[recnet-api] Create README.md

apps/recnet-api/.env.sample

@@ -0,0 +1,13 @@
+# Usage: cp .env.sample .env
+
+# Database
+export RDS_HOSTNAME=localhost
+export RDS_PORT=5432
+export RDS_DB_NAME=postgres
+export RDS_USERNAME=postgres
+export RDS_PASSWORD=admin
+
+# Prisma
+export DB_MIGRATE=true
+export PRISMA_SCHEMA=./apps/recnet-api/prisma/schema.prisma
+export PRISMA_DATABASE_URL="postgresql://postgres:admin@localhost:5432/postgres"

apps/recnet-api/README.md

@@ -0,0 +1,84 @@
+# Recnet-api
+
+Recnet-api is a backend API service for [Recnet](https://www.recnet.io/). Powered by Node.js and [NestJS](https://nestjs.com/), it offers scalable solutions for paper recommendation, news feed system and academic social media network.
+
+## Requirements
+
+- node >= 18
+- PostgreSQL 16
+
+## Documentation
+- [Notion](https://www.notion.so/RecNet-f8440e23b4e54af4a9636e84ed101815)
+- Swagger API Doc
+  - [dev](https://dev-api.recnet.io/api)
+  - prod
+
+## Local Development
+
+### Installation
+```bash
+pnpm install
+```
+
+### Set up a local DB
+1. Use docker to create a PostgreSQL container.
+```bash
+# create and start
+docker create --name recnet-postgres -p 5432:5432 -e POSTGRES_PASSWORD=admin postgres:16.2
+docker start recnet-postgres
+
+# stop and remove
+docker stop recnet-postgres
+docker rm recnet-postgres
+```
+
+2. Run migration
+```bash
+nx prisma deploy recnet-api
+```
+
+### Prepare environment variable
+1. Copy from sample file
+```bash
+cp apps/recnet-api/.env.sample apps/recnet-api/.env
+```
+2. Modify environment variable
+3. Source the .env file
+```bash
+source apps/recnet-api/.env
+```
+
+### Generate prisma client
+```bash
+nx prisma:generate recnet-api
+```
+
+### Run the server
+```bash
+nx serve recnet-api
+```
+
+## DB Migration
+### How to generate migration files?
+1. Prepare a local database. Same as [here](#set-up-a-local-db).
+2. Modify `apps/recnet-api/prisma/prisma.schema`
+3. Run migration script. The migration script will create a directory under `apps/recnet-api/prisma/migrations` with `migration.sql` and `down.sql`.
+```bash
+nx prisma:migrate recnet-api {migration_name}
+```
+
+### How does the migration script been deployed to dev or production environment?
+If the environment variable `DB_MIGRATION=true`, the migration will be deployed when the server is up. It is executed by `prisma.connection.provider.ts`.
+
+## Environment and Deployment
+We currently maintain two environment - dev and prod. All of the services are deployed to AWS Elastic Beanstalk.
+
+### API host
+- dev: https://dev-api.recnet.io/
+- prod: https://api.recnet.io/
+
+### Deployment
+We utilize AWS CodePipeline to build up the CI/CD for the services. Whenever the designated branch updates, the pipeline will deploy the code on that branch to the corresponding environment.
+
+- dev branch: recnet-api-dev
+- prod branch: master

apps/recnet-api/scripts/dbMigrate.sh

@@ -18,7 +18,11 @@ perform_migration_down() {
 
 move_down_sql_file() {
     DIRECTORY=$(find $PRISMA_MIGRATIONS_DIR -type d -name "*$MIGRATION_NAME*" | tail -n 1)
-    mv down.sql $DIRECTORY/down.sql
+    if [ -s "down.sql" ]; then
+        mv down.sql $DIRECTORY/down.sql
+    else
+        rm down.sql
+    fi
 }
 
 echo "Migrating database to $MIGRATION_NAME"