Orchestrator functions failing if not returning anything

[akshaykumars10]

We have an eternal orchestrator function in our durable function app. This orchestrator function doesn’t need to return anything. However, with the void return type, the orchestrator function is failing.

Error:
System.InvalidOperationException: The function invocation resulted in a null response. This means that either the orchestrator function was implemented incorrectly, the Durable Task language SDK was implemented incorrectly, or that the destination language worker is not sending the function result back to the host.

Function Code:

@FunctionName('EternalOrchestrator')
    public void startWorkflowSchedule(@DurableOrchestrationTrigger(name = 'ctx') TaskOrchestrationContext ctx) {

        LOGGER.info('Hello World');
        ctx.createTimer(Duration.ofSeconds(10)).await();
        ctx.continueAsNew(null);
    }

Function App Name: possmartpolling-java
Instance Id: testeternal123
Please let me know if any other details are required.

[cgillum]

Hi @akshaykumars10. I noticed that your host.json file references a "Preview" build of extension bundles v4.

  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle.Preview",
    "version": "[4.*, 5.0.0)"
  },

Do you encounter this same problem if you switch to using the non-preview (GA) version of the v4 extension bundles?

  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[4.*, 5.0.0)"
  },

[akshaykumars10]

Hi @cgillum
I am getting the same error with the non-preview (GA) version of the v4 extension bundles.
Here is the new instance id: testeternal1234

[cgillum]

Thanks @akshaykumars10 for confirming. A couple more questions to try and narrow down the problem further:

• Do you see this with other orchestrations or just with void + continueAsNew(null)?
• Do you see this problem if you change the function signature to return Object and then add return null immediately after your call to ctx.continueAsNew(null)?

[akshaykumars10]

Hi @cgillum

• If we have void then we are getting this error. Even this simple orchestrator without continueAsNewis also failing with the same error:

    @FunctionName("EternalOrchestrator")
    public void startWorkflowSchedule(@DurableOrchestrationTrigger(name = "ctx") TaskOrchestrationContext ctx) {
        LOGGER.info("Hello World");
        ctx.createTimer(Duration.ofSeconds(10)).await();
    }

• I tried changing the function signature to return Object and then added return null in the end.

@FunctionName("EternalOrchestrator")
    public Object startWorkflowSchedule(@DurableOrchestrationTrigger(name = "ctx") TaskOrchestrationContext ctx) {
        LOGGER.info("Hello World");
        ctx.createTimer(Duration.ofSeconds(10)).await();
        ctx.continueAsNew(null);
        return null;
    }

This fails with a different error. Error observed:
Exception: IllegalStateException: The orchestrator has already completed
We have an observation that in the case of eternalOrchestrator continueAsNew should be the last statement in the function. Otherwise, the statements that we have after the continueAsNew start executing. In this case because of return null our eternalOrchestrator is getting marked as completed in the first iteration itself.
We have a different github issue created for this bug: #118

[ChrisRomp]

Seeing this also even with some basic sample code adapted from the docs. I still get a 202 Accepted response with the usual method object properties like statusQueryGetUri. Calling the statusQueryGetUri shows "runtimeStatus": "Failed".

(Edited to remove java sleep in favor of ctx.createTimer() with same result.)

package com.function;

import com.microsoft.azure.functions.annotation.*;
import com.microsoft.azure.functions.*;

import java.time.Duration;

import com.microsoft.durabletask.*;
import com.microsoft.durabletask.azurefunctions.DurableClientContext;
import com.microsoft.durabletask.azurefunctions.DurableClientInput;
import com.microsoft.durabletask.azurefunctions.DurableOrchestrationTrigger;

public class EternalOrchTest {
    @FunctionName("Trigger_Eternal_Orchestration")
    public HttpResponseMessage triggerEternalOrchestration(
            @HttpTrigger(name = "req", methods = {HttpMethod.GET, HttpMethod.POST}, authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<?> req,
            @DurableClientInput(name = "durableContext") DurableClientContext durableContext) {

        String instanceID = "StaticID";
        DurableTaskClient client = durableContext.getClient();
        client.scheduleNewOrchestrationInstance("Periodic_Cleanup_Loop", null, instanceID);
        return durableContext.createCheckStatusResponse(req, instanceID);
    }

    @FunctionName("Periodic_Cleanup_Loop")
    public void periodicCleanupLoop(
            @DurableOrchestrationTrigger(name = "ctx") TaskOrchestrationContext ctx) {
        
        ctx.createTimer(Duration.ofHours(1)).await();
        ctx.continueAsNew(null);
    }
}

GET http://localhost:7071/api/Trigger_Eternal_Orchestration HTTP/1.1
User-Agent: vscode-restclient
accept-encoding: gzip, deflate

HTTP/1.1 202 Accepted
Connection: close
Content-Type: application/json; charset=utf-8
Date: Wed, 05 Apr 2023 21:34:52 GMT
Server: Kestrel
Location: http://localhost:7071/runtime/webhooks/durabletask/instances/StaticID?code={systemKey}
Transfer-Encoding: chunked

{
  "id": "StaticID",
  "purgeHistoryDeleteUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/StaticID?code={systemKey}",
  "sendEventPostUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/StaticID/raiseEvent/{eventName}?code={systemKey}",
  "statusQueryGetUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/StaticID?code={systemKey}",
  "terminatePostUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/StaticID/terminate?reason={text}&code={systemKey}"
}

Executing task: func host start 


Azure Functions Core Tools
Core Tools Version:       4.0.5095 Commit hash: N/A  (64-bit)
Function Runtime Version: 4.16.5.20396

[2023-04-05T21:34:44.184Z] Listening for transport dt_socket at address: 5005

Functions:

