CODEWITHSUNDEEP
dockerdockerfiledocker-secrets
JackTheKnife
JackTheKnife

Reputation: 4144

Dockerfile RUN command with passed argument

I'm trying to pass an argument to the docker build to have it executed in the Dockerfile as

RUN --mount=type=secret,id=$SECRET_NAME cp /run/secrets/$SECRET_NAME /etc/app/conf

but that will fail during the build time as

 > [8/8] RUN --mount=type=secret,id=mysecret cp /run/secrets/mysecret /etc/app/conf:
#13 0.224 cp: cannot stat '/run/secrets/mysecret': No such file or directory

but when I will use it directly in the RUN command as

RUN --mount=type=secret,id=mysecret cp /run/secrets/mysecret /etc/app/conf

that will work.

Any thoughts?

Upvotes: 0

Views: 324

Answers (1)

ErikMD
ErikMD

Reputation: 14723

It seems the feature you suggest ("environment variable expansion of the secret identifier itself") is just not supported by BuildKit, cf. the following two references:

So maybe you could just refactor your Dockerfile so it does not require this feature (which by the way, would have the drawback to hinder legibility/reproducibility, given one could not know the secret identifier just by looking at the sole RUN --mount=… command).

Upvotes: 1

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