NullPointerException in MicrometerRecorder.registerMetrics

[rolfborst]

Describe the bug

Hello Quarkus-Team,

great work. I'm currently moving a project from tomee to quarkus. This is a example project for my students in "database technology". So I have used a lot of your extensions for jpa, mongodb, neo4j, cassandra, ... All worked absolutly fine. In a last step I want to introduce the extension "quarkus-micrometer-registry-prometheus" to demonstrate the use of prometheus as a time series database. When I add this extension, the project doesn't start any more. The exception is:

2021-09-23 08:55:32,209 ERROR [io.qua.run.Application] (Quarkus Main Thread) Failed to start application (with profile dev): java.lang.NullPointerException
	at io.quarkus.micrometer.runtime.MicrometerRecorder.registerMetrics(MicrometerRecorder.java:169)
	at io.quarkus.deployment.steps.MicrometerProcessor$configureRegistry-2125003310.deploy_0(MicrometerProcessor$configureRegistry-2125003310.zig:123)
	at io.quarkus.deployment.steps.MicrometerProcessor$configureRegistry-2125003310.deploy(MicrometerProcessor$configureRegistry-2125003310.zig:40)
	at io.quarkus.runner.ApplicationImpl.doStart(ApplicationImpl.zig:1189)
	at io.quarkus.runtime.Application.start(Application.java:101)
	at io.quarkus.runtime.ApplicationLifecycleManager.run(ApplicationLifecycleManager.java:101)

It seems to me, that one of my lot of extension does not work correctly and so corrupt the complete system.

Is it possible, that you do a null check in the registerMetrics method (the parameter consumer is called with null)?

    public void registerMetrics(Consumer<MetricsFactory> consumer) {
        consumer.accept(factory);
    }

I do a greater google search but it seems that no other people has my problem ;-)

I have tried to deactivate all of the metrics in the application.properties to find the "corrupt" extension but no of these deactivations have an effect to my NullPointerProblem.

quarkus.micrometer.binder.jvm=false
quarkus.micrometer.binder.system=false
quarkus.micrometer.binder-enabled-default=false
quarkus.micrometer.registry-enabled-default=false
quarkus.scheduler.metrics.enabled=false
quarkus.datasource.jdbc.enable-metrics=false
quarkus.datasource.metrics.enabled=false
quarkus.hibernate-orm.statistics=false
quarkus.hibernate-orm.metrics.enabled=false
quarkus.neo4j.pool.metrics.enabled=false
quarkus.log.metrics.enabled=false
quarkus.smallrye-graphql.metrics.enabled=false
quarkus.grpc.metrics.enabled=false

Only when I deactivate all with "quarkus.micrometer.enabled=true" there is no NullPointerException any more. But then I also have no metrics ;-)

For me, this is not a serious problem, because that is a project for students, but I want to report the problem so that you can think about a null check at this point.

Bye
Rolf

Expected behavior

No response

Actual behavior

No response

How to Reproduce?

No response

Output of uname -a or ver

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Output of java -version

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GraalVM version (if different from Java)

No response

Quarkus version or git rev

2.1.0.Final

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

No response

Additional information

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[quarkus-bot]

/cc @ebullient, @jmartisk, @kenfinnigan

[geoand]

It looks like neo4j is the one responsible for the null consumer: https://github.com/quarkusio/quarkus/blob/2.3.0.CR1/extensions/neo4j/runtime/src/main/java/io/quarkus/neo4j/runtime/Neo4jDriverRecorder.java#L79

I'll leave it up to @ebullient to decide whether null should be allowed (and therefore guarded against) or not.

[rolfborst]

Wow, absolutly great work how fast you find the problem :-)

When I activate the neo4j-metrics all works fine:

quarkus.neo4j.pool.metrics.enabled=true

When I set it to false or leave it unset, I get the NullPointerException

[ebullient]

I should absolutely be checking for null because it can apparently happen, though it would be kinder for neo4j not to register the supplier at all unless metrics are turned on. I'll try to fix both. Thanks for looking Georgios.. you beat me to it.

[geoand]

👍🏼