Source: span_annotating_client_trace.go in package go.opencensus.io/plugin/ochttp

Copyright 2018, OpenCensus Authors Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.


package ochttp

import (
	"crypto/tls"
	"net/http"
	"net/http/httptrace"
	"strings"

	"go.opencensus.io/trace"
)

type spanAnnotator struct {
	sp *trace.Span
}

TODO: Remove NewSpanAnnotator at the next release.

NewSpanAnnotator returns a httptrace.ClientTrace which annotates all emitted httptrace events on the provided Span. Deprecated: Use NewSpanAnnotatingClientTrace instead

func NewSpanAnnotator(r *http.Request, s *trace.Span) *httptrace.ClientTrace {
	return NewSpanAnnotatingClientTrace(r, s)
}

NewSpanAnnotatingClientTrace returns a httptrace.ClientTrace which annotates all emitted httptrace events on the provided Span.

func NewSpanAnnotatingClientTrace(_ *http.Request, s *trace.Span) *httptrace.ClientTrace {
	sa := spanAnnotator{sp: s}

	return &httptrace.ClientTrace{
		GetConn:              sa.getConn,
		GotConn:              sa.gotConn,
		PutIdleConn:          sa.putIdleConn,
		GotFirstResponseByte: sa.gotFirstResponseByte,
		Got100Continue:       sa.got100Continue,
		DNSStart:             sa.dnsStart,
		DNSDone:              sa.dnsDone,
		ConnectStart:         sa.connectStart,
		ConnectDone:          sa.connectDone,
		TLSHandshakeStart:    sa.tlsHandshakeStart,
		TLSHandshakeDone:     sa.tlsHandshakeDone,
		WroteHeaders:         sa.wroteHeaders,
		Wait100Continue:      sa.wait100Continue,
		WroteRequest:         sa.wroteRequest,
	}
}

func (s spanAnnotator) getConn(hostPort string) {
	attrs := []trace.Attribute{
		trace.StringAttribute("httptrace.get_connection.host_port", hostPort),
	}
	s.sp.Annotate(attrs, "GetConn")
}

func (s spanAnnotator) gotConn(info httptrace.GotConnInfo) {
	attrs := []trace.Attribute{
		trace.BoolAttribute("httptrace.got_connection.reused", info.Reused),
		trace.BoolAttribute("httptrace.got_connection.was_idle", info.WasIdle),
	}
	if info.WasIdle {
		attrs = append(attrs,
			trace.StringAttribute("httptrace.got_connection.idle_time", info.IdleTime.String()))
	}
	s.sp.Annotate(attrs, "GotConn")
}

PutIdleConn implements a httptrace.ClientTrace hook

func (s spanAnnotator) putIdleConn(err error) {
	var attrs []trace.Attribute
	if err != nil {
		attrs = append(attrs,
			trace.StringAttribute("httptrace.put_idle_connection.error", err.Error()))
	}
	s.sp.Annotate(attrs, "PutIdleConn")
}

func (s spanAnnotator) gotFirstResponseByte() {
	s.sp.Annotate(nil, "GotFirstResponseByte")
}

func (s spanAnnotator) got100Continue() {
	s.sp.Annotate(nil, "Got100Continue")
}

func (s spanAnnotator) dnsStart(info httptrace.DNSStartInfo) {
	attrs := []trace.Attribute{
		trace.StringAttribute("httptrace.dns_start.host", info.Host),
	}
	s.sp.Annotate(attrs, "DNSStart")
}

func (s spanAnnotator) dnsDone(info httptrace.DNSDoneInfo) {
	var addrs []string
	for _, addr := range info.Addrs {
		addrs = append(addrs, addr.String())
	}
	attrs := []trace.Attribute{
		trace.StringAttribute("httptrace.dns_done.addrs", strings.Join(addrs, " , ")),
	}
	if info.Err != nil {
		attrs = append(attrs,
			trace.StringAttribute("httptrace.dns_done.error", info.Err.Error()))
	}
	s.sp.Annotate(attrs, "DNSDone")
}

func (s spanAnnotator) connectStart(network, addr string) {
	attrs := []trace.Attribute{
		trace.StringAttribute("httptrace.connect_start.network", network),
		trace.StringAttribute("httptrace.connect_start.addr", addr),
	}
	s.sp.Annotate(attrs, "ConnectStart")
}

func (s spanAnnotator) connectDone(network, addr string, err error) {
	attrs := []trace.Attribute{
		trace.StringAttribute("httptrace.connect_done.network", network),
		trace.StringAttribute("httptrace.connect_done.addr", addr),
	}
	if err != nil {
		attrs = append(attrs,
			trace.StringAttribute("httptrace.connect_done.error", err.Error()))
	}
	s.sp.Annotate(attrs, "ConnectDone")
}

func (s spanAnnotator) tlsHandshakeStart() {
	s.sp.Annotate(nil, "TLSHandshakeStart")
}

func (s spanAnnotator) tlsHandshakeDone(_ tls.ConnectionState, err error) {
	var attrs []trace.Attribute
	if err != nil {
		attrs = append(attrs,
			trace.StringAttribute("httptrace.tls_handshake_done.error", err.Error()))
	}
	s.sp.Annotate(attrs, "TLSHandshakeDone")
}

func (s spanAnnotator) wroteHeaders() {
	s.sp.Annotate(nil, "WroteHeaders")
}

func (s spanAnnotator) wait100Continue() {
	s.sp.Annotate(nil, "Wait100Continue")
}

func (s spanAnnotator) wroteRequest(info httptrace.WroteRequestInfo) {
	var attrs []trace.Attribute
	if info.Err != nil {
		attrs = append(attrs,
			trace.StringAttribute("httptrace.wrote_request.error", info.Err.Error()))
	}
	s.sp.Annotate(attrs, "WroteRequest")