Package hlog

package hlog_test

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 Example_handler() {
    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{})

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

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 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 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 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 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.

Subdirectories