twirp

Documentation

Overview

Package twirp provides tracing functions for tracing clients and servers generated by the twirp framework (https://github.com/twitchtv/twirp).

Index

• func NewServerHooks(opts ...Option) *twirp.ServerHooks
• func WrapServer(h http.Handler, opts ...Option) http.Handler
• type HTTPClient
  • func WrapClient(c HTTPClient, opts ...Option) HTTPClient
• type Option
  • func WithAnalytics(on bool) Option
  • func WithAnalyticsRate(rate float64) Option
  • func WithServiceName(name string) Option

Examples

• WrapClient
• WrapServer

Functions

func NewServerHooks

func NewServerHooks(opts ...Option) *twirp.ServerHooks

NewServerHooks creates the callback hooks for a twirp server to perform tracing. It is used in conjunction with WrapServer.

func WrapServer

func WrapServer(h http.Handler, opts ...Option) http.Handler

WrapServer wraps an http.Handler to add distributed tracing to a Twirp server.

Example

package main

import (
	"context"
	"net/http"

	twirptrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/twitchtv/twirp"
	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"

	"github.com/twitchtv/twirp/example"
)

type hatmaker struct{}

func (hatmaker) MakeHat(_ context.Context, _ *example.Size) (*example.Hat, error) {
	return &example.Hat{
		Size:  42,
		Color: "cornflower blue",
		Name:  "oversized blue hat",
	}, nil
}

func main() {
	tracer.Start()
	defer tracer.Stop()

	server := example.NewHaberdasherServer(hatmaker{}, twirptrace.NewServerHooks())
	traced := twirptrace.WrapServer(server)
	http.ListenAndServe(":8080", traced)
}

Types

type HTTPClient

type HTTPClient interface {
	Do(req *http.Request) (*http.Response, error)
}

HTTPClient is duplicated from twirp's generated service code. It is declared in this package so that the client can be wrapped to initiate traces.

func WrapClient

func WrapClient(c HTTPClient, opts ...Option) HTTPClient

WrapClient wraps an HTTPClient to add distributed tracing to its requests.

Example

package main

import (
	"context"
	"fmt"
	"net/http"

	twirptrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/twitchtv/twirp"
	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"

	"github.com/twitchtv/twirp/example"
)

func main() {
	tracer.Start()
	defer tracer.Stop()

	client := example.NewHaberdasherJSONClient("http://localhost:8080", twirptrace.WrapClient(&http.Client{}))
	for i := 0; i < 10; i++ {
		hat, err := client.MakeHat(context.Background(), &example.Size{Inches: 6})
		if err != nil {
			fmt.Println("error making hat:", err)
			continue
		}
		fmt.Println("made hat:", hat)
	}
}

type Option

type Option func(*config)

Option represents an option that can be passed to Dial.

func WithAnalytics

func WithAnalytics(on bool) Option

WithAnalytics enables Trace Analytics for all started spans.

func WithAnalyticsRate

func WithAnalyticsRate(rate float64) Option

WithAnalyticsRate sets the sampling rate for Trace Analytics events correlated to started spans.

func WithServiceName

func WithServiceName(name string) Option

WithServiceName sets the given service name for the dialled connection. When the service name is not explicitly set, it will be inferred based on the request to the twirp service.