From c5f3f6e03d44990404f11fac381c12e35db26da3 Mon Sep 17 00:00:00 2001
From: Vasilis Xouris <vasileios.xouris@uniswap.org>
Date: Fri, 9 Aug 2024 21:16:49 -0700
Subject: [PATCH] fix(alarm): exclude very low volume chains from 4xx alarm (no
 route)

---
 bin/stacks/routing-api-stack.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/bin/stacks/routing-api-stack.ts b/bin/stacks/routing-api-stack.ts
index 3cdccae39..35d5060e5 100644
--- a/bin/stacks/routing-api-stack.ts
+++ b/bin/stacks/routing-api-stack.ts
@@ -401,8 +401,10 @@ export class RoutingAPIStack extends cdk.Stack {
         return
       }
       const alarmName = `RoutingAPI-SEV3-4XXAlarm-ChainId: ${chainId.toString()}`
+      // We only want to alert if the volume is high enough over default period (5m) for 4xx errors (no route).
+      const invocationsThreshold = 500;
       const metric = new MathExpression({
-        expression: '100*(response400/invocations)',
+        expression: `IF(invocations > ${invocationsThreshold}, 100*(response400/invocations), 0)`,
         usingMetrics: {
           invocations: new aws_cloudwatch.Metric({
             namespace: 'Uniswap',