Hi all, I am curious if it is possible to interpolete env variables inside

BUILD

files? Seems it is not working for me, so I am just want to be sure 🙂 .

This is not possible, and that is by design.

BUILD

files need to have the same content on any machine, and if you could interpolate environment variables, that would make the content of the

BUILD

file depend on the environment. What are you trying to accomplish where you would need this?

Ok it makes sense. The problem I am trying to solve is publishing an image into AWS ECR. Unfortunately the URL of ECR repository looks like this:

<account_id>.dkr.ecr.<region>.<http://amazonaws.com|amazonaws.com>

In CI I would like to publish image to different accounts (representing PROD, DEV...). So I was thinking about using something like this in

BUILD

file:

docker_image(
    name="docker_image",
    repository="%(env.AWS_ACCOUNT)s.dkr.ecr.%(env.AWS_DEFAULT_REGION)<http://s.amazonaws.com/xxx|s.amazonaws.com/xxx>",
)

I know I can use

[docker.registries]

but I had some difficulties with it. Here are some examples I tried:

[docker.registries.ecr]
address = "%(env.AWS_ACCOUNT)s.dkr.ecr.%(env.AWS_DEFAULT_REGION)<http://s.amazonaws.com|s.amazonaws.com>"
repository = "{name}"
default = true

Seems that env variables are not supported inside address option.

[docker.registries.ecr]
repository = "%(env.AWS_ACCOUNT)s.dkr.ecr.%(env.AWS_DEFAULT_REGION)<http://s.amazonaws.com/{name}|s.amazonaws.com/{name}>"
default = true

address option is required.

[docker.registries.ecr-prod]
address = "<http://1111111111.dkr.ecr.eu-west-1.amazonaws.com|1111111111.dkr.ecr.eu-west-1.amazonaws.com>"
repository = "{name}"

[docker.registries.ecr-dev]
address = "<http://2222222222.dkr.ecr.eu-west-1.amazonaws.com|2222222222.dkr.ecr.eu-west-1.amazonaws.com>"
repository = "{name}"

This works but I do not know how to publish all changed images only into one repository (I mean when CI is running on

test

branch I want to publish all images to

ecr-dev

and when CI is using

main

branch then

ecr-prod

).

I think I had this problem long ago, but I was using a hand-rolled docker-plugin that took the registry as a command-line argument. It looks like the plugin here has another way of dealing with this but I don't know if that method of interpolation will work for repositories. If not, we may need to modify the plugin, and perhaps reach out to @curved-television-6568

Thanks. Think I found the easy solution. I will use default repository for local development:

[docker]
default_repository = "<http://111111111.dkr.ecr.west-1.amazonaws.com/{name}|111111111.dkr.ecr.west-1.amazonaws.com/{name}>"
tools = ["docker-credential-ecr-login", "getent"]
env_vars = ["AWS_ACCESS_KEY_ID", "AWS_SECRET_ACCESS_KEY", "AWS_SESSION_TOKEN"]

And in CI I will override it accourding to environment:

./pants --docker-default-repository="<http://2222222222.dkr.ecr.eu-west-1.amazonaws.com/{name}|2222222222.dkr.ecr.eu-west-1.amazonaws.com/{name}>" package ::

FWIW, I'm pretty sure the interpolation that failed there for you was dict value interpolation which was very recently fixed on main (2.14.x): https://github.com/pantsbuild/pants/pull/16481

@plain-truck-80265 glad you found the ability to set the default registry from command line, was going to be my suggestion. Also as John points out, the env interpolation for your configuration you tried with initially will work from Pants 2.14.0 as it was just recently fixed.

Thank you @enough-analyst-54434 and @curved-television-6568 I can confirm it works.