Modify disconnected from database per request

Author: chimame

Dockerfile

@@ -0,0 +1,5 @@
+FROM node:18.16-bullseye-slim as base
+
+RUN apt-get update && apt-get install -y clang libc++-dev libc++abi-dev build-essential
+
+WORKDIR /app

README.md

@@ -14,10 +14,12 @@ A program to set up a GraphQL server on Cloudflare Workers.
 
 ```sh
 $ docker compose up
-$ npm install
-$ npm run migrate:dev
-$ npm run start
 #=> http://localhost:8787/graphql
+
+# If you want it to work in your local environment
+# npm install
+# npm run prisma migrate deploy
+# npm run start
 ```
 
 ## License

compose.yml

@@ -1,7 +1,19 @@
 services:
+  app:
+    build:
+      context: .
+      target: base
+    entrypoint: ./scripts/docker-entrypoint.sh
+    command: npm run start
+    volumes:
+      - .:/app
+    depends_on:
+      - db
+    ports:
+      - 8787:8787
+    environment:
+      - DATABASE_URL=postgres://postgres:password@db:5432/postgres
   db:
     image: postgres:15.1-alpine3.17
-    ports:
-      - 5432:5432
     environment:
       - POSTGRES_PASSWORD=password

package-lock.json

@@ -4,7 +4,7 @@
   "private": true,
   "scripts": {
     "deploy": "wrangler publish",
-    "migrate:dev": "DATABASE_URL=postgres://postgres:password@localhost:5432/postgres prisma migrate dev",
+    "migrate:dev": "prisma migrate dev",
     "start": "wrangler dev"
   },
   "devDependencies": {
@@ -13,7 +13,7 @@
     "prisma": "^4.14.1",
     "prisma-kysely": "^1.4.1",
     "typescript": "^5.0.4",
-    "wrangler": "^3.0.0"
+    "wrangler": "^3.1.0"
   },
   "dependencies": {
     "@pothos/core": "^3.30.0",

package.json

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+npm ci
+npm run prisma migrate deploy
+
+exec "$@"

scripts/docker-entrypoint.sh

@@ -1,3 +1,4 @@
+import type { Context } from './context'
 import SchemaBuilder from '@pothos/core'
 
-export const builder = new SchemaBuilder({})
+export const builder = new SchemaBuilder<{Context: Context}>({})

src/builder.ts

@@ -5,14 +5,21 @@ import { Kysely, PostgresDialect } from 'kysely'
 // MEMO: https://developers.cloudflare.com/workers/databases/connect-to-postgres/#connection-pooling--startup
 // Cloudflare Workers seems to require a TCP connection for each connection. Therefore, using Kysely's Connection Pooling will not work properly as it will not connect when a second request is received.
 // Therefore, I try to make the connection each time.
-export const connection = () => new Kysely<DB>({
+const connection = (connectionString: string) => new Kysely<DB>({
   // Use MysqlDialect for MySQL and SqliteDialect for SQLite.
   dialect: new PostgresDialect({
     pool: new Pool({
-      host: 'localhost',
-      database: 'postgres',
-      user: 'postgres',
-      password: 'password',
+      connectionString
     }),
   }),
-})
+})
+
+export type Context = {
+  db: Kysely<DB>
+}
+
+export const createContext = (connectionString: string): Context => {
+  return {
+    db: connection(connectionString)
+  }
+}

src/context.ts

@@ -1,14 +1,12 @@
 import { builder } from '../../builder'
 import { UserType } from '../../models/User'
-import { connection } from '../../context'
 
 builder.queryFields((t) => ({
   User: t.field({
     type: UserType,
     nullable: true,
-    resolve: async () => {
-      const db = connection()
-      return await db.selectFrom('User').selectAll().executeTakeFirst()
+    resolve: async (_root, _args, ctx) => {
+      return await ctx.db.selectFrom('User').selectAll().executeTakeFirst()
     },
   }),
 }))

src/resolvers/User/query.ts

@@ -9,30 +9,22 @@
  */
 
 export interface Env {
-	// Example binding to KV. Learn more at https://developers.cloudflare.com/workers/runtime-apis/kv/
-	// MY_KV_NAMESPACE: KVNamespace;
-	//
-	// Example binding to Durable Object. Learn more at https://developers.cloudflare.com/workers/runtime-apis/durable-objects/
-	// MY_DURABLE_OBJECT: DurableObjectNamespace;
-	//
-	// Example binding to R2. Learn more at https://developers.cloudflare.com/workers/runtime-apis/r2/
-	// MY_BUCKET: R2Bucket;
-	//
-	// Example binding to a Service. Learn more at https://developers.cloudflare.com/workers/runtime-apis/service-bindings/
-	// MY_SERVICE: Fetcher;
-	//
-	// Example binding to a Queue. Learn more at https://developers.cloudflare.com/queues/javascript-apis/
-	// MY_QUEUE: Queue;
+  DATABASE_URL: string
 }
 
 import { createYoga } from 'graphql-yoga'
 import { schema } from './schema'
+import { createContext } from './context'
 
 // Create a Yoga instance with a GraphQL schema.
 const yoga = createYoga({ schema })
 
 export default {
   async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise<Response> {
-    return yoga(request, env, ctx)
+		const context = createContext(env.DATABASE_URL)
+    const response = await yoga(request, context)
+
+		await context.db.destroy()
+		return response
   },
-}
+}

src/worker.ts

@@ -4,6 +4,9 @@ compatibility_date = "2023-05-25"
 
 node_compat = true
 
+[vars]
+DATABASE_URL='postgres://postgres:password@db:5432/postgres'
+
 # # KV Namespace binding - For more information: https://developers.cloudflare.com/workers/runtime-apis/kv
 # [[kv_namespaces]]
 # binding = "MY_KV_NAMESPACE"