Sequelize on NodeJS/ExpressJS return an error when running CLI command db:migrate - node.js

Question

I'm following this tutorial Using PostgreSQL and Sequelize to persist our data on medium, and right now I'm stuck at the db:migrate. it's returning this error
Sequelize CLI [Node: 12.1.0, CLI: 5.4.0, ORM: 5.8.2]
Loaded configuration file "config.json".
Using environment "development".
ERROR: Error parsing url: undefined
as you can see I'm using NodeJS version 12.1.0 and Sequelize CLI version 5.4.0 and Sequelize version 5.8.2 and all of them were the latest version.
and before running sequelize db:migrate, I'm running this command first SET DATABASE_URL=postgresql://[user[:password]#][netlocation][:port][/dbname] and it does not returns any error.
but it's returning error after I ran db:migrate
I already tried to find the problem, but I can't found the answer yet.
Here is my ./Models/Index.js file.
'use strict';
require('dotenv').config();
import { readdirSync } from 'fs';
import { basename as _basename, join } from 'path';
import Sequelize from 'sequelize';
const basename = _basename(__filename);
const env = process.env.NODE_ENV || 'development';
const config = require(__dirname + '/../../config.json')[env];
const db = {};
let sequelize;
if (config.use_env_variable) {
sequelize = new Sequelize(process.env[config.use_env_variable], config);
} else {
sequelize = new Sequelize(config.database, config.username, config.password, config);
}
readdirSync(__dirname)
.filter(file => {
return (file.indexOf('.') !== 0) && (file !== basename) && (file.slice(-3) === '.js');
})
.forEach(file => {
const model = sequelize['import'](join(__dirname, file));
db[model.name] = model;
});
Object.keys(db).forEach(modelName => {
if (db[modelName].associate) {
db[modelName].associate(db);
}
});
db.sequelize = sequelize;
db.Sequelize = Sequelize;
export default db;
if you realize I just changed it to ES6 format which change some codes, but before I change it to ES6, it doesn't work either. and for all the rest of the files I following the tutorial.
Here are the files that I think have a connection:
.env
DATABASE_URL=postgres://postgres:admin#localhost:5432/test_app
.sequelizerc
const path = require('path');
module.exports = {
"config": path.resolve('./config.json'),
"models-path": path.resolve('./app/Models'),
"migrations-path": path.resolve('./migrations')
};
config.json
{
"development": {
"use_env_variable": "DATABASE_URL"
},
"test": {
"use_env_variable": "DATABASE_URL"
},
"production": {
"use_env_variable": "DATABASE_URL"
}
}
If there are some files that I haven't included yet please tell me, and please help me to fix find the solution for this problem. Thank you
OS: Windows 10

Answer 1

Basically you are unable to set environment variable DATABASE_URL successfully.
I am not a Windows guy, but this should do your job.
If you are using GitBash, then it is as simple as:
export DATABASE_URL=postgres://postgres#localhost:5432/database_name
and after that:
node_modules/.bin/sequelize db:migrate
EDIT:
I am not sure how to set this variable in gitbash and cmd.
Here is an alternate.
in config/config.json
"development": {
"username": "postgres"
"password": "postgres",
"database": "your_db_here",
"host": "127.0.0.1",
"dialect": "postgres"
},
update these variables according to your postgres db.
and run:
node_modules/.bin/sequelize db:migrate

Answer 2

You cannot fetch values at runtime inside config.json. It has to be static.
You should either use config.json or env variables or roll your own like mentioned in another answer.
To use env variables, you will eschew config.json. Instead, in models/index.js, set
if (config.use_env_variable) {
sequelize = new Sequelize(process.env[config.use_env_variable], config);
} else {
sequelize = new Sequelize(config.database, config.username, config.password, config);
}
to
sequelize = new Sequelize(process.env.DATABASE_URL)

Answer 3

AFAIK Sequelize migrations are a different beast than the normal sequelize workflow.
It is reading config/config.json when it loads - so you cannot use system environment variables - it has to be a static json file.
What I do in my projects, is having my config.js file making sure the config file is up to date with whatever settings I have.
I do this when the main program starts and also in package.json as follows:
(make sure to add npm-run-all to your package.json)
"scripts": {
"config": "node src/config.js",
"_migrate": "sequelize db:migrate",
"_migrate:status": "sequelize db:migrate:status",
"_migrate:undo": "sequelize db:migrate:undo",
"_seed": "sequelize db:seed:all",
"migrate": "npm-run-all config _migrate",
"migrate:status": "npm-run-all config _migrate:status",
"migrate:undo": "npm-run-all config _migrate:undo",
"seed": "npm-run-all config _seed"
},
config.js simply does something similar to this at the end of the file:
// Export sequelize config/config.json for easy compatibality with sequelize-cli
const filepath = path.resolve(__dirname, '../../config');
const filename = path.join(filepath, 'config.json');
fs.ensureDir(filepath)
.then(() => fs.writeFileSync(filename, JSON.stringify(sequelizeConfig, 2) + '\n'))
.catch((err) => console.error(`Failed to write config: ${err}`));
sequelizeConfig is should be the fully generated sequelize config object. You can also have a generic one like you have now, and build upon it.