How to run command during Docker build which requires a tty?

Question

I have some script I need to run during a Docker build which requires a tty (which Docker does not provide during a build). Under the hood the script uses the read

Answer 1

Most likely you don't need a tty. As the comment on the question shows, even the example provided is a situation where the read command was not properly called. A tty would turn the build into an interactive terminal process, which doesn't translate well to automated builds that may be run from tools without terminals.

If you need a tty, then there's the C library call to openpty that you would use when forking a process that includes a pseudo tty. You may be able to solve your problem with a tool like expect, but it's been so long that I don't remember if it creates a ptty or not. Alternatively, if your application can't be built automatically, you can manually perform the steps in a running container, and then docker commit the resulting container to make an image.

I'd recommend against any of those and to work out the procedure to build your application and install it in a non-interactive fashion. Depending on the application, it may be easier to modify the installer itself.