Exception when specifying QUARKUS_OTEL_EXPORTER_OTLP_TRACES_PROTOCOL=grpc

[cuichenli]

Describe the bug

When using the environment variable QUARKUS_OTEL_EXPORTER_OTLP_TRACES_PROTOCOL=grpc Quarkus will throw exception

Caused by: java.lang.IllegalStateException: Only the GRPC Exporter is currently supported. Please check `otel.exporter.otlp.traces.protocol` property
	at io.quarkus.opentelemetry.runtime.exporter.otlp.OtlpRecorder.createOtlpGrpcSpanExporter(OtlpRecorder.java:110)
	at io.quarkus.opentelemetry.runtime.exporter.otlp.OtlpRecorder.installBatchSpanProcessorForOtlp(OtlpRecorder.java:61)

I think this issue has been resolved in #35156 for 3.3.0, but for the older version, this is still causing issues. Can we implement a fix for the older versions?

Looks like the logic at

quarkus/extensions/opentelemetry/runtime/src/main/java/io/quarkus/opentelemetry/runtime/exporter/otlp/OtlpRecorder.java

Line 109 in cca68dd

if (!exporterRuntimeConfig.traces().protocol().orElse("").equals(HTTP_PROTOBUF)) {

is a little bit wrong. Shouldn't the error be thrown when the protocol not equals to grpc instead?

Thanks! Please feel free to correct me if I am getting any thing wrong here.

Expected behavior

No exception should be thrown

Actual behavior

Exception thrown

How to Reproduce?

No response

Output of uname -a or ver

No response

Output of java -version

No response

GraalVM version (if different from Java)

No response

Quarkus version or git rev

3.2

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

No response

[quarkus-bot]

/cc @alesj (grpc), @brunobat (opentelemetry,tracing), @cescoffier (grpc), @radcortez (opentelemetry,tracing)

[brunobat]

cuichenli you mean: QUARKUS_OTEL_EXPORTER_OTLP_TRACES_PROTOCOL=http/protobuf, right?

[cuichenli]

nope, the value i set is QUARKUS_OTEL_EXPORTER_OTLP_TRACES_PROTOCOL=grpc

[brunobat]

Previously to Quarkus 3.3, with the previous exporter, there was only one protocol available. Setting that property has no effect.
Due to the piping rewiring, it would be very difficult to backport.

[cuichenli]

Sorry I may miss something here, but I thought to backport a fix we just need to update

 if (!exporterRuntimeConfig.traces().protocol().orElse("").equals(HTTP_PROTOBUF)) { 

to

 if (!exporterRuntimeConfig.traces().protocol().orElse("").equals(GRPC)) { 

The original code basically means if the protocol is set to grpc, then it does not equal to http/protobuf, hence one exception would be thrown.

Feel free to correct me if I am wrong.

[brunobat]

ok, it's just about the message, got it.
In the meantime, the workaround is not to set the property a all.

[siewp]

I would like to work on this simple issue :)

[brunobat]

@siewp go for it!

[brunobat]

fixed by #36166