如何使用 heroku 和 nodejs 设置 postgresql 配置？

Question

This is my first time try to host nodeJS application - built with hapi.js, typeorm and postgresql - on heroku. I've create two apps on heroku - for "staging" (server-staging) and "production" (server-prod) - that using same code but will use different configuration. Why different configuration? because each application on heroku will use different postgres credential, as it's attached as an add-ons.

objective

My objective/main question is How and where I have to set the database config for my application?

I use .env file (which I ignore in .gitignore - I don't want to put the credential in my repo ) to connect the application to my local database. Here is how the .env looks like:

HOST=localhost
PORT=3001

TYPEORM_CONNECTION=postgres
TYPEORM_HOST=localhost
TYPEORM_USERNAME=postgres
TYPEORM_PASSWORD=password
TYPEORM_DATABASE=database
TYPEORM_PORT=5432
TYPEORM_SYNCHRONIZE=true
TYPEORM_LOGGING=false

In the application, I never do/write code such process.env.TYPEORM_USERNAME since its done by the typeorm node_modules. What I do to start the connection is by doing this:

const server = new Hapi.Server({
    port: process.env.PORT,
    host: process.env.HOST,
    routes: {
      cors: Cors,
    },
  });

  await server.register(Plugins);

  server.route(Router);

  await createConnection();
  await server.start();

And my application automatically connected to the specified database as defined in the .env . Now, in heroku, the credential is lies here:

All information lies there, but, [Q1] I don't know how to tell my application (of course, without store the credential in my code/repo) that I have to use the config as defined in above picture? Also, as stated in above image, "Heroku rotates credentials periodically and updates applications where this database is attached.". Does it means the credentials will changed periodically? [Q2] If yes, is there any way to make my application auto recognise the new credential?

Sorry if my explanation make confused. If you did not understand what I am trying to achieve, please ask things that you don't understand, so I can fix/update my question to make it understandable.

Anyway, I found this example first-example and second-example . But, they are using process.env.DATABASE_URL , which contain credential. I think, it means that they not ignore their .env file in their repo?

*) Note: Q1 means Question 1, and so for the rest

Answer 1

Write a ormconfig.js file in the root of your repo. This way you can access the environment variables like the url provided from heroku and you don't have credentials in your repo.

 require('dotenv').config(); module.exports = [ { name: 'default', type: 'postgres', url: process.env.DATABASE_URL, synchronize: false, logging: false, entities: ['dist/entities/*.*'], migrations: ['dist/database/migrations/**/*.js'], subscribers: ['dist/database/subscribers/**/*.js'], cli: { entitiesDir: 'dist/entities', migrationsDir: 'dist/database/migrations', subscribersDir: 'dist/database/subscribers', }, }, { name: 'development', type: 'postgres', host: process.env.POSTGRES_HOST, port: process.env.POSTGRES_PORT, username: process.env.POSTGRES_USER, password: process.env.POSTGRES_PASSWORD, database: process.env.POSTGRES_DB, synchronize: true, logging: true, entities: ['src/entities/*.*'], migrations: ['src/database/migrations/**/*.ts'], subscribers: ['src/database/subscribers/**/*.ts'], cli: { entitiesDir: 'src/entities', migrationsDir: 'src/database/migrations', subscribersDir: 'src/database/subscribers', }, }, ];

With this configuration you can then get a specific configuration in javascript/typescript:

let connectionOptions: ConnectionOptions;

if(process.env.NODE_ENV ==='development') { 
  connectionOptions = await getConnectionOptions("development");
} else {
  connectionOptions = await getConnectionOptions("default");
}
await createConnection(connectionOptions);