sbt-ecr

An SBT plugin for managing Docker images within Amazon ECR.

Features

• Create ECR repositories using ecr:createRepository
• Login to the remote registry using ecr:login
• Push local images using ecr:push

Installation

Add the following to your project/plugins.sbt file:

addSbtPlugin("com.mintbeans" % "sbt-ecr" % "0.16.0")

Add ECR settings to your build.sbt. The following snippet assumes a Docker image build using sbt-native-packager:

import com.amazonaws.regions.{Region, Regions}

enablePlugins(EcrPlugin)

region           in Ecr := Region.getRegion(Regions.US_EAST_1)
repositoryName   in Ecr := (packageName in Docker).value
localDockerImage in Ecr := (packageName in Docker).value + ":" + (version in Docker).value

// Create the repository before authentication takes place (optional)
login in Ecr := ((login in Ecr) dependsOn (createRepository in Ecr)).value

// Authenticate and publish a local Docker image before pushing to ECR
push in Ecr := ((push in Ecr) dependsOn (publishLocal in Docker, login in Ecr)).value

Keep in mind that ecr:createRepository is a completely optional step. If you have a managed infrastructure (e.g. create everything, including the repository, using AWS CloudFormation, Terraform or some other tool), then it might be better to skip this step, and assume that the repository exist, when you trigger the process.

That being said, it's a convenient feature, when you don't rely on any tool like this. We support several policy-related settings, that will allow you to fine-tune the repository, if needed (read ahead).

Usage

The plugin follows common security conventions. That is, you can use the following authentication methods:

• provide AWS_ACCESS_KEY_ID and AWS_SECRET_KEY as environment variables.
• provide aws.accessKeyId and aws.secretKey as system properties.
• use a profile specified by the AWS_DEFAULT_PROFILE environment variable.
• use the EC2 instance profile when the process is run directly in Amazon EC2.

To make it work locally, you may configure an AWS profile according to the reference page, and spawn the push process as such:

AWS_DEFAULT_PROFILE=<your_profile_name> sbt ecr:push

Tagging

By default, the produced image will be tagged as "latest". It is possible to provide arbitrary additional tags, for example to add the version tag to the image:

repositoryTags in Ecr ++= Seq(version.value)

If you don't want latest tag on your image you could override the repositoryTags value completely:

repositoryTags in Ecr := Seq(version.value)

If you want to make the tag environment-dependent you can use the following template:

repositoryTags in Ecr := sys.env.get("VERSION_TAG").map(Seq(_)).getOrElse(Seq("latest"))

And trigger the process using:

VERSION_TAG=myfeature sbt ecr:push

Tag immutability

By default, when the createRepository task is executed, the new repository will have Tag immutability disabled. You can control this behavior using the following setting:

imageTagsMutable in Ecr := false

Cross account publishing

By default, when the login task is executed, authentication will target the registry id and repository domain of the AWS account belonging to the role used.

If you need cross account authentication, you can override registry domain and target any registry id.

Example usage:

repositoryDomain in Ecr := Some("myecr.example.com")
registryIds in Ecr ++= Seq("your AWS account id")

Repository security policy configuration

By default, when the createRepository task is executed, the new repository does not have a security policy attached.

When you set repositoryPolicyText in your build.sbt file, and the createRepository is called, the created repository will have the configured policy.

Example usage:

repositoryPolicyText in Ecr := Some(IO.read(file("project") / "ecrpolicy.json")) 

Then in the project/ecrpolicy.json you can set your policy text. For example:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "BuildServerAccess",
      "Effect": "Allow",
      "Principal": {
        "AWS": [
          "arn:aws:iam::YOUR_ACCOUNT_ID_HERE:role/YOUR_IAM_ROLE_NAME_HERE"
        ]
      },
      "Action": [
        "ecr:*"
      ]
    }
  ]
}

Configuring repositoryPolicyText will not affect existing repositories.

Repository lifecycle policy configuration

Configuring the repository lifecycle policy works the same as configuring the policy in the previous chapter.

By default, when the createRepository task is executed, the new repository does not have a lifecycle policy attached.

When you set repositoryLifecyclePolicyText in your build.sbt file, and the createRepository is called, the created repository will have the configured lifecycle policy.

Example usage:

repositoryLifecyclePolicyText in Ecr := Some(IO.read(file("project") / "ecrlifecyclepolicy.json")) 

Then in the project/ecrlifecyclepolicy.json you can set your policy text. For example:

{
  "rules": [
    {
      "rulePriority": 10,
      "description": "Lifecycle of release branch images",
      "selection": {
        "tagStatus": "tagged",
        "tagPrefixList": [
          "release"
        ],
        "countType": "imageCountMoreThan",
        "countNumber": 20
      },
      "action": {
        "type": "expire"
      }
    }
  ]
}

Configuring repositoryLifecyclePolicyText will not affect existing repositories.