How to use App Platform's bindable environment variables in Dockerfile

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.

Submit an answer

This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

Sign In or Sign Up to Answer

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

Accepted Answer

👋 @echoTHIS

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.

Want to learn more? Join the DigitalOcean Community!

Join our DigitalOcean community of over a million developers for free! Get help and share knowledge in Q&A, subscribe to topics of interest, and get courses and tools that will help you grow as a developer and scale your project or business.