Blogdp438

These are my notes for running Postgres in a Docker container for use with a local Django or Rails development server running on the host machine (not in Docker). Running in Docker allows keeping my database environment isolated from the rest of my system and allows running multiple versions and instances. (I previously had a problem where Homebrew upgraded Postgres when I didn't expect it to and my existing database became incompatible. Admittedly, I didn't know Homebrew well, but it was frustrating.) Disadvantages of Docker are it's another layer of abstraction to learn and interact with. We use Docker extensively at work, so from a mental overhead point of view, it's something I wanted to learn anyways. Currently I use the Homebrew Postgres for work, and Postgres in Docker for personal projects. I also wrote some notes on Postgres and Homebrew here.

$ psql -U postgres postgres=# alter user postgres with password 'NEWPASSWORD'; postgresl=# q Reset the PostgreSQL password. If you don’t remember your PostgreSQL database password, you can follow the steps below to reset it to a new value: Change the authentication method in the PostgreSQL configuration file pghba.conf from md5 to trust. In Terminal run the following command to install PostgreSQL on Mac using Homebrew. $ brew install postgres We can check the version of PostgreSQL using the psql command. $ psql -version psql (PostgreSQL) 11.5 Start PostgreSQL. To start PostgreSQL run the following command in the Terminal. $ brew services start postgres We will get a similar.

Install Docker¶

Install Docker for Mac: https://docs.docker.com/docker-for-mac/install/.

Alternatively, you can install Docker using Homebrew: brew install homebrew/cask/docker

OPTION 1: Run Postgres using a single Docker command ¶

• uses the official docker postgres 13 image
• uses a named volume, my_dbdata, to store postgres data
• exposes port 54320 to the host using -p
• sets the container name to my_postgres
• uses the -d flag to run in the background
• sets the postgres superuser password to 'my_password' using -e and the POSTGRES_PASSWORD environment variable.

OPTION 2: Run Postgres using Docker Compose¶

Mac Postgresql Client

Create a new file docker-compose.yml:

• uses docker compose file version 3
• sets up a service named 'db' (this name can be used with docker-compose commands)
• uses the postgres:13 image from hub.docker.com using the image key
• creates a container named 'my_postgres' using the container_name key
• sets the postgres superuser password to 'my_password' using the environment key and the POSTGRES_PASSWORD environment variable
• connects port 5432 inside Docker as port 54320 on the host machine using the ports key
• uses a named volume, 'my_dbdata', for storing the database data using the volumes key. Even if the container and image are deleted, the volume will remain unless explicitly deleted using docker volume rm.
• for more information, see the Docker Compose file reference

Pull the postgres image from hub.docker.com, create a container named 'my_postgres', and start it in the background:

See that it's working¶

See the logs:

Try running psql:

Mac Postgres Password Change

hit CTRL+D to exit

For other commands such as starting, stopping, listing or deleting, see my Docker cheat sheet.

Stop Postgres Mac

Create a database¶

Connect using Python and psycopg2¶

Create a new file named myscript.py

Run it

Mac Postgres Password Manager

Errors¶

• If you get the above error, you can remove the container by running:

• If you get the above error, you can stop the container by running:

Postgres Mac Os X Password

See also¶