Introduction

PostgreSQL is a powerful open-source relational database management system with robust features for handling large datasets and supporting complex queries. While there are many ways you can install the PostgreSQL database on your laptop directly or using a VM(Virtual machine). However dedicated resources to a VM or server can often slow down your computer. I find it convenient to use Docker, as it gives me the flexibility to quickly start and stop while reducing the load on my computer. This is very helpful when you trying to practice & learn Postgresql. How ever numerous developers use docker for development. You can start and stop PostgreSQL while storing your data persistently.

Docker, a popular containerization platform, allows you to run applications in isolated environments with ease. In this article I will try to give a step-by-step guide and walk you through the process of installing PostgreSQL on a Mac using Docker.

Prerequisites

Before you begin, ensure that you have Docker installed on your Mac. You can download and install Docker Desktop from the official Docker website.

You must launch the app to have the docker command work from a terminal.

Running PostgreSQL

Here are the steps

Launch a Terminal

We need to start with a terminal session running on our machine. You can do this from MacOS or Windows.

For MacOS, open the Terminal application on your Mac. You will find it by searching for "Terminal" in Spotlight or navigating to Applications -> Utilities -> Terminal. Click the icon to start the terminal.

For Windows, open Windows Menu. You will find the “cmd” prompt or “PowerShell”. Start either one of these,

Pull the PostgreSQL Image

In the Terminal, execute the following command to pull the latest PostgreSQL Docker image from Docker Hub:

art@arvinds-mbp# docker pull postgres

This command downloads the official PostgreSQL image to your local machine.

To verify that it was pulled down successfully, run this command:

art@arvinds-mbp# docker images

Create a Volume for Docker

Now we will create a docker volume so we can store data persistently for the PostgreSQL database. If we do not have a docker volume attached to the docker container, every time we start/stop the container the data will be lost. To create a volume, run the create volume commands for docker, as shown here. The name for the volume is pg-data.

art@arvinds-mbp# docker create volume pg-data

To check if the volume has been created, run

art@arvinds-mbp# docker volume ls

Create a PostgreSQL Container

You will need to create a docker hub account if you don’t have one already at this link. Once the image has been downloaded, create a PostgreSQL container using the below command.

art@arvinds-mbp# docker run postgres -e POSTGRES_PASSWORD=Your-Password -p 5432:5432 -v pg-data:/var/lib/postgresql/data -d postgres
Sample Output:
art@arvinds-mbp# docker run --name data-engineering-postgres -e POSTGRES_PASSWORD=secret -d postgres
3f0d664d47950f08bc188e9529ce1c0a3715b9cb6fa5ce0d4a05f753513613f1
art@arvinds-mbp#

The commands explanation: 

• docker run : Run a docker command
• postgres : name of the container for docker
• -e POSTGRES_PASSWORD : Initialize Postgres with whatevef is typed after the equals (=) sign as the password
• -p 5432:5432 : port_on_host:port_on_container (port mapping). This maps the default postgresql port for your connection.
• -v pg-data:/var/lib/postgresql/data : Map your pg-data volume you created in step 3 to Postgres container data directory /var/lib/postgresql/data
• -d postgres : initialize postgres database running detached from the terminal

Verify and Log Into PostgreSQL

Now that the PostgreSQL has been initiated let us verify if the container is up and running by using the cmd.

art@arvinds-mbp# docker ps

Sample Output :                                                                                                       
CONTAINER ID   IMAGE      COMMAND                  CREATED        STATUS         PORTS                    NAMES
a269282b057d   postgres   "docker-entrypoint.s…"   16 hours ago   Up 4 seconds   0.0.0.0:5432->5432/tcp   postgres-container

The database is ready to accept connections. Try to login by using the below command

art@arvinds-mbp# docker exec -it postgres  psql -U postgres

This will connect you to the PostgreSQL container running on docker through the psql command line.

Start using PostgreSQL

Let's try to create a database and some tables in Postgres

postgres=# create database postgresdb;
CREATE DATABASE
postgres=# \l
                                                       List of databases
    Name    |  Owner   | Encoding | Locale Provider |  Collate   |   Ctype    | ICU Locale | ICU Rules |   Access privileges   
------------+----------+----------+-----------------+------------+------------+------------+-----------+-----------------------
postgresdb | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           |
postgres   | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           |
template0  | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           | =c/postgres          +
            |          |          |                 |            |            |            |           | postgres=CTc/postgres
template1  | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           | =c/postgres          +
            |          |          |                 |            |            |            |           | postgres=CTc/postgres
(4 rows)
postgres=# \c postgresdb
You are now connected to database "postgresdb" as user "postgres".
postgresdb=# \dt
        List of relations
Schema | Name | Type  |  Owner   
--------+------+-------+----------
public | test | table | postgres
(1 row)
postgresdb=# insert into test (id,name) values  (1,'arvind');
INSERT 0 1
postgresdb=# insert into test (id,name) values  (2,'arvind2');
INSERT 0 1
postgresdb=# select * from test;
id |  name   
----+---------
  1 | arvind
  2 | arvind2
(2 rows)
postgresdb=# exit

Stop the Container and Restart It

Since we don't want to lose all our work, we have already created a dedicated volume to store all our data. We want to check this is working.

Stop the container by using the below command

art@arvinds-mbp# docker stop postgres                                                                                
postgres
art@arvinds-mbp#

 Check to confirm the container has been stopped

art@arvinds-mbp# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
art@arvinds-mbp#

Now let us start the container and use it

arvindtoorpu@nikithas-mbp ~ 
arvindtoorpu@nikithas-mbp ~ 0ocker start postgres                  
postgres

Login into PostgreSQL database (container) and check if our data is safe

art@arvinds-mbp#  docker exec -it postgres psql -U postgres
psql (16.4 (Debian 16.4-1.pgdg120+1))
Type "help" for help.
postgres=# \l
                                                       List of databases
    Name    |  Owner   | Encoding | Locale Provider |  Collate   |   Ctype    | ICU Locale | ICU Rules |   Access privileges   
------------+----------+----------+-----------------+------------+------------+------------+-----------+-----------------------
 postgresdb | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           | 
 postgres   | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           | 
 template0  | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           | =c/postgres          +
            |          |          |                 |            |            |            |           | postgres=CTc/postgres
 template1  | postgres | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           | =c/postgres          +
            |          |          |                 |            |            |            |           | postgres=CTc/postgres
(4 rows)
postgres=# \c portgresdb
You are now connected to database "portgresdb" as user "postgres".
portgresdb=# \dt
        List of relations
 Schema | Name | Type  |  Owner   
--------+------+-------+----------
 public | test | table | postgres
(1 row)
portgresdb=# select * from test;
 id |  name   
----+---------
  1 | arvind
  2 | arvind2
(2 rows)
portgresdb=#

Reference Links

• Docker docs: https://docs.docker.com/
• Docker hub: https://hub.docker.com/explore
• PostgreSQL: https://www.postgresql.org/
• PostgreSQL Tutorial: https://www.postgresqltutorial.com/postgresql-administration/