chore: import upstream snapshot with attribution

apps/webapp/test/otlpMetrics.helpers.ts

@@ -0,0 +1,67 @@
+import type { createInMemoryMetrics } from "./utils/tracing";
+
+type MetricsHelper = ReturnType<typeof createInMemoryMetrics>;
+
+// With cumulative temporality the latest export carries running totals for every instrument.
+export async function latestMetrics(helper: MetricsHelper) {
+  const all = await helper.getMetrics();
+  return all[all.length - 1];
+}
+
+export function findMetric(resourceMetrics: any, name: string): any | undefined {
+  if (!resourceMetrics) return undefined;
+  for (const scopeMetrics of resourceMetrics.scopeMetrics) {
+    for (const metric of scopeMetrics.metrics) {
+      if (metric.descriptor.name === name) return metric;
+    }
+  }
+  return undefined;
+}
+
+function pointValue(dp: any): number {
+  const value = dp.value;
+  if (typeof value === "number") return value;
+  // Histogram / ExponentialHistogram data point
+  return value?.sum ?? 0;
+}
+
+function matches(dp: any, attrs?: Record<string, string>): boolean {
+  if (!attrs) return true;
+  return Object.entries(attrs).every(([k, v]) => String(dp.attributes?.[k]) === v);
+}
+
+export function metricSum(
+  resourceMetrics: any,
+  name: string,
+  attrs?: Record<string, string>
+): number {
+  const metric = findMetric(resourceMetrics, name);
+  if (!metric) return 0;
+  return metric.dataPoints
+    .filter((dp: any) => matches(dp, attrs))
+    .reduce((acc: number, dp: any) => acc + pointValue(dp), 0);
+}
+
+export function histogramCount(
+  resourceMetrics: any,
+  name: string,
+  attrs?: Record<string, string>
+): number {
+  const metric = findMetric(resourceMetrics, name);
+  if (!metric) return 0;
+  return metric.dataPoints
+    .filter((dp: any) => matches(dp, attrs))
+    .reduce((acc: number, dp: any) => acc + (dp.value?.count ?? 0), 0);
+}
+
+export function gaugeValue(
+  resourceMetrics: any,
+  name: string,
+  attrs?: Record<string, string>
+): number | undefined {
+  const metric = findMetric(resourceMetrics, name);
+  if (!metric) return undefined;
+  const points = metric.dataPoints.filter((dp: any) => matches(dp, attrs));
+  if (points.length === 0) return undefined;
+  return Math.max(...points.map((dp: any) => pointValue(dp)));
+}