perf(webapp): run unit and e2e test files in parallel on fewer shards

Runs webapp unit test files in parallel (half the available cores) and
cuts that CI matrix from 24 shards to 6. Webapp e2e files run four at a
time on one shard instead of one at a time on two.

Mono-RevId: e62ad92a646140b8f97d75ed6978d4f698e14238

Author: ericallam

.github/workflows/e2e-webapp.yml

@@ -19,8 +19,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        shardIndex: [1, 2]
-        shardTotal: [2]
+        shardIndex: [1]
+        shardTotal: [1]
     env:
       DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
       SHARD_INDEX: ${{ matrix.shardIndex }}

.github/workflows/unit-tests-webapp.yml

@@ -14,18 +14,15 @@ on:
 jobs:
   unitTests:
     name: "🧪 Unit Tests: Webapp"
-    # Webapp test throughput is limited per-machine (one docker daemon + disk absorbing
-    # all the per-file Postgres/ClickHouse container spin-up), so many machines beats
-    # few big ones - fewer/bigger (3x32) measured slower than 10x8. The 16x (vs 8x)
-    # gives the fork pool the CPU headroom the 8x runners lacked.
+    # Files run in parallel (half the cores) and share one Postgres per runner, so a
+    # few machines are enough; per-file Redis and ClickHouse boots are what's left.
     runs-on: warp-ubuntu-latest-x64-16x
     strategy:
       # one flaky shard shouldn't cancel its siblings - lets us re-run only the failed shard
       fail-fast: false
       matrix:
-        shardIndex:
-          [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
-        shardTotal: [24]
+        shardIndex: [1, 2, 3, 4, 5, 6]
+        shardTotal: [6]
     env:
       DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
       SHARD_INDEX: ${{ matrix.shardIndex }}

apps/webapp/package.json

@@ -26,7 +26,7 @@
     "db:seed:queue-metrics": "varlock run --inject vars -- tsx seed-queue-metrics.mts",
     "db:seed:webhooks": "varlock run --inject vars -- tsx seed-webhook-deliveries.ts",
     "upload:sourcemaps": "bash ./upload-sourcemaps.sh",
-    "test": "cross-env NODE_ENV=test varlock run --inject vars -- vitest --no-file-parallelism",
+    "test": "cross-env NODE_ENV=test varlock run --inject vars -- vitest",
     "test:perf": "cross-env NODE_ENV=test varlock run --inject vars -- vitest --config ./vitest.perf.config.ts --run",
     "eval:dev": "cross-env NODE_ENV=test varlock run --inject vars -- evalite watch",
     "test:bench": "cross-env NODE_ENV=test varlock run --inject vars -- vitest --config ./vitest.bench.config.ts --run"

apps/webapp/vitest.config.ts

@@ -49,6 +49,7 @@ export default defineConfig({
     ],
     globals: true,
     pool: "forks",
+    maxWorkers: "50%",
     setupFiles: ["./test/setup.ts"], // test fallbacks and isolation
   },
   // @ts-ignore

apps/webapp/vitest.e2e.config.ts

@@ -9,12 +9,11 @@ export default defineConfig({
     globals: true,
     pool: "forks",
     /**
-     * Each e2e file boots its own Docker stack (Postgres, Redis, s2-lite,
-     * MinIO) plus a webapp process. Running files in parallel boots several
-     * stacks at once and thrashes the CI runner into a timeout, so run them
-     * one at a time, matching the repo's `pnpm test --no-file-parallelism`.
+     * Each e2e file boots a webapp process plus Redis, s2-lite and MinIO, and
+     * clones its database from the shared test Postgres. A few files at a time
+     * keeps the runner from thrashing.
      */
-    fileParallelism: false,
+    maxWorkers: 4,
   },
   // @ts-ignore
   plugins: [tsconfigPaths({ projects: ["./tsconfig.json"] })],