refactor(cloud-function): extract REVIEW_ROUTING + CACHE_DISABLED

.github/workflows/review-deploy.yml

@@ -88,7 +88,8 @@ jobs:
             --timeout=120s \
             --run-service-account=run-mdn-review-functions@${{ secrets.GCP_PROJECT_NAME }}.iam.gserviceaccount.com \
             --set-env-vars="IGNORED_ROUTES=" \
-            --set-env-vars="WILDCARD_ENABLED=true" \
+            --set-env-vars="REVIEW_ROUTING=true" \
+            --set-env-vars="CACHE_DISABLED=true" \
             --set-env-vars="SOURCE_CONTENT=https://storage.googleapis.com/${{ vars.GCP_BUCKET_NAME }}/" \
             --set-env-vars="SENTRY_DSN=${{ secrets.SENTRY_DSN_CLOUD_FUNCTION }}" \
             --set-env-vars="SENTRY_ENVIRONMENT=review" \

cloud-function/README.md

@@ -40,9 +40,12 @@ The function uses the following environment variables:
   client build is served.
 - `SOURCE_API` (default: `"https://developer.allizom.org/"`) - The URL at which
   the API is served.
-- `WILDCARD_ENABLED` (default: `false`) - If enabled, accepts any `Host` header
-  value, and uses the leftmost subdomain to route into a subdirectory of
-  `SOURCE_CONTENT`.
+- `REVIEW_ROUTING` (default: `false`) - If enabled, accepts any `Host` header
+  value, uses the leftmost subdomain to route into a subdirectory of
+  `SOURCE_CONTENT`, and falls back to production for missing assets.
+- `CACHE_DISABLED` (default: `false`) - If enabled, disables response caching
+  (`Cache-Control: no-store` for non-hashed 200 responses, and skips the
+  in-memory 404 cache).
 
 The placement handler uses the following environment variables:
 

cloud-function/src/env.js

@@ -103,8 +103,12 @@ export const BSA_ZONE_KEYS = Object.fromEntries(
   (process.env["BSA_ZONE_KEYS"] ?? "").split(";").map((k) => k.split(":"))
 );
 
-export const WILDCARD_ENABLED = Boolean(
-  JSON.parse(process.env["WILDCARD_ENABLED"] || "false")
+export const REVIEW_ROUTING = Boolean(
+  JSON.parse(process.env["REVIEW_ROUTING"] || "false")
+);
+
+export const CACHE_DISABLED = Boolean(
+  JSON.parse(process.env["CACHE_DISABLED"] || "false")
 );
 
 // HTTPS.

cloud-function/src/handlers/proxy-content.js

@@ -5,7 +5,7 @@ import {
 } from "http-proxy-middleware";
 
 import { withContentResponseHeaders } from "../headers.js";
-import { Source, sourceUri, WILDCARD_ENABLED } from "../env.js";
+import { CACHE_DISABLED, REVIEW_ROUTING, Source, sourceUri } from "../env.js";
 import { PROXY_TIMEOUT } from "../constants.js";
 import { isLiveSampleURL } from "../utils.js";
 import { ACTIVE_LOCALES } from "../internal/constants/index.js";
@@ -22,7 +22,7 @@ const target = sourceUri(Source.content);
 const router = (req) => {
   let actualTarget = target;
 
-  if (WILDCARD_ENABLED) {
+  if (REVIEW_ROUTING) {
     const { host } = req.headers;
 
     if (typeof host === "string") {
@@ -129,7 +129,7 @@ export const proxyContentAssets = createContentProxyMiddleware(
       return Buffer.from(await enUsAsset.arrayBuffer());
     }
 
-    if (WILDCARD_ENABLED) {
+    if (REVIEW_ROUTING) {
       // Fallback to prod.
       const prodUrl = new URL(req.url ?? "", "https://developer.mozilla.org/");
       res.statusCode = 303;
@@ -154,7 +154,7 @@ async function get404ForLocale(locale) {
   } else {
     const response = await fetch(`${target}${locale}/404/index.html`);
     notFoundBuffer = response.arrayBuffer();
-    if (!WILDCARD_ENABLED) {
+    if (!CACHE_DISABLED) {
       if (response.ok) {
         notFoundBufferCache[locale] = notFoundBuffer;
       } else {

cloud-function/src/headers.js

@@ -2,7 +2,7 @@
 
 import { CSP_VALUE } from "./internal/constants/index.js";
 import { isLiveSampleURL } from "./utils.js";
-import { WILDCARD_ENABLED } from "./env.js";
+import { CACHE_DISABLED } from "./env.js";
 
 const HASHED_MAX_AGE = 60 * 60 * 24 * 365;
 const DEFAULT_MAX_AGE = 60 * 60;
@@ -72,7 +72,7 @@ function getCacheControl(statusCode, url) {
   }
 
   if (200 <= statusCode && statusCode < 300) {
-    if (WILDCARD_ENABLED && !HASHED_REGEX.test(url)) {
+    if (CACHE_DISABLED && !HASHED_REGEX.test(url)) {
       return NO_CACHE_VALUE;
     }
 

cloud-function/src/middlewares/require-origin.js

@@ -1,17 +1,17 @@
 /** @import { NextFunction, Request, Response } from "express" */
 /** @import { OriginType } from "../env.js" */
 
-import { WILDCARD_ENABLED, getOriginFromRequest } from "../env.js";
+import { REVIEW_ROUTING, getOriginFromRequest } from "../env.js";
 
 /**
  * Creates a middleware that requires the request to come from one of the expected origins.
- * Returns 404 if the origin doesn't match (unless WILDCARD_ENABLED is true).
+ * Returns 404 if the origin doesn't match (unless REVIEW_ROUTING is true).
  * @param {...OriginType} expectedOrigins - The allowed origin types
  * @returns {(req: Request, res: Response, next: NextFunction) => void} Express middleware function
  */
 export function requireOrigin(...expectedOrigins) {
   return async (req, res, next) => {
-    if (WILDCARD_ENABLED) {
+    if (REVIEW_ROUTING) {
       return next();
     }