That way you don't accidentally start a prod container in dev or a dev container in prod. You may want to omit CMD entirely and always pass in 0 dev or 1 prod as arguments to the run command. Running it in dev would use the same command docker run -p 9000:9000 -d me/appĪnd running it in prod you would pass the parameters to the run command docker run -p 9000:9000 -d me/app 1 prod Using this approach, your Dockerfile will look something like FROM. The docs have an example in Exec form ENTRYPOINT example. When using the exec form and executing a shell directly, as in the case for the shell form, it is the shell that is doing the environment variable expansion, not docker.Īnother option is to use ENTRYPOINT to specify that node is the executable to run and CMD to provide the arguments. If you want shell processing then either use the shell form or execute a shell directly, for example: RUN. This means that normal shell processing does not happen.įor example, RUN will not do variable substitution on $HOME. Unlike the shell form, the exec form does not invoke a command shell.

Same idea with Builder RUN (applies to CMD as well): When you use the JSON syntax, you're explicitly requesting that your command bypass the shell and be executed directly. The explanation is that the shell is responsible for expanding environment variables, not Docker. Your Dockerfile CMD can use that environment variable, but, as mentioned in issue 5509, you need to do so in a sh -c form: CMD Or you can set them through your compose file: node: 4 With electron-builder NSIS installer we're able to create an executable installer which launches the installed electron app immediately after the install is finished. Then you can pass an environment variable with docker run docker run -p 9000:9000 -e environment=dev -e cluster=0 -d me/app The npx binary was rewritten in npm v7.0.0, and the standalone npx package deprecated at that time.npx uses the npm exec command instead of a separate argument parser and install process, with some affordances to maintain backwards compatibility with the arguments it accepted in previous versions. Make sure your Dockerfile declares an environment variable with ENV: ENV environment default_env_value

Install builder exec args