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Tracing is a powerful observability tool to understand more about a system, especially distributed systems. This is helpful in many things like debugging and performance monitoring. The example code below demonstrates a simple trace with OpenTelemetry in Go. The output shows the start and end time of the span, events, and attributes. With data like the sample output, you can use it with tools like ELK stack, Jaeger, Elastic APM, and AWS X-Ray to visualize and analyze the data.
func main() {
ctx := context.Background()
// Stdout exporter that prints to console
exporter, err := stdouttrace.New(stdouttrace.WithPrettyPrint())
if err != nil {
log.Fatalf("Failed to create an exporter: %v", err)
}
// Simple span processor
spanProcessor := trace.NewSimpleSpanProcessor(exporter)
// Tracer provider with the simple span processor
tp := trace.NewTracerProvider(
trace.WithSpanProcessor(spanProcessor),
trace.WithResource(resource.NewWithAttributes(
semconv.SchemaURL,
semconv.ServiceNameKey.String("SampleService"),
)),
)
defer func() {
if err := tp.Shutdown(ctx); err != nil {
log.Fatalf("Failed to shut down tracer provider: %v", err)
}
}()
// Tracer provider as the global provider
otel.SetTracerProvider(tp)
// Get a tracer
tracer := otel.Tracer("sample-tracer")
// Start a new span
_, span := tracer.Start(ctx, "sample-span")
log.Println("Sample log")
span.AddEvent("Sample event")
span.SetAttributes(attribute.KeyValue{Key: "user.id", Value: attribute.StringValue("12345")})
// End the span
span.End()
}Sample output after running go run main.go:
2024/05/10 19:12:01 Sample log
{
"Name": "sample-span",
"SpanContext": {
"TraceID": "8b0a15935aeb9645ea25d84c38895f48",
"SpanID": "9ae8ec6e761a2575",
"TraceFlags": "01",
"TraceState": "",
"Remote": false
},
"Parent": {
"TraceID": "00000000000000000000000000000000",
"SpanID": "0000000000000000",
"TraceFlags": "00",
"TraceState": "",
"Remote": false
},
"SpanKind": 1,
"StartTime": "2024-05-10T19:12:01.103389979+08:00",
"EndTime": "2024-05-10T19:12:01.103429453+08:00",
"Attributes": [
{
"Key": "user.id",
"Value": {
"Type": "STRING",
"Value": "12345"
}
}
],
"Events": [
{
"Name": "Sample event",
"Attributes": null,
"DroppedAttributeCount": 0,
"Time": "2024-05-10T19:12:01.103428558+08:00"
}
],
"Links": null,
"Status": {
"Code": "Unset",
"Description": ""
},
"DroppedAttributes": 0,
"DroppedEvents": 0,
"DroppedLinks": 0,
"ChildSpanCount": 0,
"Resource": [
{
"Key": "service.name",
"Value": {
"Type": "STRING",
"Value": "SampleService"
}
}
],
"InstrumentationLibrary": {
"Name": "sample-tracer",
"Version": "",
"SchemaURL": ""
}
}