
      }
  }
  
  void main() {
      std::string prefix = "Futures_";
      bool startsWith = exchange.GetName().substr(0, prefix.length()) == prefix;
      if (startsWith) {
          Log("Exchange is futures");
          exchange.SetContractType("swap");
      } else {
          Log("Exchange is spot");
      }
  
      if (IsVirtual()) {
          try {
              onTick();
          } catch (...) {
              std::cerr << "Caught unknown exception" << std::endl;
          }
      } else {
          onTick();
      }
  }
  
  void onexit() {
      Log("Executing cleanup function");
  }
  

init()

init(), user-implemented initialization function init(), which will be automatically executed first when the strategy starts running, used to complete initialization tasks designed in the strategy.

Examples

    javascript
    
    
function main(){
    Log("First line of code executed!", "#FF0000")
    Log("Exiting!")
}

// Initialization function
function init(){
    Log("Initializing!")
}

    python
    
    
def main():
    Log("First line of code executed!", "#FF0000")
    Log("Exiting!")

def init():
    Log("Initializing!")

    c++
    
    
void main() {
    Log("First line of code executed!", "#FF0000");
    Log("Exiting!");
}

void init() {
    Log("Initializing!");
}

onerror()

onerror(), triggered when an exception occurs, the onerror() function will be executed. This function is not supported in Python and C++ language strategies. The onerror() function can accept a msg parameter, which contains the error message when the exception is triggered.

Examples

    javascript
    
    
function main() {
    var arr = []
    Log(arr[6].Close)  // Intentionally trigger a program exception here
}

function onerror(msg) {
    Log("Error:", msg)
}

    python
    
    
# Python not supported

    c++
    
    
// C++ not supported