agents: fix http_client percentile calculation

p50 and p99 where flipped.

Improved `test/agents/test-grpc-metrics.mjs` to make sure we don't
regress.

Fixes: #423
PR-URL: #424
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: EHortua <55801532+EHortua@users.noreply.github.com>

Author: santigimeno

agents/otlp/src/otlp_common.cc

@@ -347,8 +347,8 @@ NSOLID_ENV_METRICS_NUMBERS(V)
               use_snake_case ? "http_client" : "httpClient",
               kNSMSecs,
               InstrumentValueType::kDouble,
-              {{ 0.5, stor.http_client99_ptile },
-               { 0.99, stor.http_client_median }},
+              {{ 0.5, stor.http_client_median },
+               { 0.99, stor.http_client99_ptile }},
               attrs);
   add_summary(metrics,
               process_start,

test/agents/test-grpc-metrics.mjs

@@ -196,6 +196,8 @@ function checkScopeMetrics(scopeMetrics) {
       if (dataPoint.quantileValues[1].value) {
         validateNumber(dataPoint.quantileValues[1].value, `${name}.quantileValues[1].value`);
       }
+
+      assert.ok(dataPoint.quantileValues[0].value >= dataPoint.quantileValues[1].value, `p99 ${name} should be >= p50 ${name}`);
     } else {
       assert.strictEqual(dataPoint.value, expectedMetric[2]);
       if (type === 'asInt') {
@@ -235,9 +237,13 @@ async function runTest({ getEnv }) {
         stdio: ['inherit', 'inherit', 'inherit', 'ipc'],
         env,
       };
-      const child = new TestClient([], opts);
+      const child = new TestClient(['-t', 'http'], opts);
       const agentId = await child.id();
-      const config = await child.config({ app: 'my_app_name', interval: 100 });
+      const config = await child.config({ app: 'my_app_name' });
+      for (let i = 0; i < 10; i++) {
+        await child.trace('http');
+      }
+
       grpcServer.once('metrics', mustCall(async () => {
         const metrics = await child.metrics();
         assert.strictEqual(config.app, 'my_app_name');
@@ -258,7 +264,6 @@ const testConfigs = [
         NODE_DEBUG_NATIVE: 'nsolid_grpc_agent',
         NSOLID_GRPC_INSECURE: 1,
         NSOLID_GRPC: `localhost:${port}`,
-        NSOLID_INTERVAL: 10000,
       };
     },
   },
@@ -268,7 +273,6 @@ const testConfigs = [
         NODE_DEBUG_NATIVE: 'nsolid_grpc_agent',
         NSOLID_GRPC_INSECURE: 1,
         NSOLID_SAAS: `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbtesting.localhost:${port}`,
-        NSOLID_INTERVAL: 10000,
       };
     },
   },