fix(trace): Crash if no attribute mapping defined

Fix #14

Author: nioc

lib/opentelemetry-node.js

@@ -284,11 +284,13 @@ function endSpan (msg, error, nodeDefinition) {
       span.setStatus({ code: SpanStatusCode.ERROR, message: error })
     }
     const localAttributes = parseAttribute(true, msg, nodeDefinition.z, nodeDefinition.type)
-    for (const [key, value] of Object.entries(localAttributes)) {
-      span.setAttribute(key, value)
-    }
-    if (_isLogging) {
-      console.log(`Local span attributes (end) for ${nodeDefinition.id}, ${nodeDefinition.type}: ${JSON.stringify(localAttributes)}`)
+    if (localAttributes !== undefined) {
+      for (const [key, value] of Object.entries(localAttributes)) {
+        span.setAttribute(key, value)
+      }
+      if (_isLogging) {
+        console.log(`Local span attributes (end) for ${nodeDefinition.id}, ${nodeDefinition.type}: ${JSON.stringify(localAttributes)}`)
+      }
     }
     span.end()
     const currentSpanCreationTimestamp = span._creationTimestamp