diff --git a/develop/develop-images/build_enhancements.md b/develop/develop-images/build_enhancements.md index 1082e27348..1393bb119b 100644 --- a/develop/develop-images/build_enhancements.md +++ b/develop/develop-images/build_enhancements.md @@ -113,10 +113,10 @@ $ docker build --progress=plain . The new syntax features in `Dockerfile` are available if you override the default frontend. To override the default frontend, set the first line of the -`Dockerfile` as a comment with a specific frontend image: +`Dockerfile` as a comment with a specific frontend image: ```dockerfile -# syntax=, e.g. # syntax=docker/dockerfile:1 +# syntax=, e.g. # syntax=docker/dockerfile:1.2 ``` The examples on this page use features that are available in `docker/dockerfile` @@ -146,11 +146,12 @@ For example, with a secret piece of information stored in a text file: $ echo 'WARMACHINEROX' > mysecret.txt ``` -Within a Dockerfile that uses BuildKit frontend `docker/dockerfile:1.2` or up, -the secret can be accessed using the `--mount` option: +And with a Dockerfile that specifies use of a BuildKit frontend +`docker/dockerfile:1.2`, the secret can be accessed when performing a `RUN`: ```dockerfile -# syntax=docker/dockerfile:1 +# syntax=docker/dockerfile:1.2 + FROM alpine # shows secret from default secret location: @@ -160,6 +161,7 @@ RUN --mount=type=secret,id=mysecret cat /run/secrets/mysecret RUN --mount=type=secret,id=mysecret,dst=/foobar cat /foobar ``` +The secret needs to be passed to the build using the `--secret` flag. This Dockerfile is only to demonstrate that the secret can be accessed. As you can see the secret printed in the build output. The final image built will not have the secret file: