Docker Build Arguments
This project demonstrates how environment variables are made available to scripts within Docker builds via build arguments.
| Command | Result |
|---|---|
docker build . |
MY_ENV_VAR is undefined. |
MY_ENV_VAR=foo docker build . |
MY_ENV_VAR is undefined (within the execution context of start.js) because it was never made available to each build step as a build argument. |
docker build . --build-arg MY_ENV_VAR=foo |
MY_ENV_VAR equals "foo" because it was explicitly set to "foo". |
MY_ENV_VAR=foo d build . --build-arg MY_ENV_VAR |
MY_ENV_VAR equals "foo" because build arguments assume the environment value by default. |