onexit()

The onexit() function is used to handle the cleanup work of a strategy. Its maximum execution time is 5 minutes, and it must be implemented by the user.

Examples

• Test the onexit() function:

  • javascript
  • python
  • rust
  • cpp

  
      javascript
      
      
  function main(){
      Log("Starting, will stop after 5 seconds and execute cleanup function!")
      Sleep(1000 * 5)
  }
  
  // Implementation of the cleanup function
  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)
  

  
      rust
      
      
  fn main() {
      Log!("Starting, will stop after 5 seconds and execute cleanup function!");
      Sleep(1000 * 5);
  }
  
  // Implementation of the cleanup function
  fn onexit() {
      let beginTime = Unix() * 1000;
      loop {
          let nowTime = Unix() * 1000;
          Log!("Program stop countdown..cleanup started, elapsed time:", (nowTime - 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 a strategy in the backtesting system is usually designed as an infinite loop that continuously polls and executes, the onexit() function implemented by the strategy cannot be triggered in the backtesting system. You can trigger the execution of the onexit() function by detecting the backtesting system's end marker (the EOF exception).

  • javascript
  • python
  • rust
  • 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")
  

  
      rust
      
      
  fn onTick() {
      loop {
          match exchange.GetTicker(None) {
              Ok(ticker) => LogStatus!(_D(None), ticker.Last),
              Err(e) => {
                  // When the backtest ends, the API call returns Err; exit the loop so that main returns, thereby triggering the onexit() cleanup function
                  Log!("error:", e);
                  break;
              }
          }
          Sleep(500);
      }
  }
  
  fn main() {
      if exchange.GetName().starts_with("Futures_") {
          Log!("Exchange is futures");
          let _ = exchange.SetContractType("swap");
      } else {
          Log!("Exchange is spot");
      }
  
      onTick();
  }
  
  fn 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() is the initialization function implemented by the user. When a strategy starts running, the init() function is automatically executed first to complete the initialization tasks designed within 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!")

    rust
    
    
fn main() {
    Log!("First line of code executed!", "#FF0000");
    Log!("Exiting!");
}

// Initialization function
fn 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