How to run postgres with docker

Often during development stages we install Postgres as a standalone package on our system. However, running it via Docker can offer many benefits & is a preferred way of running a database locally

Benefits of running postgres via docker

Running Postgres locally using Docker during development offers several advantages, including:

• Isolation: Each project can have its own isolated Postgres instance, without affecting other projects or the system's Postgres installation.
• Easy setup and teardown: Postgres instances can be quickly spun up and down as needed, without leaving behind any residue or affecting the system's configuration.
• Version control: Docker allows you to easily switch between different Postgres versions, making it simple to test and develop against different versions.
• Reduced dependencies: Docker containers package all dependencies, reducing the risk of version conflicts and making it easier to manage dependencies.
• Reproducibility: Docker containers can be easily reproduced, making it simple to set up identical environments for testing, staging, and production.

How to setup postgres using docker

• First make sure you have Docker installed on your system. You can download it from here.
• Make sure Docker is installed by running the following command docker -v in your terminal.
• Now we are going to pull and run the official postgres docker image from Postgres in our terminal.

  docker run --name my-postgres -p 5432:5432 -e POSTGRES_PASSWORD=mysecretpassword -d postgres
  

• Let us go over the command and what the flags mean :
  • --name specifies the name that you want to use for your container. my-postgres in this case.
  • --port tells on which port do you want to make the container available. On left hand side of the colon, you can specify your own port that you want the container to listen on while the port number on the right hand side forwards the requests made on the host port, i.e, the port you have mentioned to the running container. This must remain 5432.
  • -e specifies the environment variables that you want to provide to the container. Here we set the password of our postgres database by setting the following POSTGRES_PASSWORD=mysecretpassword.
  • when you run the docker run command, the current terminal session is used by the Docker process and therefore you cannot run any other commands in the same terminal session. Therefore we tell Docker to free up the terminal for running other commands by telling it to run in a detached mode. -d signifies this.
  • Finally, postgres is the name of the image that we want to run.
• Wait for some time for Docker to download and run the image.
• Once it completes check if Docker is running Postgres by running this command docker ps. This should show the running container
• Now your connection string will be available as follows to use in your applications:

  "postgres://postgres:mysecretpassword@localhost:5432"
  

  • Where postgres is the username (default), mysecretpassword is the password, localhost is the host and 5432 is the port number.
• If you have created a database then your connection string would be :

  "postgres://postgres:mysecretpassword@localhost:5432/YourDatabaseName"
  

• You can stop the running container by running docker stop my-postgres. Next time when you want to start it again you can just run docker start my-postgres
• You can also use GUI database tools such as DBeaver to connect, view & run SQL queries.