From 321a63aac3723a791cb1b0aadb98880ce244e77d Mon Sep 17 00:00:00 2001
From: Jack Hsu <jack.hsu@gmail.com>
Date: Wed, 26 Feb 2025 15:46:35 -0500
Subject: [PATCH] feat(nx-dev): allow sampling rate to be configured through
 env var (#30193)

The current sample rate for Grafana Faro is the default 100% and is
currently around $200 for the month. We want to be able to make changes
to it without needing code changes. Once this PR is merged, we can just
update the env var, and then redeploy.
---
 nx-dev/nx-dev/lib/components/frontend-observability.tsx | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/nx-dev/nx-dev/lib/components/frontend-observability.tsx b/nx-dev/nx-dev/lib/components/frontend-observability.tsx
index fd2e1902cf..de7f2da923 100644
--- a/nx-dev/nx-dev/lib/components/frontend-observability.tsx
+++ b/nx-dev/nx-dev/lib/components/frontend-observability.tsx
@@ -2,6 +2,12 @@
 import { useEffect, useRef } from 'react';
 import { getWebInstrumentations, initializeFaro } from '@grafana/faro-web-sdk';
 
+const DEFAULT_SAMPLE_RATE = 0.5;
+let samplingRate = process.env.NEXT_PUBLIC_FARO_SAMPLING_RATE
+  ? parseFloat(process.env.NEXT_PUBLIC_FARO_SAMPLING_RATE)
+  : DEFAULT_SAMPLE_RATE;
+if (isNaN(samplingRate) || samplingRate > 1) samplingRate = DEFAULT_SAMPLE_RATE;
+
 export function FrontendObservability() {
   const initialized = useRef(false);
   useEffect(() => {
@@ -24,6 +30,9 @@ export function FrontendObservability() {
         version,
         environment,
       },
+      sessionTracking: {
+        samplingRate,
+      },
       instrumentations: [...getWebInstrumentations()],
     });
   }, []);