/
server.go
75 lines (67 loc) · 1.99 KB
/
server.go
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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
package main
import (
"context"
"html/template"
"log"
"net/http"
"github.com/gin-gonic/gin"
"go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/attribute"
stdout "go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
"go.opentelemetry.io/otel/propagation"
sdktrace "go.opentelemetry.io/otel/sdk/trace"
oteltrace "go.opentelemetry.io/otel/trace"
)
var tracer = otel.Tracer("gin-server")
func main() {
tp, err := initTracer()
if err != nil {
log.Fatal(err)
}
defer func() {
if err := tp.Shutdown(context.Background()); err != nil {
log.Printf("Error shutting down tracer provider: %v", err)
}
}()
r := gin.New()
r.Use(otelgin.Middleware("my-server"))
tmplName := "user"
tmplStr := "user {{ .name }} (id {{ .id }})\n"
tmpl := template.Must(template.New(tmplName).Parse(tmplStr))
r.SetHTMLTemplate(tmpl)
r.GET("/users/:id", func(c *gin.Context) {
id := c.Param("id")
name := getUser(c, id)
otelgin.HTML(c, http.StatusOK, tmplName, gin.H{
"name": name,
"id": id,
})
})
_ = r.Run(":8080")
}
func initTracer() (*sdktrace.TracerProvider, error) {
exporter, err := stdout.New(stdout.WithPrettyPrint())
if err != nil {
return nil, err
}
tp := sdktrace.NewTracerProvider(
sdktrace.WithSampler(sdktrace.AlwaysSample()),
sdktrace.WithBatcher(exporter),
)
otel.SetTracerProvider(tp)
otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
return tp, nil
}
func getUser(c *gin.Context, id string) string {
// Pass the built-in `context.Context` object from http.Request to OpenTelemetry APIs
// where required. It is available from gin.Context.Request.Context()
_, span := tracer.Start(c.Request.Context(), "getUser", oteltrace.WithAttributes(attribute.String("id", id)))
defer span.End()
if id == "123" {
return "otelgin tester"
}
return "unknown"
}