Struct replicante_util_iron::MetricsMiddleware

pub struct MetricsMiddleware { /* fields omitted */ }

An Iron middlewere to collect metrics about endpoints.

This middlewere collects the following information:

• The duration of endpoints as an histogram.
• The number of requests that return an error.
• The count of responses by method, path, HTTP status code.

Methods

impl MetricsMiddleware

pub fn metrics<S: Into<String>>(
    prefix: S
) -> (HistogramVec, CounterVec, CounterVec)

Generates the metrics needed my the middleware.

The three metrics returned (duration, erorrs, requests) are configured with the minimum requirements to be passed to MetricsMiddleware::new.

Metric names are prefixed with the given prefix and have the following attributes:

• Name: <PEFIX>_endpoint_duration. Description: Duration (in seconds) of HTTP endpoints. Static labels: none. Dynamic labels: method, path.

• Name: <PEFIX>_endpoint_errors. Description: Number of errors encountered while handling requests. Static labels: none. Dynamic labels: method, path.

• Name: <PEFIX>_endpoint_requests. Description: Unable to configure requests counter. Static labels: none. Dynamic labels: method, path, status.

pub fn new(
    duration: HistogramVec,
    errors: CounterVec,
    requests: CounterVec,
    logger: Logger
) -> MetricsMiddleware

Constructs a new MetricsMiddleware to record metrics about handlers.

The metrics to record observations in are passed to this method and must match the below requirements:

• The duration HistogramVec must have exactly two variable labels: ["method", "path"].
• The errors CounterVec must have exactly two variable labels: ["method", "path"].
• The requests HistogramVec must have exactly three variable labels: ["method", "path", "status"].
• None of the variable labels above can be constant labels.

Panics

This method validates the given metrics against the requirements and panics if any is not met.

pub fn into_middleware(self) -> (MetricsBefore, MetricsAfter)

Converts the middlewere into Iron's BeforeMiddleware and AfterMiddleware.