fix(js): memory allocation in filtered spans

go/trace_ctx.go

@@ -128,8 +128,8 @@ func (t *TraceCtx) init(ctx context.Context, r wazero.Runtime) error {
 						f.within = append(f.within, e)
 					}
 				}
+				t.pushFunction(f)
 			}
-			t.pushFunction(f)
 			return
 		}
 

js/src/lib/adapters/datadog/formatter.ts

@@ -37,8 +37,19 @@ export class Trace {
   }
 }
 
+const allocationKey = 'allocation';
+
 export const addAllocation = (span: Span, amount: MemoryGrowAmount) => {
-  span.meta.set("allocation", amount.toString());
+  let sumAmount = amount;
+  let existingAllocation = span.meta[allocationKey];
+  if (existingAllocation) {
+    try {
+      sumAmount = parseInt(existingAllocation) + amount;
+    } catch (e) {
+      console.error(e);
+    }
+  }
+  span.meta.set(allocationKey, sumAmount.toString());
 };
 
 export class DatadogFormatter {

js/src/lib/collectors/span/mod.ts

@@ -82,6 +82,16 @@ export class SpanCollector implements Collector {
     const funcDuration = fn.duration() * 1e-3;
     const minSpanDuration = this.opts.spanFilter.minDurationMicroseconds;
     if (funcDuration < minSpanDuration) {
+      // check for memory allocations and attribute them to the parent span before filtering
+      const f = this.stack.pop();
+      if (f) {
+        fn.within.forEach((ev) => {
+          if (ev instanceof MemoryGrow) {
+            f.within.push(ev);
+          }
+        });
+        this.stack.push(f);
+      }
       return;
     }
 

js/src/lib/formatters/opentelemetry.ts

@@ -40,6 +40,7 @@ export function traceFromEvents(serviceName: string, events: ObserveEvent[]): Tr
     return trace;
 }
 
+const allocationKey = 'allocation';
 /**
  * 
  * @param trace - all spans created will be tied to this trace
@@ -53,17 +54,30 @@ function eventToSpans(trace: Trace, spans: Span[], ev: ObserveEvent, parentId?:
 
         ev.within.forEach((e) => {
             eventToSpans(trace, spans, e, span.spanId);
-        })
+        });
     }
     else if (ev instanceof MemoryGrow) {
-        const span = newSpan(trace, 'allocation', ev.start, ev.start, parentId);
-        span.attributes.push({
-            key: 'amount',
-            value: {
-                intValue: ev.amount,
-            }
-        })
-        spans.push(span);
+        const span = spans[spans.length - 1];
+        let existingIndex = -1;
+        const existing = span.attributes.find((a, i) => {
+            existingIndex = i;
+            return a.key === allocationKey
+        });
+        if (existing) {
+            span.attributes[existingIndex] = {
+                key: allocationKey,
+                value: {
+                    intValue: ev.amount + existing.value.intValue
+                }
+            };
+        } else {
+            span.attributes.push({
+                key: allocationKey,
+                value: {
+                    intValue: ev.amount,
+                }
+            });
+        }
     }
 }