httpmetrics

Documentation

Overview

Package httpmetrics provides an http.Handler for collecting metrics about http servers.

Metrics are prefixed with:

http.server.<method>.<normalized path>
http.server.all

For example, a request to GET /apps/:foo/bars/:bar_id emits metrics prefixed with:

http.server.get.apps.foo.bars.bar-id
http.server.all

For each unique path, and under the global all prefix, servers will report:

requests - counter of requests
request-duration.ms - histogram of request durations in milliseconds
response-statuses.<status code> - counter of response status codes, eg 200

Example

This example demonstrates how to set up metrics and what will be collected on requests

// Create a new Metrics Provider
provider := testmetrics.NewProvider(&testing.T{})
r := chi.NewRouter()

// Use the Metrics Provider to create a new HTTP Handler
r.Use(func(next http.Handler) http.Handler {
	return NewServer(provider, next)
})

// Metrics will be collected around http OK statuses
// For all requests and for /foo requests
r.Get("/foo", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusOK)
}))

// Metrics will be collected around http Bad Request statuses
// For all requests and for /bar requests
r.Get("/bar", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusBadRequest)
}))

server := httptest.NewServer(r)
defer server.Close()

// Metrics will be collected for each request
req, _ := http.NewRequest("GET", server.URL+"/foo", nil)
if _, err := http.DefaultClient.Do(req); err != nil {
	fmt.Println(err)
}

req, _ = http.NewRequest("GET", server.URL+"/bar", nil)
if _, err := http.DefaultClient.Do(req); err != nil {
	fmt.Println(err)
}

provider.PrintCounterValue("http.server.get.bar.response-statuses.400")
provider.PrintCounterValue("http.server.all.requests")
provider.PrintCounterValue("http.server.all.response-statuses.200")
provider.PrintCounterValue("http.server.get.foo.requests")
provider.PrintCounterValue("http.server.get.foo.response-statuses.200")
provider.PrintCounterValue("http.server.all.response-statuses.400")
provider.PrintCounterValue("http.server.get.bar.requests")

Output:

http.server.get.bar.response-statuses.400: 1
http.server.all.requests: 2
http.server.all.response-statuses.200: 1
http.server.get.foo.requests: 1
http.server.get.foo.response-statuses.200: 1
http.server.all.response-statuses.400: 1
http.server.get.bar.requests: 1

Index

• func NewServer(p metrics.Provider, next http.Handler) http.Handler

Examples

• Package

Functions

func NewServer

func NewServer(p metrics.Provider, next http.Handler) http.Handler

NewServer returns an http.Handler which calls next for each request and reports metrics to the given provider.