Trait opentelemetry::sdk::metrics::View

source ·

pub trait View: Send + Sync + 'static {
    // Required method
    fn match_inst(&self, inst: &Instrument) -> Option<Stream>;
}

Expand description

Used to customize the metrics that are output by the SDK.

Here are some examples when a View might be needed:

Customize which Instruments are to be processed/ignored. For example, an instrumented library can provide both temperature and humidity, but the application developer might only want temperature.
Customize the aggregation - if the default aggregation associated with the Instrument does not meet the needs of the user. For example, an HTTP client library might expose HTTP client request duration as Histogram by default, but the application developer might only want the total count of outgoing requests.
Customize which attribute(s) are to be reported on metrics. For example, an HTTP server library might expose HTTP verb (e.g. GET, POST) and HTTP status code (e.g. 200, 301, 404). The application developer might only care about HTTP status code (e.g. reporting the total count of HTTP requests for each HTTP status code). There could also be extreme scenarios in which the application developer does not need any attributes (e.g. just get the total count of all incoming requests).

Example Custom View

View is implemented for all Fn(&Instrument) -> Option<Stream>.

use opentelemetry_sdk::metrics::{Instrument, MeterProvider, Stream};

// return streams for the given instrument
let my_view = |i: &Instrument| {
  // return Some(Stream) or
  None
};

let provider = MeterProvider::builder().with_view(my_view).build();