Add billing event logging for embedding and reranking token usage

[Hazel-Datastax]

What this PR does:
Add billing event logging for embedding and reranking token usage.

Event definition: https://github.com/riptano/cloud-billing/blob/vectorize-usage-design/docs/usage-event-design/vectorize-usage-events.md

Sample logs:

{"id":"f6716d5a-7ca4-4afa-9826-a14561b8c0b7","timestamp":"2026-05-22T00:43:30.549312Z","product":"serverless","event_type":"nvidia_embeddings_tokens","properties":{"usage":7,"region":"CASSANDRA_REGION","resource_type":"serverless_database","resource_id":"SINGLE-TENANT"}}
{"id":"aede7d63-eb64-4c86-9dc3-a8432c07f120","timestamp":"2026-05-22T00:43:30.549335Z","product":"serverless","event_type":"nvidia_egress_bytes","properties":{"usage":84,"region":"CASSANDRA_REGION","resource_type":"serverless_database","resource_id":"SINGLE-TENANT"}}
{"id":"98cb204d-8f8b-4784-aab6-0b7e96b9695d","timestamp":"2026-05-22T00:43:30.549339Z","product":"serverless","event_type":"nvidia_gpu_plane_egress_bytes","properties":{"usage":21832,"region":"CASSANDRA_REGION","resource_type":"serverless_database","resource_id":"SINGLE-TENANT"}}

Which issue(s) this PR fixes:
Fixes #2137

Checklist

• Changes manually tested
• Automated Tests added/updated
• Documentation added/updated
• CLA Signed: DataStax CLA

[github-actions]

📈 Unit Test Coverage Delta vs Main Branch

Metric	Value
Main Branch	51.67%
This PR	51.79%
Delta	🟢 +0.11%
✅ Coverage improved!

[github-actions]

Unit Test Coverage Report

Overall Project	51.79% -0.14%	🍏
Files changed	67.39%	🍏

File	Coverage
TenantFactory.java	100%	🍏
MeteredEmbeddingProviderWrapper.java	97.57%	🍏
Tenant.java	93.62%	🍏
ApiFeature.java	90.43%	🍏
FindAndRerankOperationBuilder.java	82.16%	🍏
Billing.java	81.33% -18.67%	🍏
ModelType.java	74.55% -1.82%	🍏
BillingEvent.java	61.32% -38.68%	🍏
RerankingTask.java	7.64% -3.89%	❌
FindAndRerankCommandResolver.java	0% -27.66%	❌
DataVectorizerService.java	0% -1.86%	❌
SubdomainTenantResolver.java	0% -27.18%	❌

[github-actions]

📉 Integration Test Coverage Delta vs Main Branch (dse69-it)

Metric	Value
Main Branch	72.77%
This PR	72.59%
Delta	🔴 -0.17%
⚠️ Coverage decreased

[github-actions]

Integration Test Coverage Report (dse69-it)

Overall Project	72.59% -0.32%	🍏
Files changed	28.26%	❌

File	Coverage
FindAndRerankCommandResolver.java	100%	🍏
MeteredEmbeddingProviderWrapper.java	97.22%	🍏
ApiFeature.java	90.43%	🍏
FindAndRerankOperationBuilder.java	84.86%	🍏
TenantFactory.java	72.34%	🍏
RerankingTask.java	59.17% -2.5%	❌
Tenant.java	45.39% -35.46%	❌
ModelType.java	38.18% -16.36%	❌
DataVectorizerService.java	23.7%	🍏
Billing.java	22.22% -77.78%	❌
BillingEvent.java	0%	❌
SubdomainTenantResolver.java	0% -27.18%	❌

[github-actions]

📉 Integration Test Coverage Delta vs Main Branch (hcd-it)

Metric	Value
Main Branch	74.19%
This PR	74.01%
Delta	🔴 -0.18%
⚠️ Coverage decreased

[github-actions]

Integration Test Coverage Report (hcd-it)

Overall Project	74.01% -0.32%	🍏
Files changed	28.26%	❌

File	Coverage
FindAndRerankCommandResolver.java	100%	🍏
MeteredEmbeddingProviderWrapper.java	97.22%	🍏
FindAndRerankOperationBuilder.java	90.68%	🍏
ApiFeature.java	90.43%	🍏
TenantFactory.java	72.34%	🍏
RerankingTask.java	59.17% -2.5%	❌
Tenant.java	45.39% -35.46%	❌
ModelType.java	38.18% -16.36%	❌
DataVectorizerService.java	23.7%	🍏
Billing.java	22.22% -77.78%	❌
BillingEvent.java	0%	❌
SubdomainTenantResolver.java	0% -27.18%	❌

[tatu-at-datastax]

Looks good, some thoughts added.

[amorton]

some tweaks as discussed, heading in the right direction

[amorton]

for info, maybe make a change. Below is an example of setting a logger category to use a different appender / handler

PLAIN_CONSOLE - defines a new appender / handler that will write using a different format. It is a handler of type console , named PLAIN_CONSOLE, with a different formatt than the default handler called "console"

NOTE: we will want to check with billing peeps what format they want.

this %c %m$n from your code would log

billing.event {"the": json"}

take away %c to just log the json on a line by itself.

the category: io.stargate.sgv2.jsonapi.testbench.reporting.TestBenchConsoleWriter says for this named logger, its level is INFO and it would use the PLAIN_CONSOLE appender / handler, AND importantly DO NOT inherit from above - so do not also use the console appender

 log:
    console:
      format: "%-5p [%t] %d{yyyy-MM-dd HH:mm:ss,SSS} %F:%L - %m%n"
    handler:
      console:
        PLAIN_CONSOLE:
          format: "%m%n"
    category:
      # production log level for this category is DEBUG, way too noisy for tests
      'io.stargate':
      # Fine for JVM mode; if building native images, use index-dependency instead
      'io.quarkus.deployment.steps.ReflectiveHierarchyStep':
        level: ERROR
      'io.stargate.sgv2.jsonapi.testbench.reporting.TestBenchConsoleWriter':
        level: INFO
        handlers:
          - PLAIN_CONSOLE
        use-parent-handlers: false

[amorton]

hit wrong button, tweaks as discussed

[tatu-at-datastax]

I think issue for this is #2137 fwtw.