Trait MetricsCallbackProvider 

pub trait MetricsCallbackProvider:
    Send
    + Sync
    + Clone
    + 'static {
    // Required methods
    fn on_request(&self, path: String);
    fn on_response(
        &self,
        path: String,
        latency: Duration,
        status: u16,
        grpc_status_code: Code,
    );

    // Provided methods
    fn on_error(&self, _latency: Duration, _grpc_status_code: Code) { ... }
    fn on_start(&self, _path: &str) { ... }
    fn on_drop(&self, _path: &str) { ... }
}

The trait to be implemented when want to be notified about a new request and related metrics around it. When a request is performed (up to the point that a response is created) the on_response method is called with the corresponding metrics details. The on_request method will be called when the request is received, but not further processing has happened at this point.

Required Methods

fn on_request(&self, path: String)

Method will be called when a request has been received. path: the endpoint uri path

fn on_response( &self, path: String, latency: Duration, status: u16, grpc_status_code: Code, )

Method to be called from the server when a request is performed. path: the endpoint uri path latency: the time when the request was received and when the response was created status: the http status code of the response grpc_status_code: the grpc status code (see https://github.com/grpc/grpc/blob/master/doc/statuscodes.md#status-codes-and-their-use-in-grpc)

Provided Methods

fn on_error(&self, _latency: Duration, _grpc_status_code: Code)

Called when a gRPC request fails at the transport/middleware level (e.g. service panic, connection drop, timeout). gRPC application errors (non-OK status codes) are NOT reported here — they are already captured by on_response. The method path is not available at this layer (tower-http’s on_failure callback does not receive the response object).

fn on_start(&self, _path: &str)

Called when request call is started

fn on_drop(&self, _path: &str)

Called when request call is dropped. It is guaranteed that for each on_start there will be corresponding on_drop

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl MetricsCallbackProvider for DefaultMetricsCallbackProvider