http_metrics

import "github.com/improbable-eng/go-httpwares/metrics"

• Overview
• Imported Packages
• Index
• Examples

Overview

http_metrics provides client and server side reporting of HTTP stats.

The middleware (server-side) or tripperware (client-side) must be given a reporter to record the stats for each request.

Prometheus-based reporter implementations for client and server metrics are included. The user may choose what level of detail is included using options to these reporters.

Imported Packages

• github.com/improbable-eng/go-httpwares

Index

• func Middleware(reporter Reporter) httpwares.Middleware
• func Tripperware(reporter Reporter) httpwares.Tripperware
• type Reporter
• type Tracker

Examples

• Middleware
• Tripperware

Package files

doc.go middleware.go reporter.go tripperware.go wrapped_body.go wrapped_writer.go

func Middleware

func Middleware(reporter Reporter) httpwares.Middleware

Middleware returns a http.Handler middleware that exports request metrics. If the tags middleware is used, this should be placed after tags to pick up metadata. This middleware assumes HTTP/1.x-style requests/response behaviour. It will not work with servers that use hijacking, pushing, or other similar features.

Example:

r := chi.NewRouter()
r.Use(http_ctxtags.Middleware("default"))
r.Use(http_metrics.Middleware(http_prometheus.ServerMetrics(http_prometheus.WithLatency())))
r.Get("/", func(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(200)
})
http.ListenAndServe(":8888", r)

func Tripperware

func Tripperware(reporter Reporter) httpwares.Tripperware

Tripperware returns a new client-side ware that exports request metrics. If the tags tripperware is used, this should be placed after tags to pick up metadata.

Example:

c := httpwares.WrapClient(
    http.DefaultClient,
    http_ctxtags.Tripperware(),
    http_metrics.Tripperware(http_prometheus.ClientMetrics(http_prometheus.WithName("testclient"))),
)
c.Get("example.org/foo")

type Reporter

type Reporter interface {
    // Start tracking a new request.
    Track(req *http.Request) Tracker
}

Called when a new request is to be tracked.

type Tracker

type Tracker interface {
    // The exchange has started. This is called immediately after Reporter.Track.
    // On the client, this is called before any data is sent.
    // On the server, this is called after headers have been parsed.
    RequestStarted()
    // The request body has been read to EOF or closed, whichever comes first.
    // On the client, this is called when the transport completes sending the request.
    // On the server, this is called when the handler completes reading the request, and may be omitted.
    RequestRead(duration time.Duration, size int)
    // The handling of the response has started.
    // On the client, this is called after the response headers have been parsed.
    // On the server, this is called before any data is written.
    ResponseStarted(duration time.Duration, status int, header http.Header)
    // The response has completed.
    // On the client, this is called when the body is read to EOF or closed, whichever comes first, and may be omitted.
    // On the server, this is called when the handler returns and has therefore completed writing the response.
    ResponseDone(duration time.Duration, status int, size int)
}

Receives events about a tracked request.

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