By adding the context concept, we can now include HTTP metrics in observe::MetricsLayer. In general, we have full access to HttpFetch, allowing us to wrap our own logic around it. Based on this, we can add metrics for HTTP request duration in seconds and track the number of bytes sent.

My current plan is to add the following metrics:

• http_request_duration_seconds: Histogram of time spent during http requests
• http_request_bytes: Histogram of the bytes transferred during http requests

Available labels includes scheme, namespace, root, operation

We will need to implement the following new methods for different metrics layers:

/// Observe the http request duration in seconds.
fn observe_http_request_duration_seconds(
    &self,
    info: Arc<AccessorInfo>,
    op: Operation,
    duration: Duration,
) {
    let _ = (info, op, duration);
}

/// Observe the operation bytes happened in http request like read and write.
fn observe_http_request_bytes(&self, info: Arc<AccessorInfo>, op: Operation, bytes: usize) {
    let _ = (info, op, bytes);
}

Refer to the OtelMetricsLayer as an example: #5800

Metrics

• http request metrics: feat(core): Implement http related metrics support for prom client #5798

Update Layers for http request metrics

• PrometheusLayer: feat(core/layers): implement http related metrics support for prometheus #5847
• PrometheusClientLayer: feat(core): Implement http related metrics support for prom client #5798
• OtelMetricsLayer: feat(core): Implement http related metrics support for otel #5800
• MetricsLayer: feat(core/layers): implement http related metrics support for metrics #5848