package hlog

import "github.com/rs/zerolog/hlog"

Package hlog provides a set of http.Handler helpers for zerolog.

//go:build !binary_log
// +build !binary_log

package main

import (
	"net/http"
	"os"
	"time"

	"net/http/httptest"

	"github.com/rs/zerolog"
	"github.com/rs/zerolog/hlog"
)

// fake alice to avoid dep
type middleware func(http.Handler) http.Handler
type alice struct {
	m []middleware
}

func (a alice) Append(m middleware) alice {
	a.m = append(a.m, m)
	return a
}
func (a alice) Then(h http.Handler) http.Handler {
	for i := range a.m {
		h = a.m[len(a.m)-1-i](h)
	}
	return h
}

func init() {
	zerolog.TimestampFunc = func() time.Time {
		return time.Date(2001, time.February, 3, 4, 5, 6, 7, time.UTC)
	}
}

func main() {
	log := zerolog.New(os.Stdout).With().
		Timestamp().
		Str("role", "my-service").
		Str("host", "local-hostname").
		Logger()

	c := alice{}

	// Install the logger handler with default output on the console
	c = c.Append(hlog.NewHandler(log))

	// Install some provided extra handlers to set some request's context fields.
	// Thanks to those handlers, all our logs will come with some pre-populated fields.
	c = c.Append(hlog.RemoteAddrHandler("ip"))
	c = c.Append(hlog.UserAgentHandler("user_agent"))
	c = c.Append(hlog.RefererHandler("referer"))
	//c = c.Append(hlog.RequestIDHandler("req_id", "Request-Id"))

	// Here is your final handler
	h := c.Then(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Get the logger from the request's context. You can safely assume it
		// will be always there: if the handler is removed, hlog.FromRequest
		// will return a no-op logger.
		hlog.FromRequest(r).Info().
			Str("user", "current user").
			Str("status", "ok").
			Msg("Something happened")
	}))
	http.Handle("/", h)

	h.ServeHTTP(httptest.NewRecorder(), &http.Request{})

}

{"level":"info","role":"my-service","host":"local-hostname","user":"current user","status":"ok","time":"2001-02-03T04:05:06Z","message":"Something happened"}

Index ¶

• func AccessHandler(f func(r *http.Request, status, size int, duration time.Duration)) func(next http.Handler) http.Handler
• func CtxWithID(ctx context.Context, id xid.ID) context.Context
• func CustomHeaderHandler(fieldKey, header string) func(next http.Handler) http.Handler
• func EtagHandler(fieldKey string) func(next http.Handler) http.Handler
• func FromRequest(r *http.Request) *zerolog.Logger
• func HTTPVersionHandler(fieldKey string) func(next http.Handler) http.Handler
• func HostHandler(fieldKey string, trimPort ...bool) func(next http.Handler) http.Handler
• func IDFromCtx(ctx context.Context) (id xid.ID, ok bool)
• func IDFromRequest(r *http.Request) (id xid.ID, ok bool)
• func MethodHandler(fieldKey string) func(next http.Handler) http.Handler
• func NewHandler(log zerolog.Logger) func(http.Handler) http.Handler
• func ProtoHandler(fieldKey string) func(next http.Handler) http.Handler
• func RefererHandler(fieldKey string) func(next http.Handler) http.Handler
• func RemoteAddrHandler(fieldKey string) func(next http.Handler) http.Handler
• func RemoteIPHandler(fieldKey string) func(next http.Handler) http.Handler
• func RequestHandler(fieldKey string) func(next http.Handler) http.Handler
• func RequestIDHandler(fieldKey, headerName string) func(next http.Handler) http.Handler
• func ResponseHeaderHandler(fieldKey, headerName string) func(next http.Handler) http.Handler
• func URLHandler(fieldKey string) func(next http.Handler) http.Handler
• func UserAgentHandler(fieldKey string) func(next http.Handler) http.Handler

Examples ¶

• package (Handler)

Functions ¶

func AccessHandler ¶

func AccessHandler(f func(r *http.Request, status, size int, duration time.Duration)) func(next http.Handler) http.Handler

