Make Micrometer optional

[ttddyy]

One of the team I work with have an application that does not use micrometer.

In configurations, there are places referencing WavefrontConfig from micrometer.
(here, here - this one may relate to #74 )

For opentracing, they seems to be retrieving source from WavefrontConfig.

Probably, it could be replaced with a supplier bean like this:

@FunctionalInterface
public interface WavefrontSourceProvider {

	String getSource();

}

Then, conditionally create one to use WavefrontConfig if micrometer is available.

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(WavefrontConfig.class)
@ConditionalOnMissingBean(WavefrontSourceProvider.class)
static class MicrometerSourceConfiguration {

	@Bean
	WavefrontSourceProvider wavefrontSourceProvider(WavefrontConfig wavefrontConfig) {
		return wavefrontConfig::source;
	}

}

I didn't check other places, but would be nice to make the micrometer optional.

[snicoll]

I don't really understand what you mean by "not using micrometer". Do you mean not using metrics? This a starter for Spring Boot and micrometer is a core (i.e. non optional) for metrics.

[sushantdewan123]

As Stephane mentioned above, we would like to make the scope of metrics/micrometer as non-optional. Closing this as wont fix.