/
gintrace.go
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/
gintrace.go
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// Copyright The OpenTelemetry 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.
// Based on https://github.com/DataDog/dd-trace-go/blob/8fb554ff7cf694267f9077ae35e27ce4689ed8b6/contrib/gin-gonic/gin/gintrace.go
package otelgin // import "go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin"
import (
"fmt"
"github.com/gin-gonic/gin"
"go.opentelemetry.io/otel"
"go.opentelemetry.io/otel/codes"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/propagation"
semconv "go.opentelemetry.io/otel/semconv/v1.10.0"
oteltrace "go.opentelemetry.io/otel/trace"
)
const (
tracerKey = "otel-go-contrib-tracer"
tracerName = "go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin"
)
// Middleware returns middleware that will trace incoming requests.
// The service parameter should describe the name of the (virtual)
// server handling the request.
func Middleware(service string, opts ...Option) gin.HandlerFunc {
cfg := config{}
for _, opt := range opts {
opt.apply(&cfg)
}
if cfg.TracerProvider == nil {
cfg.TracerProvider = otel.GetTracerProvider()
}
tracer := cfg.TracerProvider.Tracer(
tracerName,
oteltrace.WithInstrumentationVersion(SemVersion()),
)
if cfg.Propagators == nil {
cfg.Propagators = otel.GetTextMapPropagator()
}
return func(c *gin.Context) {
c.Set(tracerKey, tracer)
savedCtx := c.Request.Context()
defer func() {
c.Request = c.Request.WithContext(savedCtx)
}()
ctx := cfg.Propagators.Extract(savedCtx, propagation.HeaderCarrier(c.Request.Header))
opts := []oteltrace.SpanStartOption{
oteltrace.WithAttributes(semconv.NetAttributesFromHTTPRequest("tcp", c.Request)...),
oteltrace.WithAttributes(semconv.EndUserAttributesFromHTTPRequest(c.Request)...),
oteltrace.WithAttributes(semconv.HTTPServerAttributesFromHTTPRequest(service, c.FullPath(), c.Request)...),
oteltrace.WithSpanKind(oteltrace.SpanKindServer),
}
spanName := c.FullPath()
if spanName == "" {
spanName = fmt.Sprintf("HTTP %s route not found", c.Request.Method)
}
ctx, span := tracer.Start(ctx, spanName, opts...)
defer span.End()
// pass the span through the request context
c.Request = c.Request.WithContext(ctx)
// serve the request to the next middleware
c.Next()
status := c.Writer.Status()
attrs := semconv.HTTPAttributesFromHTTPStatusCode(status)
spanStatus, spanMessage := semconv.SpanStatusFromHTTPStatusCodeAndSpanKind(status, oteltrace.SpanKindServer)
span.SetAttributes(attrs...)
span.SetStatus(spanStatus, spanMessage)
if len(c.Errors) > 0 {
span.SetAttributes(attribute.String("gin.errors", c.Errors.String()))
}
}
}
// HTML will trace the rendering of the template as a child of the
// span in the given context. This is a replacement for
// gin.Context.HTML function - it invokes the original function after
// setting up the span.
func HTML(c *gin.Context, code int, name string, obj interface{}) {
var tracer oteltrace.Tracer
tracerInterface, ok := c.Get(tracerKey)
if ok {
tracer, ok = tracerInterface.(oteltrace.Tracer)
}
if !ok {
tracer = otel.GetTracerProvider().Tracer(
tracerName,
oteltrace.WithInstrumentationVersion(SemVersion()),
)
}
savedContext := c.Request.Context()
defer func() {
c.Request = c.Request.WithContext(savedContext)
}()
opt := oteltrace.WithAttributes(attribute.String("go.template", name))
_, span := tracer.Start(savedContext, "gin.renderer.html", opt)
defer func() {
if r := recover(); r != nil {
err := fmt.Errorf("error rendering template:%s: %s", name, r)
span.RecordError(err)
span.SetStatus(codes.Error, "template failure")
span.End()
panic(r)
} else {
span.End()
}
}()
c.HTML(code, name, obj)
}