1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
package opencensus
// Copyright 2018 Microsoft Corporation
//
// 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.
import (
"context"
"fmt"
"net/http"
"os"
"contrib.go.opencensus.io/exporter/ocagent"
"github.com/Azure/go-autorest/tracing"
"go.opencensus.io/plugin/ochttp"
"go.opencensus.io/plugin/ochttp/propagation/tracecontext"
"go.opencensus.io/stats/view"
"go.opencensus.io/trace"
_ "gopkg.in/yaml.v2" // allows us to explicitly update the version without updating other dependencies
)
func init() {
enableFromEnv()
}
// split out for testing purposes
func enableFromEnv() {
if _, ok := os.LookupEnv("AZURE_SDK_TRACING_ENABLED"); ok {
agentEndpoint, ok := os.LookupEnv("OCAGENT_TRACE_EXPORTER_ENDPOINT")
if ok {
EnableWithAIForwarding(agentEndpoint)
} else {
Enable()
}
}
}
var defaultTracer = newocTracer()
type ocTracer struct {
// Sampler is the tracing sampler. If tracing is disabled it will never sample. Otherwise
// it will be using the parent sampler or the default.
sampler trace.Sampler
// Views for metric instrumentation.
views map[string]*view.View
// the trace exporter
traceExporter trace.Exporter
}
func newocTracer() *ocTracer {
return &ocTracer{
sampler: trace.NeverSample(),
views: map[string]*view.View{},
}
}
// NewTransport returns a new instance of a tracing-aware RoundTripper.
func (oct ocTracer) NewTransport(base *http.Transport) http.RoundTripper {
return &ochttp.Transport{
Base: base,
Propagation: &tracecontext.HTTPFormat{},
GetStartOptions: func(*http.Request) trace.StartOptions {
return trace.StartOptions{
Sampler: oct.sampler,
}
},
}
}
// StartSpan starts a trace span
func (oct ocTracer) StartSpan(ctx context.Context, name string) context.Context {
ctx, _ = trace.StartSpan(ctx, name, trace.WithSampler(oct.sampler))
return ctx
}
// EndSpan ends a previously started span stored in the context
func (oct ocTracer) EndSpan(ctx context.Context, httpStatusCode int, err error) {
span := trace.FromContext(ctx)
if span == nil {
return
}
if err != nil {
span.SetStatus(trace.Status{Message: err.Error(), Code: toTraceStatusCode(httpStatusCode)})
}
span.End()
}
// Enable will start instrumentation for metrics and traces.
func Enable() error {
defaultTracer.sampler = nil
// register the views for HTTP metrics
clientViews := []*view.View{
ochttp.ClientCompletedCount,
ochttp.ClientRoundtripLatencyDistribution,
ochttp.ClientReceivedBytesDistribution,
ochttp.ClientSentBytesDistribution,
}
for _, cv := range clientViews {
vn := fmt.Sprintf("Azure/go-autorest/tracing/opencensus-%s", cv.Name)
defaultTracer.views[vn] = cv.WithName(vn)
err := view.Register(defaultTracer.views[vn])
if err != nil {
return err
}
}
tracing.Register(defaultTracer)
return nil
}
// Disable will disable instrumentation for metrics and traces.
func Disable() {
// unregister any previously registered metrics
for _, v := range defaultTracer.views {
view.Unregister(v)
}
defaultTracer.sampler = trace.NeverSample()
if defaultTracer.traceExporter != nil {
trace.UnregisterExporter(defaultTracer.traceExporter)
}
tracing.Register(nil)
}
// EnableWithAIForwarding will start instrumentation and will connect to app insights forwarder
// exporter making the metrics and traces available in app insights.
func EnableWithAIForwarding(agentEndpoint string) error {
err := Enable()
if err != nil {
return err
}
defaultTracer.traceExporter, err = ocagent.NewExporter(ocagent.WithInsecure(), ocagent.WithAddress(agentEndpoint))
if err != nil {
return err
}
trace.RegisterExporter(defaultTracer.traceExporter)
return nil
}
// toTraceStatusCode converts HTTP Codes to OpenCensus codes as defined
// at https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/HTTP.md#status
func toTraceStatusCode(httpStatusCode int) int32 {
switch {
case http.StatusOK <= httpStatusCode && httpStatusCode < http.StatusBadRequest:
return trace.StatusCodeOK
case httpStatusCode == http.StatusBadRequest:
return trace.StatusCodeInvalidArgument
case httpStatusCode == http.StatusUnauthorized: // 401 is actually unauthenticated.
return trace.StatusCodeUnauthenticated
case httpStatusCode == http.StatusForbidden:
return trace.StatusCodePermissionDenied
case httpStatusCode == http.StatusNotFound:
return trace.StatusCodeNotFound
case httpStatusCode == http.StatusTooManyRequests:
return trace.StatusCodeResourceExhausted
case httpStatusCode == 499:
return trace.StatusCodeCancelled
case httpStatusCode == http.StatusNotImplemented:
return trace.StatusCodeUnimplemented
case httpStatusCode == http.StatusServiceUnavailable:
return trace.StatusCodeUnavailable
case httpStatusCode == http.StatusGatewayTimeout:
return trace.StatusCodeDeadlineExceeded
default:
return trace.StatusCodeUnknown
}
}
|
