From 832c0e6c2d623ee51603a2353fdce999ee31cdef Mon Sep 17 00:00:00 2001
From: dmathieu <42@dmathieu.com>
Date: Wed, 6 Mar 2024 14:34:44 +0100
Subject: [PATCH] add span start end end options to gin configuration

---
 .../gin-gonic/gin/otelgin/gintrace.go         |  6 ++--
 .../gin-gonic/gin/otelgin/option.go           | 18 ++++++++++
 .../gin/otelgin/test/gintrace_test.go         | 34 +++++++++++++++++++
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/instrumentation/github.com/gin-gonic/gin/otelgin/gintrace.go b/instrumentation/github.com/gin-gonic/gin/otelgin/gintrace.go
index df0fbf9c52b..34ad848e034 100644
--- a/instrumentation/github.com/gin-gonic/gin/otelgin/gintrace.go
+++ b/instrumentation/github.com/gin-gonic/gin/otelgin/gintrace.go
@@ -58,10 +58,10 @@ func Middleware(service string, opts ...Option) gin.HandlerFunc {
 			c.Request = c.Request.WithContext(savedCtx)
 		}()
 		ctx := cfg.Propagators.Extract(savedCtx, propagation.HeaderCarrier(c.Request.Header))
-		opts := []oteltrace.SpanStartOption{
+		opts := append(cfg.SpanStartOptions, []oteltrace.SpanStartOption{
 			oteltrace.WithAttributes(semconvutil.HTTPServerRequest(service, c.Request)...),
 			oteltrace.WithSpanKind(oteltrace.SpanKindServer),
-		}
+		}...)
 		var spanName string
 		if cfg.SpanNameFormatter == nil {
 			spanName = c.FullPath()
@@ -75,7 +75,7 @@ func Middleware(service string, opts ...Option) gin.HandlerFunc {
 			opts = append(opts, oteltrace.WithAttributes(rAttr))
 		}
 		ctx, span := tracer.Start(ctx, spanName, opts...)
-		defer span.End()
+		defer span.End(cfg.SpanEndOptions...)
 
 		// pass the span through the request context
 		c.Request = c.Request.WithContext(ctx)
diff --git a/instrumentation/github.com/gin-gonic/gin/otelgin/option.go b/instrumentation/github.com/gin-gonic/gin/otelgin/option.go
index 113576ca00a..0772c41fab7 100644
--- a/instrumentation/github.com/gin-gonic/gin/otelgin/option.go
+++ b/instrumentation/github.com/gin-gonic/gin/otelgin/option.go
@@ -17,6 +17,8 @@ type config struct {
 	Propagators       propagation.TextMapPropagator
 	Filters           []Filter
 	SpanNameFormatter SpanNameFormatter
+	SpanStartOptions  []oteltrace.SpanStartOption
+	SpanEndOptions    []oteltrace.SpanEndOption
 }
 
 // Filter is a predicate used to determine whether a given http.request should
@@ -77,3 +79,19 @@ func WithSpanNameFormatter(f func(r *http.Request) string) Option {
 		c.SpanNameFormatter = f
 	})
 }
+
+// WithSpanStartOption applies options to all the HTTP span created by the
+// instrumentation.
+func WithSpanStartOption(o ...oteltrace.SpanStartOption) Option {
+	return optionFunc(func(c *config) {
+		c.SpanStartOptions = append(c.SpanStartOptions, o...)
+	})
+}
+
+// WithSpanEndOption applies options when ending the HTTP span created by the
+// instrumentation.
+func WithSpanEndOption(o ...oteltrace.SpanEndOption) Option {
+	return optionFunc(func(c *config) {
+		c.SpanEndOptions = append(c.SpanEndOptions, o...)
+	})
+}
diff --git a/instrumentation/github.com/gin-gonic/gin/otelgin/test/gintrace_test.go b/instrumentation/github.com/gin-gonic/gin/otelgin/test/gintrace_test.go
index afd6460983a..c2c9355b578 100644
--- a/instrumentation/github.com/gin-gonic/gin/otelgin/test/gintrace_test.go
+++ b/instrumentation/github.com/gin-gonic/gin/otelgin/test/gintrace_test.go
@@ -22,6 +22,7 @@ import (
 	"go.opentelemetry.io/otel/codes"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	"go.opentelemetry.io/otel/sdk/trace/tracetest"
+	"go.opentelemetry.io/otel/trace"
 
 	"go.opentelemetry.io/otel/attribute"
 	oteltrace "go.opentelemetry.io/otel/trace"
@@ -179,6 +180,39 @@ func TestSpanName(t *testing.T) {
 	}
 }
 
+func TestWithSpanStartOptions(t *testing.T) {
+	sr := tracetest.NewSpanRecorder()
+	provider := sdktrace.NewTracerProvider(sdktrace.WithSpanProcessor(sr))
+
+	// setup
+	router := gin.New()
+	router.Use(otelgin.Middleware(
+		"foobar",
+		otelgin.WithTracerProvider(provider),
+		otelgin.WithSpanStartOption(
+			trace.WithAttributes(attribute.String("spanStart", "true")),
+		),
+	))
+
+	// configure a handler that returns an error and 5xx status
+	// code
+	router.GET("/", func(c *gin.Context) {
+	})
+	r := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, r)
+	response := w.Result()
+	assert.Equal(t, http.StatusOK, response.StatusCode)
+
+	// verify the errors and status are correct
+	spans := sr.Ended()
+	require.Len(t, spans, 1)
+	span := spans[0]
+	assert.Equal(t, "/", span.Name())
+	attr := span.Attributes()
+	assert.Contains(t, attr, attribute.String("spanStart", "true"))
+}
+
 func TestHTML(t *testing.T) {
 	sr := tracetest.NewSpanRecorder()
 	provider := sdktrace.NewTracerProvider(sdktrace.WithSpanProcessor(sr))