Use content length if available.

If not, try using SDK functions.

extension/agenthealth/handler/stats/client/client.go

@@ -75,11 +75,20 @@ func (csh *clientStatsHandler) HandleRequest(ctx context.Context, r *http.Reques
 	}
 	requestID := csh.getRequestID(ctx)
 	recorder := &requestRecorder{start: time.Now()}
-	if r.GetBody != nil {
-		body, err := r.GetBody()
-		if err == nil {
-			recorder.payloadBytes, err = io.Copy(io.Discard, body)
+	if r.ContentLength != 0 {
+		recorder.payloadBytes = r.ContentLength
+	} else if r.Body != nil {
+		rsc, ok := r.Body.(aws.ReaderSeekerCloser)
+		if !ok {
+			rsc = aws.ReadSeekCloser(r.Body)
 		}
+		length, _ := aws.SeekerLen(rsc)
+		if length == -1 {
+			if body, err := r.GetBody(); err == nil {
+				length, _ = io.Copy(io.Discard, body)
+			}
+		}
+		recorder.payloadBytes = length
 	}
 	csh.requestCache.Set(requestID, recorder, ttlcache.DefaultTTL)
 }

extension/agenthealth/handler/stats/client/client_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/amazon-contributing/opentelemetry-collector-contrib/extension/awsmiddleware"
+	"github.com/aws/aws-sdk-go/aws"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -28,6 +29,7 @@ func TestHandle(t *testing.T) {
 	body := []byte("test payload size")
 	req, err := http.NewRequest("", "localhost", bytes.NewBuffer(body))
 	require.NoError(t, err)
+	req.ContentLength = 20
 	ctx := context.Background()
 	handler.HandleRequest(ctx, req)
 	got := handler.Stats(operation)
@@ -41,6 +43,25 @@ func TestHandle(t *testing.T) {
 	assert.NotNil(t, got.PayloadBytes)
 	assert.NotNil(t, got.StatusCode)
 	assert.Equal(t, http.StatusOK, *got.StatusCode)
-	assert.Equal(t, 17, *got.PayloadBytes)
+	assert.Equal(t, 20, *got.PayloadBytes)
 	assert.GreaterOrEqual(t, *got.LatencyMillis, int64(1))
+
+	// without content length
+	req.ContentLength = 0
+	handler.HandleRequest(ctx, req)
+	handler.HandleResponse(ctx, &http.Response{StatusCode: http.StatusOK})
+	got = handler.Stats(operation)
+	assert.NotNil(t, got.PayloadBytes)
+	assert.Equal(t, 17, *got.PayloadBytes)
+
+	// with seeker
+	body = append(body, " with seeker"...)
+	req, err = http.NewRequest("", "localhost", aws.ReadSeekCloser(bytes.NewReader(body)))
+	require.NoError(t, err)
+	req.ContentLength = 0
+	handler.HandleRequest(ctx, req)
+	handler.HandleResponse(ctx, &http.Response{StatusCode: http.StatusOK})
+	got = handler.Stats(operation)
+	assert.NotNil(t, got.PayloadBytes)
+	assert.Equal(t, 29, *got.PayloadBytes)
 }