As a dry run at taking an algo live, I took a (only very slightly modified) bootcamp solution and tried to launch it on to Alpaca paper trading. 
 

class OvernightBeatdown(QCAlgorithm): def Initialize(self): self.SetStartDate(2017, 11, 1) self.SetEndDate(2018, 7, 1) self.SetCash(100000) self.AddEquity("TSLA", Resolution.Minute) self.Schedule.On(self.DateRules.EveryDay(), self.TimeRules.BeforeMarketClose("TSLA", 0), self.ClosingBar) self.Schedule.On(self.DateRules.EveryDay(), self.TimeRules.AfterMarketOpen("TSLA", 1), self.OpeningBar) self.Schedule.On(self.DateRules.EveryDay(), self.TimeRules.AfterMarketOpen("TSLA", 45), self.ClosePositions) self.action = 0 self.window = RollingWindow[TradeBar](2) # Warmup for 5K bars ("periods") of your security resolution self.SetWarmUp(5000) #1. Create a manual Standard Deviation indicator to track recent volatility self.volatility = StandardDeviation("TSLA", 60) def OnData(self, data): if data["TSLA"] is not None: #2. Update our standard deviation indicator manually with algorithm time and TSLA's close price self.volatility.Update(self.Time, data["TSLA"].Close) def OpeningBar(self): if "TSLA" in self.CurrentSlice.Bars: self.window.Add(self.CurrentSlice["TSLA"]) #3. Use IsReady to check if both volatility and the window are ready, if not ready 'return' if not self.window.IsReady or not self.volatility.IsReady: return delta = self.window[0].Open - self.window[1].Close #4. Save an approximation of standard deviations to our deviations variable by dividing delta by the current volatility value: # Normally this is delta from the mean, but we'll approximate it with current value for this lesson. deviations = delta / self.volatility.Current.Value #5. SetHoldings to 100% TSLA if deviations is less than -3 standard deviations from the mean: if deviations < -3: self.SetHoldings("TSLA", 1) self.action = self.action + 1 self.Plot("Action", "Opertunity", self.action) self.Debug("Opening Price Collected") def ClosePositions(self): self.Liquidate() self.Debug("Holdings Liquidated") def ClosingBar(self): self.window.Add(self.CurrentSlice["TSLA"]) self.Debug("Closeing Price Collected")

It backtests fine, what when it goes live, I get this error at the first EOD:

 

at QuantConnect.Ex: tendedDictionary`1[T].get_Item (System.String ticker) [0x00020] in <4fc3bcd66016475d97c581dc9193f674>:0 at (wrapper manage: d-to-native) System.Reflection.MonoMethod.InternalInvoke(System.Reflection.MonoMethod,object,object[],System.Exception&) at System.Reflecti: on.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00032] in <b0e1ad7573a24fd5a9f2af9595e677e7>:0 2020-06-15 20:00:04 : Runtime Error: LiveTradingRealTimeHandler.Run(): There was an error in a scheduled event EveryDay: TSLA: 0 min before MarketClose. The error was KeyNotFoundException : 'TSLA' wasn't found in the Slice object, likely because there was no-data at this moment in time and it wasn't possible to fillforward historical data. Please check the data exists before accessing it with data.ContainsKey("TSLA") at QuantConnect.Da: ta.Slice.get_Item (QuantConnect.Symbol symbol) [0x00028] in <4fc3bcd66016475d97c581dc9193f674>:0 at QuantConnect.Ex: tendedDictionary`1[T].get_Item (System.String ticker) [0x00020] in <4fc3bcd66016475d97c581dc9193f674>:0 at (wrapper manage: d-to-native) System.Reflection.MonoMethod.InternalInvoke(System.Reflection.MonoMethod,object,object[],System.Exception&) at System.Reflecti: on.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00032] in <b0e1ad7573a24fd5a9f2af9595e677e7>:0 : StackTrace: System.Exception: LiveTradingRealTimeHandler.Run(): There was an error in a scheduled event EveryDay: TSLA: 0 min before MarketClose. The error was KeyNotFoundException : 'TSLA' wasn't found in the Slice object, likely because there was no-data at this moment in time and it wasn't possible to fillforward historical data. Please check the data exists before accessing it with data.ContainsKey("TSLA") at QuantConnect.Da: ta.Slice.get_Item (QuantConnect.Symbol symbol) [0x00028] in <4fc3bcd66016475d97c581dc9193f674>:0 at QuantConnect.Ex: tendedDictionary`1[T].get_Item (System.String ticker) [0x00020] in <4fc3bcd66016475d97c581dc9193f674>:0 at (wrapper manage: d-to-native) System.Reflection.MonoMethod.InternalInvoke(System.Reflection.MonoMethod,object,object[],System.Exception&) at System.Reflecti: on.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00032] in <b0e1ad7573a24fd5a9f2af9595e677e7>:0

Is there a different way that I should be acessing the price at the close of regular trading hours?