From 3c735a0c80f09b7fa5064f6d610d3bd617795c67 Mon Sep 17 00:00:00 2001
From: sbrooke <sbrooke@mozilla.com>
Date: Fri, 15 May 2026 17:03:05 -0400
Subject: [PATCH] feat(server): bump MAX_CONCURRENT_TASKS default from 3 to 5
 (TAB-966)

The previous default of 3 was sized against the memory math in TAB-964,
which assumed in-pod Chromium browsers (~300-400MB each). In practice the
pod connects to a remote browser pool over CDP and per-task memory in the
pod is much smaller. 5 is comfortable on the 2Gi pod limit that the
companion webservices-infra change lands.

Companion infra change pins MAX_CONCURRENT_TASKS=5 in the configmap so
deploys are explicit about the cap rather than relying on this default.

Refs: TAB-966, TAB-964
---
 packages/server/src/concurrencyGuard.test.ts | 18 ++++++++++++++++++
 packages/server/src/concurrencyGuard.ts      |  2 +-
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 packages/server/src/concurrencyGuard.test.ts

diff --git a/packages/server/src/concurrencyGuard.test.ts b/packages/server/src/concurrencyGuard.test.ts
new file mode 100644
index 00000000..6427df31
--- /dev/null
+++ b/packages/server/src/concurrencyGuard.test.ts
@@ -0,0 +1,18 @@
+import { describe, it, expect, afterEach } from "vitest";
+import { getMaxConcurrentTasks } from "./concurrencyGuard.js";
+
+describe("concurrencyGuard default cap", () => {
+  afterEach(() => {
+    delete process.env.MAX_CONCURRENT_TASKS;
+  });
+
+  it("defaults to 5 when MAX_CONCURRENT_TASKS is unset", () => {
+    delete process.env.MAX_CONCURRENT_TASKS;
+    expect(getMaxConcurrentTasks()).toBe(5);
+  });
+
+  it("honors MAX_CONCURRENT_TASKS env override", () => {
+    process.env.MAX_CONCURRENT_TASKS = "12";
+    expect(getMaxConcurrentTasks()).toBe(12);
+  });
+});
diff --git a/packages/server/src/concurrencyGuard.ts b/packages/server/src/concurrencyGuard.ts
index b744aed1..50c8d79c 100644
--- a/packages/server/src/concurrencyGuard.ts
+++ b/packages/server/src/concurrencyGuard.ts
@@ -1,4 +1,4 @@
-const getMax = () => Number(process.env.MAX_CONCURRENT_TASKS ?? 3);
+const getMax = () => Number(process.env.MAX_CONCURRENT_TASKS ?? 5);
 
 let activeTasks = 0;