Hands-On Docker for Microservices with Python

Storing the version in the image

We want to have the version available inside the image. Because the image is immutable, doing so during the build process is the objective. The limitation we need to overcome here is that the Dockerfile process does not allow us to execute commands on the host, only inside the container. We need to inject those values in the Docker image while building.

A possible alternative is to install Git inside the container, copy the whole Git tree, and obtain the values. This is usually discouraged because installing Git and the full source tree adds a lot of space to the container, something that is worse. During the build process, we already have Git available, so we just need to be sure to inject it externally, ...