onexit()

onexit() is implemented by the user to clean up when the strategy exits; it is optional. It may run for at most 5 minutes and is terminated when it exceeds that. For when each language calls onexit(), see Writing Strategies → Strategy Structure.

Examples

• Testing the onexit() function:

  • javascript
  • python
  • rust

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

• In the backtesting system a strategy is usually an endless polling loop, so main() has not returned normally when the backtest data ends, and JavaScript and Python strategies therefore do not run onexit(). In a backtest (IsVirtual() is true) you can catch the exception (EOF) thrown when the backtest ends so that main() returns and onexit() runs. In Rust the API calls return Err when the backtest ends, so just leave the loop.

  • javascript
  • python
  • rust

  
      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) => {
                  // API calls return Err when the backtest ends; leaving the loop lets main return, which triggers onexit()
                  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");
  }