ochttp

Documentation

Overview

Package ochttp contains:

- a propagation.HTTPFormat implementation for B3 and Datadog propagation

Index

• type HTTPFormat
  • func (f *HTTPFormat) SpanContextFromRequest(req *http.Request) (sc oc_trace.SpanContext, ok bool)
  • func (f *HTTPFormat) SpanContextToRequest(sc oc_trace.SpanContext, req *http.Request)

Types

type HTTPFormat

type HTTPFormat struct{}

HTTPFormat implements propagation.HTTPFormat to propagate traces in HTTP headers in B3 and Datadog propagation format. HTTPFormat skips the X-B3-ParentId and X-B3-Flags headers because there are additional fields not represented in the OpenCensus span context. Spans created from the incoming header will be the direct children of the client-side span. Similarly, receiver of the outgoing spans should use client-side span created by OpenCensus as the parent.

The HTTPFormat is based on ochttp and ddtrace. - ochttp: https://github.com/census-instrumentation/opencensus-go/tree/master/plugin/ochttp/propagation/b3 - ddtrace: https://github.com/DataDog/dd-trace-go/blob/v1/ddtrace/tracer/textmap.go See https://github.com/openzipkin/b3-propagation for more details on B3 propagation.

Examples

An example of using the propagator

func ListenAndServe(port string, handler http.Handler) error {
	ocHandler := new(oc_http.Handler)
	ocHandler.Handler = handler
	ocHandler.Propagation = new(HTTPFormat)

	server = http.Server{
		Addr:    ":" + port,
		Handler: ocHandler,
	}

	return server.ListenAndServe()
}

func (*HTTPFormat) SpanContextFromRequest

func (f *HTTPFormat) SpanContextFromRequest(req *http.Request) (sc oc_trace.SpanContext, ok bool)

SpanContextFromRequest extracts an OC span context from incoming requests. Will first try to extract from Datadog headers and then from B3 headers.

func (*HTTPFormat) SpanContextToRequest

func (f *HTTPFormat) SpanContextToRequest(sc oc_trace.SpanContext, req *http.Request)

SpanContextToRequest modifies the given request to include B3 and Datadog headers.