Cosmos: Allowing sampling for diagnostics

[FabianMeiswinkel]

Description

This PR allows applying sampling for diagnostic capturing in the Cosmos DB SDK. The motivation for adding this capability is to allow tuning the client-side resource consumption overhead that applications allow for diagnostics. Depending on the workload the PCU overhead when enabling diagnostics can be around 15-20 percent - in many workloads it will be significantly lower - but especially for very point-read heavy workloads it can be around 15%. The sampling rate can be modified after Cosmos Client initialization - so the sampling rate can be modified without any restarts being necessary.

CosmosClientTelemetryConfig clientTelemetryCfg = new CosmosClientTelemetryConfig()
    .diagnosticsHandler(CosmosDiagnosticsHandler.DEFAULT_LOGGING_HANDLER)
    .metricsOptions(new CosmosMicrometerMetricsOptions().meterRegistry(meterRegistry));

CosmosClientBuilder builder = this
    .getClientBuilder()
    .clientTelemetryConfig(clientTelemetryCfg);

CosmosContainer container = this.getContainer(builder);
executeTestCase(container);

meterRegistry.clear();
meterRegistry.close();

Set sampling rate to 25%

// change sample rate to 25%
clientTelemetryCfg.sampleDiagnostics(0.25);
executeTestCase(container);

Reduce sample rate to 0 - disable all diagnostics

// reduce sample rate to 0 - disable all diagnostics
clientTelemetryCfg.sampleDiagnostics(0);
executeTestCase(container);

set sample rate to 1 - enable all diagnostics (no sampling anymore)

// set sample rate to 1 - enable all diagnostics (no sampling anymore)
clientTelemetryCfg.sampleDiagnostics(1);
executeTestCase(container);

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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• Title of the pull request is clear and informative.
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Testing Guidelines

• Pull request includes test coverage for the included changes.

[azure-sdk]

API change check

APIView has identified API level changes in this PR and created following API reviews.

azure-cosmos

[kushagraThapar]

LGTM, one concern on the usage of ThreadLocalRandom

[xinlian12]

LGTM, thanks

[FabianMeiswinkel]

/check-enforcer override

[FabianMeiswinkel]

Failures are known issues in CI pipeline - overriding status checks

[FabianMeiswinkel]

/check-enforcer override