在 GitHub 上也有报道： https ://github.com/Azure/azure-functions-durable-js/issues/86
使用 Azure Function Apps 的消费层时，服务进入空闲状态。对服务的下一个请求“唤醒”服务，并且可能需要一段时间才能响应（这是预期的）。
当服务“热”时，一切正常，但是，如果唤醒请求调用 Durable Functions 库中的 Orchestrator 函数，则 Orchestrator 会引发 Service Unavailable 错误：
Exception while executing function: Functions.HttpTrigger Result: Failure
Exception: Error: The service is unavailable.
Stack: Error: The service is unavailable.
at DurableOrchestrationClient.<anonymous> (D:\home\site\wwwroot\node_modules\durable-functions\lib\src\durableorchestrationclient.js:247:43)
at Generator.next (<anonymous>)
at fulfilled (D:\home\site\wwwroot\node_modules\durable-functions\lib\src\durableorchestrationclient.js:4:58)
at process._tickCallback (internal/process/next_tick.js:68:7)
堆栈跟踪：
Microsoft.Azure.WebJobs.Host.FunctionInvocationException:
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__19.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 321)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<TryExecuteAsyncCore>d__16.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 117)
Inner exception Microsoft.Azure.WebJobs.Script.Rpc.RpcException handled at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw:
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Script.Description.WorkerLanguageInvoker+<InvokeCore>d__6.MoveNext (Microsoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=nullMicrosoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null: C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\Rpc\WorkerLanguageInvoker.csMicrosoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null: 74)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Script.Description.FunctionInvokerBase+<Invoke>d__24.MoveNext (Microsoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=nullMicrosoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null: C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\FunctionInvokerBase.csMicrosoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null: 85)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Script.Description.FunctionGenerator+<Coerce>d__3`1.MoveNext (Microsoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=nullMicrosoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null: C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\FunctionGenerator.csMicrosoft.Azure.WebJobs.Script, Version=2.0.0.0, Culture=neutral, PublicKeyToken=null: 225)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Host.Executors.FunctionInvoker`2+<InvokeAsync>d__10.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionInvoker.csMicrosoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 52)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<InvokeAsync>d__27.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 584)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithWatchersAsync>d__26.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 531)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__25.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 467)
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at System.Runtime.CompilerServices.TaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__19.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.8.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 277)
我们遵循这种模式，使用 HTTP 触发器调用协调器函数： https ://docs.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-sequence
当服务“热”时，请求完美运行，功能按预期执行。如果调用编排器的 HTTP 请求是触发预热过程以使服务脱离空闲状态的请求，我们只会看到此错误。