Merge pull request #87 from instana/always_send_http_status_code

Always send HTTP status code

adapters.go

@@ -5,7 +5,6 @@ import (
 	"net/http"
 	"runtime"
 
-	"github.com/felixge/httpsnoop"
 	ot "github.com/opentracing/opentracing-go"
 	"github.com/opentracing/opentracing-go/ext"
 	otlog "github.com/opentracing/opentracing-go/log"
@@ -43,21 +42,12 @@ func (s *Sensor) TraceHandler(name, pattern string, handler http.HandlerFunc) (s
 func (s *Sensor) TracingHandler(name string, handler http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, req *http.Request) {
 		s.WithTracingContext(name, w, req, func(span ot.Span, ctx context.Context) {
-			// Capture response code for span
-			hooks := httpsnoop.Hooks{
-				WriteHeader: func(next httpsnoop.WriteHeaderFunc) httpsnoop.WriteHeaderFunc {
-					return func(code int) {
-						next(code)
-						span.SetTag(string(ext.HTTPStatusCode), code)
-					}
-				},
-			}
-
-			// Add hooks to response writer
-			wrappedWriter := httpsnoop.Wrap(w, hooks)
+			wrapped := &statusCodeRecorder{ResponseWriter: w}
+			handler.ServeHTTP(wrapped, req.WithContext(ctx))
 
-			// Serve original handler
-			handler.ServeHTTP(wrappedWriter, req.WithContext(ctx))
+			if wrapped.Status > 0 {
+				span.SetTag(string(ext.HTTPStatusCode), wrapped.Status)
+			}
 		})
 	}
 }
@@ -152,3 +142,22 @@ func (s *Sensor) WithTracingContext(name string, w http.ResponseWriter, req *htt
 		f(span, ctx)
 	})
 }
+
+// wrapper over http.ResponseWriter to spy the returned status code
+type statusCodeRecorder struct {
+	http.ResponseWriter
+	Status int
+}
+
+func (rec *statusCodeRecorder) WriteHeader(status int) {
+	rec.Status = status
+	rec.ResponseWriter.WriteHeader(status)
+}
+
+func (rec *statusCodeRecorder) Write(b []byte) (int, error) {
+	if rec.Status == 0 {
+		rec.Status = http.StatusOK
+	}
+
+	return rec.ResponseWriter.Write(b)
+}

go.mod

@@ -3,7 +3,6 @@ module github.com/instana/go-sensor
 go 1.8
 
 require (
-	github.com/felixge/httpsnoop v1.0.0
 	github.com/gogo/protobuf v1.2.1 // indirect
 	github.com/looplab/fsm v0.1.0
 	github.com/opentracing/basictracer-go v1.0.0

go.sum

@@ -1,7 +1,5 @@
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/felixge/httpsnoop v1.0.0 h1:gh8fMGz0rlOv/1WmRZm7OgncIOTsAj21iNJot48omJQ=
-github.com/felixge/httpsnoop v1.0.0/go.mod h1:3+D9sFq0ahK/JeJPhCBUV1xlf4/eIYrUQaxulT0VzX8=
 github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
 github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvWXihfKN4Q=
@@ -14,6 +12,7 @@ github.com/opentracing/opentracing-go v1.1.0 h1:pWlfV3Bxv7k65HYwkikxat0+s3pV4bsq
 github.com/opentracing/opentracing-go v1.1.0/go.mod h1:UkNAQd3GIcIGf0SeVgPpRdFStlNbqXla1AfSYxPUl2o=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=