Dockerfiles are written in a simple declarative text format , not a general-purpose programming language.

Quick Scoop

  • A Dockerfile is just a text file with Docker instructions like FROM, RUN, and COPY.
  • Docker itself is mainly implemented in Go , but that is separate from the language used in Dockerfiles.
  • If you’re thinking of docker-compose.yml, that file uses YAML syntax.

In plain terms

A Dockerfile is more like a recipe than code. You tell Docker what base image to start from, what commands to run, and how to build the final image.

For example, this is a Dockerfile-style instruction set, not a programming language program:

dockerfile

FROM python:3.12
WORKDIR /app
COPY . .
RUN pip install -r requirements.txt
CMD ["python", "app.py"]

Bottom line

So the short answer is: Dockerfiles are not written in a language like Python or Java; they use Docker’s own instruction syntax.