        Trigger_Eternal_Orchestration: [GET,POST] http://localhost:7071/api/Trigger_Eternal_Orchestration

        DoCleanup: activityTrigger

        Periodic_Cleanup_Loop: orchestrationTrigger

For detailed output, run func with --verbose flag.
[2023-04-05T21:34:45.204Z] Worker process started and initialized.
[2023-04-05T21:34:49.005Z] Host lock lease acquired by instance ID '0000000000000000000000006A2E027E'.
[2023-04-05T21:34:53.073Z] Executing 'Functions.Trigger_Eternal_Orchestration' (Reason='This function was programmatically called via the host APIs.', Id=6351548a-4fe3-42cf-b996-a0e7f4fc11a2)
[2023-04-05T21:34:53.770Z] Function "Trigger_Eternal_Orchestration" (Id: 6351548a-4fe3-42cf-b996-a0e7f4fc11a2) invoked by Java Worker
[2023-04-05T21:34:53.820Z] Executing 'Functions.Periodic_Cleanup_Loop' (Reason='(null)', Id=70a7b720-247b-43b1-b8fb-b0cfab96df57)
[2023-04-05T21:34:53.839Z] Executed 'Functions.Trigger_Eternal_Orchestration' (Succeeded, Id=6351548a-4fe3-42cf-b996-a0e7f4fc11a2, Duration=784ms)
[2023-04-05T21:34:53.867Z] Function "Periodic_Cleanup_Loop" (Id: 70a7b720-247b-43b1-b8fb-b0cfab96df57) invoked by Java Worker
[2023-04-05T21:34:53.884Z] Executed 'Functions.Periodic_Cleanup_Loop' (Failed, Id=70a7b720-247b-43b1-b8fb-b0cfab96df57, Duration=78ms)
[2023-04-05T21:34:53.884Z] System.Private.CoreLib: Exception while executing function: Functions.Periodic_Cleanup_Loop. Microsoft.Azure.WebJobs.Extensions.DurableTask: The function invocation resulted in a null response. This means that either the orchestrator function was implemented incorrectly, the Durable Task language SDK was implemented incorrectly, or that the destination language worker is not sending the function result back to the host.
[2023-04-05T21:34:53.887Z] StaticID: Function 'Periodic_Cleanup_Loop (Orchestrator)' failed with an error. Reason: Microsoft.Azure.WebJobs.Host.FunctionInvocationException: Exception while executing function: Functions.Periodic_Cleanup_Loop
[2023-04-05T21:34:53.887Z]  ---> System.InvalidOperationException: The function invocation resulted in a null response. This means that either the orchestrator function was implemented incorrectly, the Durable Task language SDK was implemented incorrectly, or that the destination language worker is not sending the function result back to the host.
[2023-04-05T21:34:53.887Z]    at Microsoft.Azure.WebJobs.Extensions.DurableTask.OutOfProcMiddleware.<>c__DisplayClass10_0.<<CallOrchestratorAsync>b__0>d.MoveNext() in D:\a\_work\1\s\src\WebJobs.Extensions.DurableTask\OutOfProcMiddleware.cs:line 127
[2023-04-05T21:34:53.887Z] --- End of stack trace from previous location ---
[2023-04-05T21:34:53.887Z]    at Microsoft.Azure.WebJobs.Host.Executors.TriggeredFunctionExecutor`1.<>c__DisplayClass7_0.<<TryExecuteAsync>b__0>d.MoveNext() in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\TriggeredFunctionExecutor.cs:line 50
[2023-04-05T21:34:53.888Z] --- End of stack trace from previous location ---
[2023-04-05T21:34:53.888Z]    at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.InvokeWithTimeoutAsync(IFunctionInvoker invoker, ParameterHelper parameterHelper, CancellationTokenSource timeoutTokenSource, CancellationTokenSource functionCancellationTokenSource, Boolean throwOnTimeout, TimeSpan timerInterval, IFunctionInstance instance) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:line 581
[2023-04-05T21:34:53.888Z]    at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithWatchersAsync(IFunctionInstanceEx instance, ParameterHelper parameterHelper, ILogger logger, CancellationTokenSource functionCancellationTokenSource) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:line 527
[2023-04-05T21:34:53.888Z]    at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithLoggingAsync(IFunctionInstanceEx instance, FunctionStartedMessage message, FunctionInstanceLogEntry instanceLogEntry, ParameterHelper parameterHelper, ILogger logger, CancellationToken cancellationToken) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:line 306
[2023-04-05T21:34:53.888Z]    --- End of inner exception stack trace ---
[2023-04-05T21:34:53.888Z]    at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithLoggingAsync(IFunctionInstanceEx instance, FunctionStartedMessage message, FunctionInstanceLogEntry instanceLogEntry, ParameterHelper parameterHelper, ILogger logger, CancellationToken cancellationToken) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:line 352
[2023-04-05T21:34:53.888Z]    at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.TryExecuteAsync(IFunctionInstance functionInstance, CancellationToken cancellationToken) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:line 108. IsReplay: False. State: Failed. HubName: JavaTestHub. AppName: . SlotName: . ExtensionVersion: 2.9.0. SequenceNumber: 4. TaskEventId: -1

[cgillum]

@kaibocai can you help find an owner for this item to help investigate? The problem seems to be that the orchestration middleware in the Java SDK is not returning a value back to the Durable Functions extension. That's basically what this error message means:

System.InvalidOperationException: The function invocation resulted in a null response. This means that either the orchestrator function was implemented incorrectly, the Durable Task language SDK was implemented incorrectly, or that the destination language worker is not sending the function result back to the host.