chore(back): Adjust the folder structure for backend container, etc.

We did:

* Add Dockerfile in `back/` folder for docker container `backend`. Now it will
  build the node_modules in image. It will be helpful for those who do not have
  tool yarn and reduce the difficulty of running.
* Move source files from `back/` to `back/src`. Because Dockerfile's `COPY`
  cannot just copy directory. [More info][github-moby-dockerfile-stupid-copy].
  And that's why we also change some files with new path to those source files.
* Add `depends_on` keys in `docker-compose.yml`

[github-moby-dockerfile-stupid-copy]: moby/moby#15858

back/Dockerfile

@@ -0,0 +1,12 @@
+FROM node
+
+WORKDIR /home/node/app/
+
+COPY package.json yarn.lock ./
+RUN yarn && mkdir src
+COPY ./src/ ./src/
+
+USER node
+EXPOSE 4000
+
+CMD ["yarn", "start"]

back/make.mjs

@@ -13,7 +13,7 @@ const [_node_path, _zs_path, _this_file_path, ...argv] = process.argv;
  *****************************************************************************/
 const DB_NAME = 'acm-homepage.maria-db';
 const DB_PORT = 3306;
-const DB_DOCKERFILE_DIR = `${__dirname}/db`;
+const DB_DOCKERFILE_DIR = `${__dirname}/src/db`;
 
 /******************************************************************************
  * Main part

back/package.json

@@ -10,8 +10,9 @@
     "prettier": "^2.2.1"
   },
   "scripts": {
-    "dev": "NODE_ENV=development node main.js",
-    "format": "prettier --config ../.prettierrc -w \"?({graphql,db}/**/)*.{js,jsx,ts,tsx,json}\""
+    "dev": "NODE_ENV=development node ./src/main.js",
+    "start": "NODE_ENV=production node ./src/main.js",
+    "format": "prettier --config ../.prettierrc -w \"?(src/**/)*.{js,jsx,ts,tsx,json}\""
   },
   "type": "module"
 }

back/main.js → back/src/main.js

@@ -34,3 +34,4 @@ GraphQLServer.use(
 GraphQLServer.listen(4000, () => {
   console.log('Listening on localhost:4000...');
 });
+

docker-compose.yml

@@ -1,19 +1,17 @@
 version: "3"
 services:
   db:
-    build: ./back/db/
+    build: ./back/src/db/
   backend:
-    image: node
-    user: node
-    working_dir: /home/node/app/
-    environment:
-      - NODE_ENV=production
-    volumes:
-      - ./back/:/home/node/app/
-    command: "node main.js"
+    build: ./back/
+    depends_on:
+      - db
   nginx:
     build: ./server/
     ports:
       - 80:80
     volumes:
       - ./front/dist/:/usr/share/nginx/html/
+    depends_on:
+      - db
+      - backend