Dockerfile Dynamic Environment Variable, Setting them when using

Dockerfile Dynamic Environment Variable, Setting them when using run command works but I need to set them during the build. To use values inside the dockerfile you need to pass build args Isnt there an easier way to do this? Jan 15, 2026 · Certain environment variables affect the build process: In the Docker build, NODE_OPTIONS="--max-old-space-size=24000" is set to handle large compilation workloads. github/workflows/ci. Sources: Dockerfile. Turns out env_file only sets values inside the container, environment sets values only inside the compose file and bash script. , database URLs, API keys, feature flags) into containers without hard-coding them into your code or Dockerfile. I'm trying to set environment variables in docker container during the build but without success. In the context of Docker, these variables can be set in the Dockerfile using the ENV instruction. 3 days ago · The development environment is defined by a single-stage Dockerfile that extends the official ros:foxy base image. The ENV defines an environment variable which is passed to the container. What you need to do is to provide a value for your value variable to the container you are creating. Nov 26, 2025 · Conclusion Dockerfile-scoped variables provide a secure, efficient way to manage build-time configuration without persisting unnecessary data in images. This is the complete guide to build-time arguments, environment variables and docker-compose templating. Ever wanted to have dynamically-set environment variables when writing a new Dockerfile for building your image? Not dynamically-set before you start building the image (that’s a job for ARG and –build-arg), but set during the image build process, while the Dockerfile lines are interpreted, not bound to the host machine in any way. I wondering if there is a way to allow our Dockerfile (docker image that is uploaded to ECR) to use a dynamic variable instead of a static variable (like shown above). Using build-time environment variables for Dockerfile builds If you are building your application via Dockerfile and require environment variables to be used during the build process, you can use the ARG keyword to make these variables available to your Dockerfile and the ${env-var-name} syntax to reference them elsewhere in the file. 5 days ago · Configuration Architecture Overview DataAgent's configuration system follows a hierarchical structure with Spring Boot's externalized configuration mechanism, allowing properties to be overridden via environment variables, command-line arguments, or external configuration files. The result was that I Feb 24, 2022 · You can't set Dockerfile environment variables to the result of commands in a RUN statement. yml 14 Production Optimizations Production builds enable optimizations not present in development: Minification and tree shaking Stop struggling to build Docker images and configuring your dockerized apps. They let you inject dynamic values (e. The Problem with Vite and Environment Variables 2. You do this by specifying by issuing a run command like the following: Oct 22, 2017 · How to set dynamic value in environment variable in dockerfile using shell script Asked 7 years, 7 months ago Modified 7 years, 7 months ago Viewed 5k times Oct 31, 2022 · Background My project started with cookiecutter-django a few years ago, and the compose portion of the project has had numerous changes over time as I learned more about the technology and as the project goals became more clear. base 10 . Using build arguments and environment variables to configure builds Jun 18, 2024 · Introduction 1. Variables set in a RUN statement are ephemeral; they exist only while the RUN statement is active If you don't have access to the host environment (to pass arguments to the docker build command), you're not going to be able to do exactly what you want. ts` file structure, and how configuration is loaded and applied at build-time and Mar 19, 2024 · We can use environment variables when performing a docker build. By using ARG for build-time variables, inline shell variables for short-lived commands, and --build-arg for dynamic builds, you can keep your Dockerfiles clean, secure, and flexible. Mar 19, 2019 · The ARG defines a variable to be used inside the dockerfile in subsequent commands. First, we’ll demonstrate us Oct 16, 2024 · Learn about the ARG and ENV instructions and explore how to use them in your Dockerfiles to make your images more configurable and easier to maintain. The postCreateCommand actions are run once the container is created, so you can also use the property to run commands like npm install or to execute a shell script in your source tree (if you have mounted it). Dec 11, 2025 · How to Load Multiple Environment Variables Without Cluttering Your Dockerfile: A Step-by-Step Guide Environment variables are the lifeblood of configuring applications in Docker. Dockerfile - Defining an ENV variable with a dynamic value Asked 10 years ago Modified 11 months ago Viewed 12k times Environment variables are a convenient way to externalize application configuration; therefore, they’re also useful for building Docker containers. In this short tutorial, we’ll learn how to pass an environmental variable value intoDockerfile. . It is possible to set the variables in the Dockerfile before running the container and use them in your Environment variables are dynamic values that can affect the way running processes will behave on a computer. If you have ephemoral hosts and using something like ECS, Registrator… Turns out env_file only sets values inside the container, environment sets values only inside the compose file and bash script. However, passing and using them in the Dockerfileisn’t as easy as it could be. These can be hard-coded into our Dockerfile, or passed as parameters into the build process. A Dockerfile is most suitable for installing packages and tools independent of your workspace files. To use values inside the dockerfile you need to pass build args Isnt there an easier way to do this? I wondering if there is a way to allow our Dockerfile (docker image that is uploaded to ECR) to use a dynamic variable instead of a static variable (like shown above). 5 days ago · This page documents the Switchboard backend service configuration system, including environment variables, the `config. We look at how to use these techniques to build variations of image from the same Dockerfile. The container includes a complete toolchain for PDU generation across all target languages. Jun 18, 2024 · Introduction 1. g. Oct 21, 2023 · In the previous approach, the script processed each environment variable individually, running a sed operation for each file and environment variable. For example, if you had 10 environment variables and 1,000 files, this would result in 10,000 sed operations—one for each combination. The Concept: Build Once, Inject Tagged with vite, docker, webdev, devops. You might have a use case to dynamically add environment variables to docker containers. Jul 29, 2020 · At this stage the environment variable var_name is not populated, so during the building phase docker will create an image with the value environment variable set to empty. Looking for a way to pass environment variables during your Docker image build? Here are multiple ways you can get environment variables into your images, and to your future Docker containers. Dockerfile FROM Feb 24, 2022 · You can't set Dockerfile environment variables to the result of commands in a RUN statement. Dec 26, 2023 · Environment variables are the variables which can be used in both build and run time. uhfl, xwpu, aolqsi, qmka, ndoc, 9kgh, cww9di, mv0877, c3bn, kf8mr,