management.metrics.export.tags-as-prefix property seems not to be honored in Spring Boot 2.0.0.RELEASE

[jceloi]

Greetings,

I'm currently migrating a 1.5.X Spring Boot project to 2.0.0.RELEASE and did struggle a bit on the metrics to micrometer side.

It seems to me that #12262 is still relevant.
I have to manually override the HierarchicalNameMapper to a GraphiteHierarchicalNameMapper so as to use the tags as prefix feature (tested and working).

    @Bean
    public HierarchicalNameMapper hierarchicalNameMapper() {
        return new GraphiteHierarchicalNameMapper("myTag");
    }

The HierarchicalNameMapper.DEFAULT.toHierarchicalName() does not use this property at all and is in my case used by default.

It is as if there was some missing autoconfiguration somewhere that would not use the correct name mapper in a Graphite context.

As a result the management.metrics.export.graphite.tags-as-prefix property seems totally useless by default in my context, which is a Graphite context. I can see that it is correctly valued in the MeterRegistry's config and such, but as the DEFAULT Name Mapper is used, it's to no avail.

[jceloi]

Looking at GraphiteMetricsExportAutoConfiguration and the matched /condition in my app

	@Bean
	@ConditionalOnMissingBean
	public HierarchicalNameMapper hierarchicalNameMapper() {
		return HierarchicalNameMapper.DEFAULT;
	}

I think that the default Name Mapper should be logically a GraphiteHierarchicalNameMapper to use the specificity of that property.

[wilkinsona]

I think that the default Name Mapper should be logically a GraphiteHierarchicalNameMapper to use the specificity of that property.

That certainly sounds logical, although Micrometer's doing the same thing as Boot in its Spring Boot 1.5 support.

@jkschneider Is this a bug in both codebases?

[ielfatmi]

I think that GraphiteMeterRegistry bean instantiation in GraphiteMetricsExportAutoConfiguration should be reviewed to get something like this :

@Bean
@ConditionalOnMissingBean
public GraphiteMeterRegistry graphiteMeterRegistry(GraphiteConfig graphiteConfig, Clock clock) {
  return new GraphiteMeterRegistry(graphiteConfig, clock);
}

Since GraphiteMeterRegistry(GraphiteConfig config, Clock clock) constructor is using GraphiteHierarchicalNameMapper as HierarchicalNameMapper.

[jkschneider]

It appears to me you are simply missing a word in the property?

management.metrics.export.graphite.tags-as-prefix instead of
management.metrics.export.tags-as-prefix

[jceloi]

Hello @jkschneider ,

I don't think so, I was quoting the full property name in my first post and as I said, I can see while debugging the MeterRegistry that that specific configuration value is correctly read.

The underlying problem is that - according to me - the DEFAULT HierarchicalNameMapper just doesn't use that prop, and that it is the default instance created in the GraphiteMetricsExportAutoConfiguration .

[jkschneider]

Ah, sorry @jceloi. Thanks for the detailed report.