A boilerplate for GraphQL, Sequelize, PostgreSQL on Node

In this article you will look at a NodeJS app coming with an integration of GraphQL and Sequelize connected to PostgreSQL to bridge normalized, relational data (in 1-n, m-n cardinalities) to document-based representations of the data. I’m going to provide example GraphQL READ-only queries and show how they get translated into effective SQL statements through the Object Relational Mapper  Sequelize.

For a quick start, this article provides a working example on this  GH repo.

Project setup

• clone the graphql-sequelize-pg project :
• git clone **https://github.com/thomasreinecke/graphql-sequelize-pg.git- the project will be cloned into yourROJECT_HOME** directory
• on PROJECT_HOME run yarn to install the node dependencies
• install a PostgreSQL database server, make sure its running and accessible (this tutorial won’t cover this topic, however you’ll find plenty of resources on the net)
• on PROJECT_HOME edit the .envfile and apply your database settings

NODE_ENV=development
PORT=9000
DB_HOST=127.0.0.1
DB_PORT=5432
DB_DATABASE=its-my-database
DB_USERNAME=its-me
DB_PASSWORD=its-my-password
DB_SCHEMA=its-my-schema
DB_DIALECT=postgres

#nodejs #sequelize #graphql

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Buddha Community

Graphql Node JS ( Graphql Server & Client using Apollo ) # 12

Github : https://github.com/tkssharma/Graphql-

#node js #graphql node js #node #graphql server

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Learn How To Setup GraphQL Yoga Server with Node.js.

#graphql #node #graphql-node #nodejs #tutorial

Connecting Sequelize To a PostgreSQL Cluster

Prologue

In a previous post, I showed how to automate a PostgreSQL fault-tolerant cluster with Vagrant and Ansible.

This kind of setup makes our database cluster resilient to server failure and keeps the data available with no need for human interaction. But what about the apps using this database? Are they fault-tolerant too?

ORMs like Sequelize have read replication features, which allows you to define your primary and standby nodes in the database connection. But what happens if your primary node, which is responsible for write operations, is offline and your app needs to continue saving data on your database?

One way to solve this is by adding an extra layer to the system - a load balancing layer - using PostgreSQL third-party tools like pgbouncer or Pgpool-II or even a properly configured HAproxy instance. Besides the complexity brought by this method, you could also be introducing an undesired single point of failure.

Another way is using a floating IP address/virtual IP address to assign to the current primary database node, so the application knows which node it must connect to when performing write operations even if another node takes up the primary role.

We will be using Digital Ocean for server creation and floating IP assignment, but the strategy also works with other cloud providers who support floating IP.

Objectives

• connecting a NodeJS application with Sequelize to a PostgreSQL cluster in order to write to the primary node and read from standby nodes;
• create and assign a Digital Ocean Floating IP (aka FLIP) to our current primary database node;
• make repmgr interact with Digital Ocean CLI to reassign FLIP to a new primary node on promotions;
• keep this switchover transparent to the NodeJS application, so the whole system works without human help.

Pre-Requisites

• A Digital Ocean account and API token (create an account using my referral to get free credits)
• A PostgreSQL cluster with repmgr on Digital Ocean (you can grab the Ansible playbook in this tutorial to configure it or just use a cluster with streaming replication and simulate failure + manual promotion);
• NodeJS and npm installed (I’m using NodeJS v12 with npm v6);
• A PostgreSQL user with password authentication which accepts remote connections from your application host (I’ll be using postgres:123456).

Set up Your Cluster

Create Your Droplets

Create 3 droplets, preferably with the Ubuntu 20.04 operating system:

• pg1 (primary)
• pg2 (standby)
• pg3 (witness)

To make configurations run smoother, add your public SSH key when creating the droplets. You can also use the key pair I provided on GitHub for testing purposes.

If you’d like to only use 2 droplets, you can ignore the third node as it will be a PostgreSQL witness.

Note: If you use an SSH private key which is shared publicly on the internet, your cluster can get hacked.

#tutorial #devops #node.js #postgresql #node #postgres #sequelize

A boilerplate for GraphQL, Sequelize, PostgreSQL on Node

In this article you will look at a NodeJS app coming with an integration of GraphQL and Sequelize connected to PostgreSQL to bridge normalized, relational data (in 1-n, m-n cardinalities) to document-based representations of the data. I’m going to provide example GraphQL READ-only queries and show how they get translated into effective SQL statements through the Object Relational Mapper  Sequelize.

For a quick start, this article provides a working example on this  GH repo.

Project setup

• clone the graphql-sequelize-pg project :
• git clone **https://github.com/thomasreinecke/graphql-sequelize-pg.git- the project will be cloned into yourROJECT_HOME** directory
• on PROJECT_HOME run yarn to install the node dependencies
• install a PostgreSQL database server, make sure its running and accessible (this tutorial won’t cover this topic, however you’ll find plenty of resources on the net)
• on PROJECT_HOME edit the .envfile and apply your database settings

NODE_ENV=development
PORT=9000
DB_HOST=127.0.0.1
DB_PORT=5432
DB_DATABASE=its-my-database
DB_USERNAME=its-me
DB_PASSWORD=its-my-password
DB_SCHEMA=its-my-schema
DB_DIALECT=postgres

#nodejs #sequelize #graphql

Building REST API using Node, Express, Sequelize and PostgreSQL

Step by step tutorial on building REST API using Node.js, Express.js, Sequelize.js and PostgreSQL.

A comprehensive step by step tutorial on building RESTful API using Node.js, Express.js, Sequelize.js, and PostgreSQL. In this tutorial, we will show how to create a little complex table association or relationship with CRUD (Create, Read, Update, Delete) operations. So, the association or relationship will be like this diagram.

This tutorial divided into several steps:

Step #1: Create Express.js Project and Install Required Modules
Step #2: Add and Configure Sequelize.js Module and Dependencies
Step #3: Create or Generate Sequelize Models and Migrations
Step #4: Create Express Controller and Router for Classroom Model
Step #5: Create Express Controller and Router for Student Model
Step #6: Create Express Controller and Router for Lecturer Model
Step #7: Create Express Controller and Router for Course Model
Step #8: Advance Express Route and Function for Association
Step #9: Run and Test The Node, Express, Sequelize, and PostgreSQL REST API

Full article here:
https://www.djamware.com/post/5b56a6cc80aca707dd4f65a9/nodejs-expressjs-sequelizejs-and-postgresql-restful-api

Source code:
https://github.com/didinj/node-express-postgresql-sequelize.git

#api #node #express #postgresql #sequelize