Expose S3 Request Metrics

[azkrishpy]

Issue #, if available:
#806
Description of changes:
Exposes S3 Request Metrics from the CRT S3 Client.

• S3RequestMetrics: Captures timing, request/response info, and error details for each S3 request attempt
• onTelemetry() callback: New method in S3MetaRequestResponseHandler invoked after each request completes
• ErrorType classification: Categorizes errors (SUCCESS, THROTTLING, SERVER_ERROR, CONFIGURED_TIMEOUT, IO, OTHER)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[TingDaoK]

I'll vote for a generic API in the exception class. And replace the isErrorRetryable in HTTP as well

[azkrishpy]

Java SDK users can use a custom MetricPublisher that bridges CRT metrics to SDK's MetricCollection:

public class CrtMetricPublisher implements MetricPublisher {
    private final MetricPublisher delegate;

    public CrtMetricPublisher(MetricPublisher delegate) {
        this.delegate = delegate;
    }

    public void publishCrtMetrics(S3RequestMetrics crtMetrics) {
        MetricCollection collection = MetricCollection.builder()
            .name("S3Request")
            .creationTime(Instant.now())
            .putMetric(CoreMetric.API_CALL_DURATION, 
                Duration.ofNanos(crtMetrics.getApiCallDurationNs()))
            .putMetric(CoreMetric.SERVICE_ID, crtMetrics.getServiceId())
            .putMetric(CoreMetric.OPERATION_NAME, crtMetrics.getOperationName())
            .putMetric(CoreMetric.RETRY_COUNT, crtMetrics.getRetryCount())
            .putMetric(CoreMetric.AWS_REQUEST_ID, crtMetrics.getAwsRequestId())
            .putMetric(CoreMetric.AWS_EXTENDED_REQUEST_ID, crtMetrics.getAwsExtendedRequestId())
            .putMetric(CoreMetric.BACKOFF_DELAY_DURATION, 
                Duration.ofNanos(crtMetrics.getBackoffDelayDurationNs()))
            .putMetric(CoreMetric.SERVICE_CALL_DURATION, 
                Duration.ofNanos(crtMetrics.getServiceCallDurationNs()))
            .putMetric(CoreMetric.SIGNING_DURATION, 
                Duration.ofNanos(crtMetrics.getSigningDurationNs()))
            .build();

        delegate.publish(collection);
    }

    @Override
    public void publish(MetricCollection metricCollection) {
        delegate.publish(metricCollection);
    }

    @Override
    public void close() {
        delegate.close();
    }
}

Usage

CrtMetricPublisher metricPublisher = new CrtMetricPublisher(
    LoggingMetricPublisher.create());

S3MetaRequestResponseHandler responseHandler = new S3MetaRequestResponseHandler() {
    @Override
    public void onTelemetry(S3RequestMetrics metrics) {
        metricPublisher.publishCrtMetrics(metrics);
    }

    @Override
    public void onFinished(S3FinishedResponseContext context) {
        // Handle completion
    }
};

S3MetaRequestOptions options = new S3MetaRequestOptions()
    .withMetaRequestType(MetaRequestType.GET_OBJECT)
    .withHttpRequest(httpRequest)
    .withResponseHandler(responseHandler);

try (S3MetaRequest request = client.makeMetaRequest(options)) {
    // Request executes, metrics published via onTelemetry callback
}

[azkrishpy]

The following metrics are not available from CRT for java since sdk has the information:

• CredentialsFetchDuration
• EndpointResolveDuration
• MarshallingDuration
• ServiceEndpoint