Truncate derived transaction names

solarwinds · Jun 17, 2024 · 78316fa · 78316fa
1 parent c7b7d7e
commit 78316fa
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Showing 2 changed files with 45 additions and 28 deletions.
diff --git a/internal/txn/txn.go b/internal/txn/txn.go
@@ -35,37 +35,37 @@ func GetTransactionName(span sdktrace.ReadOnlySpan) string {
 }
 
 // deriveTransactionName returns transaction name from given span name and attributes, falling back to "unknown"
-func deriveTransactionName(name string, attrs []attribute.KeyValue) (txnName string) {
-	if txnName = config.GetTransactionName(); txnName != "" {
-		return
-	}
-
-	var httpRoute, httpUrl = "", ""
-	for _, attr := range attrs {
-		if attr.Key == semconv.HTTPRouteKey {
-			httpRoute = attr.Value.AsString()
-		} else if attr.Key == semconv.HTTPURLKey {
-			httpUrl = attr.Value.AsString()
+func deriveTransactionName(name string, attrs []attribute.KeyValue) string {
+	txnName := config.GetTransactionName()
+	if txnName == "" {
+		var httpRoute, httpUrl = "", ""
+		for _, attr := range attrs {
+			if attr.Key == semconv.HTTPRouteKey {
+				httpRoute = attr.Value.AsString()
+			} else if attr.Key == semconv.HTTPURLKey {
+				httpUrl = attr.Value.AsString()
+			}
 		}
-	}
 
-	if httpRoute != "" {
-		txnName = httpRoute
-	} else if name != "" {
-		txnName = name
-	}
-	if httpUrl != "" && strings.TrimSpace(txnName) == "" {
-		parsed, err := url.Parse(httpUrl)
-		if err != nil {
-			// We can't import internal logger in the util package, so we default to "log". However, this should be
-			// infrequent.
-			log.Println("could not parse URL from span", httpUrl)
-		} else {
-			// Clear user/password
-			parsed.User = nil
-			txnName = parsed.String()
+		if httpRoute != "" {
+			txnName = httpRoute
+		} else if name != "" {
+			txnName = name
+		}
+		if httpUrl != "" && strings.TrimSpace(txnName) == "" {
+			parsed, err := url.Parse(httpUrl)
+			if err != nil {
+				// We can't import internal logger in the util package, so we default to "log". However, this should be
+				// infrequent.
+				log.Println("could not parse URL from span", httpUrl)
+			} else {
+				// Clear user/password
+				parsed.User = nil
+				txnName = parsed.String()
+			}
 		}
 	}
+
 	txnName = strings.TrimSpace(txnName)
 	if txnName == "" {
 		txnName = "unknown"
@@ -74,5 +74,5 @@ func deriveTransactionName(name string, attrs []attribute.KeyValue) (txnName str
 	if len(txnName) > 255 {
 		txnName = txnName[:255]
 	}
-	return
+	return txnName
 }
diff --git a/internal/txn/txn_test.go b/internal/txn/txn_test.go
@@ -111,3 +111,20 @@ func TestDeriveTxnFromEnv(t *testing.T) {
 	require.Equal(t, envTxn, config.GetTransactionName())
 	require.Equal(t, envTxn, deriveTransactionName(name, attrs))
 }
+func TestDeriveTxnFromEnvTruncated(t *testing.T) {
+	envTxn := strings.Repeat("a", 1024)
+	expected := strings.Repeat("a", 255)
+	name := "span name"
+	var attrs []attribute.KeyValue
+	require.NoError(t, os.Setenv("SW_APM_TRANSACTION_NAME", envTxn))
+	require.NoError(t, os.Setenv("AWS_LAMBDA_FUNCTION_NAME", "foo"))
+	require.NoError(t, os.Setenv("LAMBDA_TASK_ROOT", "bar"))
+	defer func() {
+		_ = os.Unsetenv("SW_APM_TRANSACTION_NAME")
+		_ = os.Unsetenv("AWS_LAMBDA_FUNCTION_NAME")
+		_ = os.Unsetenv("LAMBDA_TASK_ROOT")
+	}()
+	config.Load()
+	require.Equal(t, envTxn, config.GetTransactionName())
+	require.Equal(t, expected, deriveTransactionName(name, attrs))
+}