AccessHandler returns a handler that call f after each request.

func CtxWithID ¶

func CtxWithID(ctx context.Context, id xid.ID) context.Context

CtxWithID adds the given xid.ID to the context

func CustomHeaderHandler ¶

func CustomHeaderHandler(fieldKey, header string) func(next http.Handler) http.Handler

CustomHeaderHandler adds given header from request's header as a field to the context's logger using fieldKey as field key.

func EtagHandler ¶

func EtagHandler(fieldKey string) func(next http.Handler) http.Handler

EtagHandler adds Etag header from response's header as a field to the context's logger using fieldKey as field key.

func FromRequest ¶

func FromRequest(r *http.Request) *zerolog.Logger

FromRequest gets the logger in the request's context. This is a shortcut for log.Ctx(r.Context())

func HTTPVersionHandler ¶

func HTTPVersionHandler(fieldKey string) func(next http.Handler) http.Handler

HTTPVersionHandler is similar to ProtoHandler, but it does not store the "HTTP/" prefix in the protocol name.

func HostHandler ¶

func HostHandler(fieldKey string, trimPort ...bool) func(next http.Handler) http.Handler

HostHandler adds the request's host as a field to the context's logger using fieldKey as field key. If trimPort is set to true, then port is removed from the host.

func IDFromCtx ¶

func IDFromCtx(ctx context.Context) (id xid.ID, ok bool)

IDFromCtx returns the unique id associated to the context if any.

func IDFromRequest ¶

func IDFromRequest(r *http.Request) (id xid.ID, ok bool)

IDFromRequest returns the unique id associated to the request if any.

func MethodHandler ¶

func MethodHandler(fieldKey string) func(next http.Handler) http.Handler

MethodHandler adds the request method as a field to the context's logger using fieldKey as field key.

func NewHandler ¶

func NewHandler(log zerolog.Logger) func(http.Handler) http.Handler

NewHandler injects log into requests context.

func ProtoHandler ¶

func ProtoHandler(fieldKey string) func(next http.Handler) http.Handler

ProtoHandler adds the requests protocol version as a field to the context logger using fieldKey as field Key.

func RefererHandler ¶

func RefererHandler(fieldKey string) func(next http.Handler) http.Handler

RefererHandler adds the request's referer as a field to the context's logger using fieldKey as field key.

func RemoteAddrHandler ¶

func RemoteAddrHandler(fieldKey string) func(next http.Handler) http.Handler

RemoteAddrHandler adds the request's remote address as a field to the context's logger using fieldKey as field key.

func RemoteIPHandler ¶

func RemoteIPHandler(fieldKey string) func(next http.Handler) http.Handler

RemoteIPHandler is similar to RemoteAddrHandler, but logs only an IP, not a port.

func RequestHandler ¶

func RequestHandler(fieldKey string) func(next http.Handler) http.Handler

RequestHandler adds the request method and URL as a field to the context's logger using fieldKey as field key.

func RequestIDHandler ¶

func RequestIDHandler(fieldKey, headerName string) func(next http.Handler) http.Handler

RequestIDHandler returns a handler setting a unique id to the request which can be gathered using IDFromRequest(req). This generated id is added as a field to the logger using the passed fieldKey as field name. The id is also added as a response header if the headerName is not empty.

The generated id is a URL safe base64 encoded mongo object-id-like unique id. Mongo unique id generation algorithm has been selected as a trade-off between size and ease of use: UUID is less space efficient and snowflake requires machine configuration.

func ResponseHeaderHandler ¶

func ResponseHeaderHandler(fieldKey, headerName string) func(next http.Handler) http.Handler

func URLHandler ¶

func URLHandler(fieldKey string) func(next http.Handler) http.Handler

URLHandler adds the requested URL as a field to the context's logger using fieldKey as field key.

func UserAgentHandler ¶

func UserAgentHandler(fieldKey string) func(next http.Handler) http.Handler

UserAgentHandler adds the request's user-agent as a field to the context's logger using fieldKey as field key.

Source Files ¶

hlog.go

Directories ¶