From e175c643be04d851c0ee3b454ac9c3128d0f5e3c Mon Sep 17 00:00:00 2001
From: Junaid Ahmed <me@junaid.guru>
Date: Tue, 16 Jun 2026 23:36:42 +0100
Subject: [PATCH] perf(personal-site-2026): tighten startup probe to cut cold
 start
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The cloud-run module's startup probe (initial_delay 5s, period 10s) held every scale-from-zero instance "not ready" for a fixed ~5s, even though the compiled Deno binary serves in ~1.7s — pinning cold starts at ~5.1s.

Expose the probe schedule as a module variable defaulting to the existing 5/10/3/3 values (no change for any other caller), and override it for personal-site-2026 to 0/1/10/1 so a ready instance is detected in ~1s.
---
 terraform/apps/personal-site-2026.tf     | 11 +++++++++++
 terraform/modules/cloud-run/main.tf      |  8 ++++----
 terraform/modules/cloud-run/variables.tf | 16 ++++++++++++++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/terraform/apps/personal-site-2026.tf b/terraform/apps/personal-site-2026.tf
index 086552a..8c9d9b1 100644
--- a/terraform/apps/personal-site-2026.tf
+++ b/terraform/apps/personal-site-2026.tf
@@ -46,6 +46,17 @@ module "personal_site_cloud_run" {
   max_instances = 1
   health_path   = "/"
 
+  # The compiled Deno binary is serving in ~1.7s, yet the module's default probe
+  # (initial_delay 5s, period 10s) holds the instance "not ready" for a fixed 5s,
+  # pinning every scale-from-zero request at ~5.1s. Probe from t=0 every 1s so a
+  # ready instance is picked up in ~1s; failure_threshold keeps a 10s boot budget.
+  startup_probe = {
+    initial_delay_seconds = 0
+    period_seconds        = 1
+    failure_threshold     = 10
+    timeout_seconds       = 1
+  }
+
   depends_on = [module.personal_site_identity]
 }
 
diff --git a/terraform/modules/cloud-run/main.tf b/terraform/modules/cloud-run/main.tf
index b446d0c..88053ac 100644
--- a/terraform/modules/cloud-run/main.tf
+++ b/terraform/modules/cloud-run/main.tf
@@ -42,10 +42,10 @@ resource "google_cloud_run_v2_service" "default" {
         http_get {
           path = var.health_path
         }
-        initial_delay_seconds = 5
-        period_seconds        = 10
-        failure_threshold     = 3
-        timeout_seconds       = 3
+        initial_delay_seconds = var.startup_probe.initial_delay_seconds
+        period_seconds        = var.startup_probe.period_seconds
+        failure_threshold     = var.startup_probe.failure_threshold
+        timeout_seconds       = var.startup_probe.timeout_seconds
       }
 
       liveness_probe {
diff --git a/terraform/modules/cloud-run/variables.tf b/terraform/modules/cloud-run/variables.tf
index fdb99fc..8ad621d 100644
--- a/terraform/modules/cloud-run/variables.tf
+++ b/terraform/modules/cloud-run/variables.tf
@@ -55,6 +55,22 @@ variable "health_path" {
   default     = "/api/health"
 }
 
+variable "startup_probe" {
+  description = "Startup-probe schedule. Defaults preserve the original behaviour; override per-app to tune cold-start readiness."
+  type = object({
+    initial_delay_seconds = number
+    period_seconds        = number
+    failure_threshold     = number
+    timeout_seconds       = number
+  })
+  default = {
+    initial_delay_seconds = 5
+    period_seconds        = 10
+    failure_threshold     = 3
+    timeout_seconds       = 3
+  }
+}
+
 variable "allow_unauthenticated" {
   description = "Allow public access to the service"
   type        = bool