Add JVM metrics to auto-publish to prometheus registry

[collado-mike]

Description

Micrometer contains a host of JVM metrics we should be publishing via Prometheus. This adds several of the default metrics.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• Documentation update
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

gradle runApp with the following curl command/output:

$ curl http://localhost:8182/metrics
# HELP jvm_buffer_count_buffers An estimate of the number of buffers in the pool
# TYPE jvm_buffer_count_buffers gauge
jvm_buffer_count_buffers{id="direct"} 1.0
jvm_buffer_count_buffers{id="mapped"} 0.0
jvm_buffer_count_buffers{id="mapped - 'non-volatile memory'"} 0.0
# HELP jvm_buffer_memory_used_bytes An estimate of the memory that the Java virtual machine is using for this buffer pool
# TYPE jvm_buffer_memory_used_bytes gauge
jvm_buffer_memory_used_bytes{id="direct"} 8192.0
jvm_buffer_memory_used_bytes{id="mapped"} 0.0
jvm_buffer_memory_used_bytes{id="mapped - 'non-volatile memory'"} 0.0
# HELP jvm_buffer_total_capacity_bytes An estimate of the total capacity of the buffers in this pool
# TYPE jvm_buffer_total_capacity_bytes gauge
jvm_buffer_total_capacity_bytes{id="direct"} 8192.0
jvm_buffer_total_capacity_bytes{id="mapped"} 0.0
jvm_buffer_total_capacity_bytes{id="mapped - 'non-volatile memory'"} 0.0
# HELP jvm_classes_loaded_classes The number of classes that are currently loaded in the Java virtual machine
# TYPE jvm_classes_loaded_classes gauge
jvm_classes_loaded_classes 8138.0
# HELP jvm_classes_unloaded_classes_total The total number of classes unloaded since the Java virtual machine has started execution
# TYPE jvm_classes_unloaded_classes_total counter
jvm_classes_unloaded_classes_total 0.0
# HELP jvm_gc_live_data_size_bytes Size of long-lived heap memory pool after reclamation
# TYPE jvm_gc_live_data_size_bytes gauge
jvm_gc_live_data_size_bytes 0.0

• Test A
• Test B

Test Configuration:

• Hardware:
• Toolchain:
• SDK:

Checklist:

Please delete options that are not relevant.

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• If adding new functionality, I have discussed my implementation with the community using the linked GitHub issue

[eric-maynard]

style

[collado-mike]

yeah, the google formatter is already yelling at me 😅

[eric-maynard]

One comment on style, but otherwise this seems reasonable to me.

I wonder if we should make this configurable

[collado-mike]

I wonder if we should make this configurable

Adding support for other configurable publishers makes sense, but I think we can keep that separate from this PR.