set fly replay header early

app/lib/db.server.ts

@@ -1,6 +1,6 @@
 import { PrismaClient, type Prisma } from "@prisma/client"
 import { IS_PROD } from "./constants"
-import { isPrimaryRegion } from "./env"
+import { IS_PRIMARY_REGION } from "./env"
 import { singleton } from "./singleton.server"
 
 const logLevel: Prisma.LogLevel[] = IS_PROD
@@ -19,7 +19,7 @@ export const prismaWrite = /* @__PURE__ */ singleton(
 export const prismaRead = /* @__PURE__ */ singleton("prisma-read", () => {
   // 5433 is the read-replica port
   let url = process.env.DATABASE_URL
-  if (!isPrimaryRegion() && IS_PROD) {
+  if (!IS_PRIMARY_REGION && IS_PROD) {
     url = url.replace(":5432", ":5433")
   }
   console.log("read replica url", url.replace(/\w+@/, "PASSWORD@"))

app/lib/env.ts

@@ -17,12 +17,6 @@ export const getServerEnv = <T extends keyof ServerEnv>(
   return process.env[key]
 }
 
-export const isPrimaryRegion = () => {
-  const FLY_REGION = getServerEnv("FLY_REGION")
-  const PRIMARY_REGION = getServerEnv("PRIMARY_REGION")
-  return Boolean(FLY_REGION && PRIMARY_REGION === FLY_REGION)
-}
-
 // Use /* @__PURE__ */ annotation to make tree-shaking work
 export const AUTH_COOKIE_NAME = /* @__PURE__ */ getServerEnv("AUTH_COOKIE_NAME")
 export const APP_NAME = /* @__PURE__ */ getCommonEnv("APP_NAME")
@@ -38,3 +32,6 @@ export const S3_ENDPOINT = /* @__PURE__ */ getServerEnv("S3_ENDPOINT")
 export const MAILGUN_APIKEY = /* @__PURE__ */ getServerEnv("MAILGUN_APIKEY")
 export const MAILGUN_DOMAIN = /* @__PURE__ */ getServerEnv("MAILGUN_DOMAIN")
 export const MAILGUN_EU = /* @__PURE__ */ getServerEnv("MAILGUN_EU")
+export const PRIMARY_REGION = /* @__PURE__ */ getServerEnv("PRIMARY_REGION")
+export const FLY_REGION = /* @__PURE__ */ getServerEnv("FLY_REGION")
+export const IS_PRIMARY_REGION = !FLY_REGION || PRIMARY_REGION === FLY_REGION

server/fly.ts

@@ -1,33 +1,7 @@
 import { type RequestHandler } from "express"
-import { IS_PROD } from "~/lib/constants"
-import { getServerEnv, isPrimaryRegion } from "~/lib/env"
-
-const PRIMARY_REGION = getServerEnv("PRIMARY_REGION")
-const FLY_REGION = getServerEnv("FLY_REGION")
+import { FLY_REGION } from "~/lib/env"
 
 export const setFlyRegionHeader: RequestHandler = (req, res, next) => {
   res.setHeader("x-fly-region", FLY_REGION || "unknown")
   next()
 }
-
-export const getReplayResponse: RequestHandler = (req, res, next) => {
-  const { method, path: pathname } = req
-
-  if (
-    !IS_PROD ||
-    ["GET", "OPTIONS", "HEAD"].includes(method) ||
-    isPrimaryRegion()
-  ) {
-    return next()
-  }
-
-  const logInfo = {
-    pathname,
-    method,
-    PRIMARY_REGION,
-    FLY_REGION,
-  }
-  console.info(`Replaying:`, logInfo)
-  res.set("fly-replay", `region=${PRIMARY_REGION}`)
-  return res.sendStatus(409)
-}

server/index.ts

@@ -1,18 +1,18 @@
 import "./globals/index"
+import http from "http"
 import path from "path"
 import express from "express"
 import compression from "compression"
 import morgan from "morgan"
 import { createRequestHandler } from "@remix-run/express"
-import { getReplayResponse, setFlyRegionHeader } from "./fly"
+import { setFlyRegionHeader } from "./fly"
 import { IS_PROD } from "~/lib/constants"
+import { FLY_REGION, IS_PRIMARY_REGION, PRIMARY_REGION } from "~/lib/env"
 
 const BUILD_DIR = path.join(process.cwd(), "build")
 
 const app = express()
 
-app.all("*", getReplayResponse)
-
 app.use(setFlyRegionHeader)
 
 if (IS_PROD) {
@@ -55,9 +55,34 @@ app.all(
 )
 const port = process.env.PORT || 3000
 
-app.listen(port, () => {
-  console.log(`Open http://localhost:${port}`)
-})
+http
+  .createServer((req, res) => {
+    const { method, url } = req
+
+    if (
+      IS_PROD &&
+      method &&
+      !["GET", "OPTIONS", "HEAD"].includes(method) &&
+      !IS_PRIMARY_REGION
+    ) {
+      const logInfo = {
+        url,
+        method,
+        PRIMARY_REGION,
+        FLY_REGION,
+      }
+      console.info(`Replaying:`, logInfo)
+      res.setHeader("fly-replay", `region=${PRIMARY_REGION}`)
+      res.statusCode = 409
+      res.end("replay")
+      return
+    }
+
+    return app(req, res)
+  })
+  .listen(port, () => {
+    console.log(`Open http://localhost:${port}`)
+  })
 
 function purgeRequireCache() {
   // purge require cache on requests for "server side HMR" this won't let