Error when use google pubsub emulator and Spring function.adapter.gcp.GcfJarLauncher

Question

I am trying to make a GCP Cloud function trigger by pubsub message using Spring Cloud framework. I have started with the example provided by Spring team which is quite simple.

But when I execute the command

`curl 127.0.1:8080 -H "Content-Type: application/json" -d '{"data":"aGVsbG8="}'`

I get

`AVERTISSEMENT: Failed to execute org.springframework.cloud.function.adapter.gcp.GcfJarLauncher
java.lang.ClassCastException: org.eclipse.jetty.server.Request$1 incompatible with com.example.PubSubMessage
    at com.example.BackgroundFunctionMain$$Lambda$349/0x0000000015b164b8.accept(Unknown Source)
    at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.invokeConsumer(SimpleFunctionRegistry.java:969)
    at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.doApply(SimpleFunctionRegistry.java:698)
    at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.apply(SimpleFunctionRegistry.java:544)
    at org.springframework.cloud.function.adapter.gcp.FunctionInvoker.service(FunctionInvoker.java:98)`

Also, when I try to to get message from PUBSUB emulator with push subscription, I get

`AVERTISSEMENT: Failed to execute org.springframework.cloud.function.adapter.gcp.GcfJarLauncher
java.lang.NullPointerException: Cannot invoke "java.lang.String.getBytes(java.nio.charset.Charset)" because "src" is null
    at java.base/java.util.Base64$Decoder.decode(Base64.java:589)
    at com.example.BackgroundFunctionMain.lambda$pubSubFunction$0(BackgroundFunctionMain.java:27)
    at com.example.BackgroundFunctionMain$$Lambda$349/0x0000000072a4b6a8.accept(Unknown Source)
    at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.invokeConsumer(SimpleFunctionRegistry.java:969)`

But, I when I post data from POSTMAN or from git bash windows with curl command it's working fine.

I have try to set code page chcp 65001 to change windows cmd.exe to UTF-8 but without any sucess.

By the way, the pubsub emulator is working fine when I read message using google backgroudn function like

 ` @Override
  public void accept(PubSubMessage pubSubMessage, Context context) {
    log.info("Received message with id " + context.eventId());
    String message = null;
    if (pubSubMessage != null && pubSubMessage.getData() != null) {
      message =
          new String(
              Base64.getDecoder().decode(pubSubMessage.getData().getBytes(StandardCharsets.UTF_8)),
              StandardCharsets.UTF_8);
    }

`

What do I need to change to make the emulator working with Spring cloud?

I have many messages to implements and test publish/subcription on local with emulator, I would like to avoid to use POSTMAN and base64 manual conversion for integration testing.

Answer 1

Currently Spring-cloud-function is not working on local with Google PubSub emulator.

Issue has been raised here