Rust SDK is missing metrics API

[yskopets]

No description provided.

[czh-123-rust]

• hello @PiotrSikora , when I use metric's interface to test prometheus function, I found that the return value of get_metric() is alway 0. And prometheus can not receive the metric counter data normally. The code is shown below.

lazy_static! {
static ref SCP_REQ_METRIC_ID: Mutex =
Mutex::new(define_metric(MetricType::Counter, "http_request").unwrap());
}
pub fn get_metric_id() -> u32 {
let scp_req_metric_id = SCP_REQ_METRIC_ID.lock().unwrap();
*scp_req_metric_id
}

impl HttpContext for Limiter {
fn on_http_request_headers(&mut self, _: usize) -> Action {
info!("=====on_http_request_headers=====");
increment_metric(get_metric_id(), 1).unwrap();
info!("---new metric_id={:?}", get_metric_id());
let get_return_value = get_metric(get_metric_id()).unwrap();
info!("---get_return_value={:?}", get_return_value);
......
......

• Out put information:
  wasm log rate-limit.default rate_limit_handle: =====on_http_request_headers=====
  wasm log rate-limit.default rate_limit_handle: ---new metric_id=4
  wasm log rate-limit.default rate_limit_handle: ---get metric ok, return_value=0
  wasm log rate-limit.default rate_limit_handle: ---get_return_value=0