CODEWITHSUNDEEP
dockerdockerfileaws-codebuildamazon-ecr
Parthiva
Parthiva

Reputation: 290

Parameterising Docker Image prefix

I have a Dockerfile which has the following content

# Build
FROM ${ECR_PREFIX}/maven:3.6.3-jdk-11 AS build
COPY src /home/app/src
COPY pom.xml /home/app
RUN mvn -f /home/app/pom.xml clean package

# Package
FROM ${ECR_PREFIX}/openjdk:11-jre-slim
COPY --from=build /home/app/target/application.jar application.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "application.jar"]

I tried to build this using

export PREFIX=${AWS::AccountId}.dkr.ecr.${AWS::Region}.amazonaws.com
docker build -t backend --build-arg ECR_PREFIX=$PREFIX .

but this would not work. I am really trying not to hard code the prefix especially ${AWS::AccountId} part of it because of various reasons.

Any pointers here?

Upvotes: 1

Views: 1635

Answers (1)

David Maze
David Maze

Reputation: 158848

You have to explicitly declare the ARG in your Dockerfile. If you use an ARG value in a FROM line then the ARG needs to come before any FROM. (Other ARGs need to be repeated in each build stage that uses them.)

ARG REGISTRY=docker.io
FROM ${REGISTRY}/maven:3.6.3-jdk-11 AS build

REGISTRY=${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com
docker build \
  -t $REGISTRY/backend:$(git rev-parse HEAD) \
  --build-arg REGISTRY=$REGISTRY \
  .

Upvotes: 3

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