Fix flaky art upload E2E test by verifying MinIO bucket

The test failed intermittently in CI with a 500 from POST /art/new.data:
the sendou bucket was missing for the whole run, so the upload threw
NoSuchBucket. art.spec.ts is the only e2e test that writes to S3, which
is why it was the only casualty.

.github/workflows/e2e-tests.yml

@@ -23,10 +23,13 @@ jobs:
       - name: Start MinIO
         run: docker compose up -d minio
 
+      # the bucket, not the health endpoint: MinIO answers health/live while it is still
+      # bootstrapping, so a run whose bucket never got created would only surface much later
+      # as a 500 in the one test that uploads an image
       - name: Wait for MinIO to be ready
         run: |
           for i in {1..30}; do
-            if curl -sf http://127.0.0.1:9000/minio/health/live; then
+            if curl -sf -o /dev/null http://127.0.0.1:9000/sendou/; then
               echo "MinIO is ready"
               exit 0
             fi

compose.yaml

@@ -12,9 +12,9 @@ services:
         isAlive() { curl -sf http://127.0.0.1:9000/minio/health/live; }    # check if Minio is alive
         minio $$0 "$$@" --quiet & echo $$! > /tmp/minio.pid                # start Minio in the background
         while ! isAlive; do sleep 0.1; done                                # wait until Minio is alive
-        mc alias set minio http://127.0.0.1:9000 minio-user minio-password # setup Minio client
-        mc mb minio/sendou || true                                         # create a test bucket
-        mc anonymous set public minio/sendou                               # make the test bucket public
+        until mc alias set minio http://127.0.0.1:9000 minio-user minio-password; do sleep 0.5; done # setup Minio client (health/live can answer before credentials are accepted)
+        until mc mb --ignore-existing minio/sendou; do sleep 0.5; done      # create a test bucket
+        until mc anonymous set public minio/sendou; do sleep 0.5; done      # make the test bucket public
         kill -s INT $$(cat /tmp/minio.pid) && rm /tmp/minio.pid            # stop Minio
         while isAlive; do sleep 0.1; done                                  # wait until Minio is stopped
         exec minio $$0 "$$@"                                               # start Minio in the foreground

e2e/global-setup.ts

@@ -7,6 +7,9 @@ import { E2E_BASE_PORT, e2eWorkerPort } from "./helpers/playwright";
 const DEBUG = process.env.E2E_DEBUG === "true";
 const SERVER_PROCESSES: ChildProcess[] = [];
 const MINIO_MARKER_FILE = ".e2e-minio-started";
+const STORAGE_BUCKET = "sendou";
+/** Anonymously listable only once the bucket exists and its public policy is set. */
+const MINIO_BUCKET_URL = `http://127.0.0.1:9000/${STORAGE_BUCKET}/`;
 const BUILD_MARKER_FILE = ".e2e-build-marker";
 const BUILD_INPUTS = [
 	"app",
@@ -21,16 +24,26 @@ declare global {
 	var __E2E_SERVERS__: ChildProcess[];
 }
 
+/**
+ * Whether the image storage is usable, which takes more than MinIO answering its health check:
+ * the container bootstraps the bucket only after startup, and a run whose bucket never got created
+ * would otherwise fail deep inside the one test that uploads an image (`art.spec.ts`) with an
+ * opaque 500.
+ */
+async function isMinioBucketReady(): Promise<boolean> {
+	try {
+		const response = await fetch(MINIO_BUCKET_URL);
+		return response.ok;
+	} catch {
+		return false;
+	}
+}
+
 async function waitForMinio(timeout = 60000): Promise<boolean> {
 	const start = Date.now();
 	while (Date.now() - start < timeout) {
-		try {
-			const response = await fetch("http://127.0.0.1:9000/minio/health/live");
-			if (response.ok) {
-				return true;
-			}
-		} catch {
-			// MinIO not ready yet
+		if (await isMinioBucketReady()) {
+			return true;
 		}
 		await new Promise((resolve) => setTimeout(resolve, 1000));
 	}
@@ -39,15 +52,10 @@ async function waitForMinio(timeout = 60000): Promise<boolean> {
 
 async function ensureMinioRunning(): Promise<boolean> {
 	// Check if MinIO is already running
-	try {
-		const response = await fetch("http://127.0.0.1:9000/minio/health/live");
-		if (response.ok) {
-			// biome-ignore lint/suspicious/noConsole: CLI script output
-			console.log("MinIO is already running");
-			return false;
-		}
-	} catch {
-		// MinIO not running, we need to start it
+	if (await isMinioBucketReady()) {
+		// biome-ignore lint/suspicious/noConsole: CLI script output
+		console.log("MinIO is already running");
+		return false;
 	}
 
 	// biome-ignore lint/suspicious/noConsole: CLI script output
@@ -56,7 +64,9 @@ async function ensureMinioRunning(): Promise<boolean> {
 
 	const isReady = await waitForMinio();
 	if (!isReady) {
-		throw new Error("MinIO failed to start within timeout");
+		throw new Error(
+			`MinIO did not become usable within timeout (${MINIO_BUCKET_URL} never answered OK). If MinIO is running, its "${STORAGE_BUCKET}" bucket is missing or not public — recreate the container with "docker compose up -d --force-recreate minio".`,
+		);
 	}
 
 	// biome-ignore lint/suspicious/noConsole: CLI script output
@@ -225,7 +235,7 @@ async function globalSetup(config: FullConfig) {
 					STORAGE_ACCESS_KEY: "minio-user",
 					STORAGE_SECRET: "minio-password",
 					STORAGE_REGION: "us-east-1",
-					STORAGE_BUCKET: "sendou",
+					STORAGE_BUCKET,
 					// no system messages to a shared skalop instance (see build env above)
 					SKALOP_SYSTEM_MESSAGE_URL: "",
 					SKALOP_TOKEN: "",