opentracing

Documentation

Overview

Package opentracing is used to initialize the opentracing from the plugin, and supplies the OpenTracing http.RoundTripper and router middleware.

Index

• Variables
• func HTTPHandler(handler http.Handler, opt *Option) http.Handler
• func InitOpenTracingFromPlugin(pluginPath string, config interface{}) (err error)
• func MustInitOpenTracingFromPlugin(pluginPath string, config interface{})
• func OpenTracing(opt *Option) ship.Middleware
• func RegisterPluginOpts()
• type HTTPRoundTripper
  • func NewHTTPRoundTripper(rt http.RoundTripper, opt *Option) *HTTPRoundTripper
  • func (rt *HTTPRoundTripper) RoundTrip(req *http.Request) (*http.Response, error)
  • func (rt *HTTPRoundTripper) WrappedRoundTripper() http.RoundTripper
• type Option
  • func (o *Option) GetComponentName(req *http.Request) string
  • func (o *Option) GetTracer() opentracing.Tracer
  • func (o *Option) Init()

Examples

• OpenTracing

Variables

var PluginOptGroup = gconf.NewGroup("opentracing.plugin")

PluginOptGroup is the group of the OpenTracing plugin config options.

var PluginOpts = []gconf.Opt{
	gconf.StrOpt("path", "The path of the plugin implementing the OpenTracing tracer."),
	gconf.StrOpt("config", "The configuration information of the plugin."),
}

PluginOpts collects the options of the OpenTracing Plugin.

Functions

func HTTPHandler

func HTTPHandler(handler http.Handler, opt *Option) http.Handler

HTTPHandler is the same as OpenTracing, but returns a http.Handler.

func InitOpenTracingFromPlugin

func InitOpenTracingFromPlugin(pluginPath string, config interface{}) (err error)

InitOpenTracingFromPlugin initializes the OpenTracing implementation, which will load the implementation plugin and call the function InitOpenTracing with config.

The plugin must contain the function

func InitOpenTracing(config interface{}) error

Notice:

1. If config is empty, retry the env variable "OPENTRACING_PLUGIN_CONFIG".
2. If pluginPath is empty, retry the env variable "OPENTRACING_PLUGIN_PATH".
3. If pluginPath is empty, it returns nil and does nothing.

func MustInitOpenTracingFromPlugin

func MustInitOpenTracingFromPlugin(pluginPath string, config interface{})

MustInitOpenTracingFromPlugin is the same as InitOpenTracing, but logs the error and exits the program when an error occurs.

func OpenTracing

func OpenTracing(opt *Option) ship.Middleware

OpenTracing is a middleware to support OpenTracing, which extracts the span context from the http request header, creates a new span as the server span from the span context, and put it into the request context.

Example

func RegisterPluginOpts

func RegisterPluginOpts()

RegisterPluginOpts registers the options of opentracing plugin.

Types

type HTTPRoundTripper

type HTTPRoundTripper struct {
	http.RoundTripper
	Option
}

HTTPRoundTripper is a RoundTripper to support OpenTracing, which extracts the parent span from the context of the sent http.Request, then creates a new span by the context of the parent span for http.Request.

func NewHTTPRoundTripper

func NewHTTPRoundTripper(rt http.RoundTripper, opt *Option) *HTTPRoundTripper

NewHTTPRoundTripper returns a new HTTPRoundTripper.

func (*HTTPRoundTripper) RoundTrip

func (rt *HTTPRoundTripper) RoundTrip(req *http.Request) (*http.Response, error)

RoundTrip implements the interface http.RounderTripper.

func (*HTTPRoundTripper) WrappedRoundTripper

func (rt *HTTPRoundTripper) WrappedRoundTripper() http.RoundTripper

WrappedRoundTripper returns the wrapped http.RoundTripper.

type Option

type Option struct {
	Tracer        opentracing.Tracer // Default: opentracing.GlobalTracer()
	ComponentName string             // Default: use ComponentNameFunc(req)

	// ComponentNameFunc is used to get the component name if ComponentName
	// is empty.
	//
	// Default: "net/http"
	ComponentNameFunc func(*http.Request) string

	// URLTagFunc is used to get the value of the tag "http.url".
	//
	// Default: url.String()
	URLTagFunc func(*url.URL) string

	// SpanFilter is used to filter the span if returning true.
	//
	// Default: return false
	SpanFilter func(*http.Request) bool

	// OperationNameFunc is used to the operation name.
	//
	// Default: fmt.Sprintf("HTTP %s %s", r.Method, r.URL.Path)
	OperationNameFunc func(*http.Request) string

	// SpanObserver is used to do extra things of the span for the request.
	//
	// For example,
	//    OpenTracingOption {
	//        SpanObserver: func(*http.Request, opentracing.Span) {
	//            ext.PeerHostname.Set(span, req.Host)
	//        },
	//    }
	//
	// Default: Do nothing.
	SpanObserver func(*http.Request, opentracing.Span)
}

Option is used to configure the OpenTracing middleware and RoundTripper.

func (*Option) GetComponentName

func (o *Option) GetComponentName(req *http.Request) string

GetComponentName returns ComponentName if it is not empty. Or ComponentNameFunc(req) instead.

func (*Option) GetTracer

func (o *Option) GetTracer() opentracing.Tracer

GetTracer returns the OpenTracing tracker.

func (*Option) Init

func (o *Option) Init()

Init initializes the OpenTracingOption.