Environment variables at build time with Docker
Introduction Do you need a certain environment variable at build time in Docker as opposed to runtime? There is an easy way to achieve this. Use Docker build arguments in combination with environment variables. An example of this is below of a React JS docker build that needs the environment variable REACT_APP_BACKEND_API and build time in the command npm run build. # Declare the build argument in the global scope ARG REACT_APP_BACKEND_API_ARG=TEST # Use an official Node runtime as a parent image FROM node:20-alpine # Set the working directory WORKDIR /app # Copy package....