Question
How to use App Platform's bindable environment variables in Dockerfile
- Posted November 4, 2020
- DockerDigitalOcean App Platform
I was following the tutorial on How to Use Environment Variables in App Platform, and I am unable to figure out how to use these convenience variables in my Dockerfile.
I am specifically trying to print the COMMIT_HASH to a file in the container of my web component.
ARG web.COMMIT_HASH=unspecified
RUN echo ${web.COMMIT_HASH} > /www/commithash.txt
I’ve also tried pulling it in using ENV but that fails during build.
ENV GITHASH=${web\.COMMIT_HASH:-unspecified}
RUN echo ${GITHASH} > /www/githash.txt
It errors out at the . dot.
So is there a way to get these convenience environment variables into my Dockerfile?
Any help is greatly appreciated.
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Great question, bindable variables are a template system for environment variables, not environment variables themselves.
You could create a environment variable called GITHASH with a value of ${web.COMMIT_HASH} in the DO App Platform UI. When we build or deploy your app we will inject an environment variable of $GITHASH with your commit hash.
