What does x-airflow-common do in the airflow docker-compose.yaml file

user_6352735 0
Viewed 351

Decided to try and really understand the docker-compose.yaml file for airflow. At the beginning of the file there is this piece of code.

x-airflow-common:
  &airflow-common
  image: ${AIRFLOW_IMAGE_NAME:-apache/airflow:2.2.5}

What I'm gathering is that x-airflow-common is defining a variable and that the the &airflow-common says that "any image in this file that points to *airflow-common look here. That is why further down we see.

<<: *airflow-common

Which says "look in this docker-compose file for the image declared in airflow-common" then when it runs the command against the image: scheduler, celery worker etc. The airflow image sees those commands and knows what type of image to spin up for that container.

Hoping someone can confirm/correct my assumptions or point me to good documentation for this. I've been searching the past two days, but have been unable to locate anything that "dissects" this file.

airflow docker-compose
1 Answers

This uses a feature in Docker Compose called YAML anchors. It allows you to create a sort of template block, and then create other services that are based on that template, but replace certain settings in it.

This section on the Compose specification docs can probably explain it better than I can.

user_190037570
Related