Docker and conda

I just read a blog post about Using Docker with Conda Environments. I do things slightly differently so I thought I would share an example of Dockerfile I use:

FROM continuumio/miniconda3:latest

# Install extra packages if required
RUN apt-get update && apt-get install -y \
    xxxxxx \
    && rm -rf /var/lib/apt/lists/*

# Add the user that will run the app (no need to run as root)
RUN groupadd -r myuser && useradd -r -g myuser myuser

WORKDIR /app

# Install myapp requirements
COPY environment.yml /app/environment.yml
RUN conda config --add channels conda-forge \
    && conda env create -n myapp -f environment.yml \
    && rm -rf /opt/conda/pkgs/*

# Install myapp
COPY . /app/
RUN chown -R myuser:myuser /app/*

# activate the myapp environment
ENV PATH /opt/conda/envs/myapp/bin:$PATH

I don't run source activate myapp but just use ENV to update the PATH variable. There is only one environment in the docker image. No need for the extra checks done by the activate script.

With this Dockerfile, any command will be run in the myapp environment.

Just a few additional notes:

1. Be sure to only copy the file environment.yml before to copy the full current directory. Otherwise any change in the directory would invalidate the docker cache. We only want to re-create the conda environment if environment.yml changes.

2. I always add the conda-forge channel. Check this post if you haven't heard of it yet.

3. I clean some cache (/var/lib/apt/lists/ and /opt/conda/pkgs/) to make the image a bit smaller.

I switched from virtualenv to conda a while ago and I really enjoy it. A big thanks to Continuum Analytics!