# r-builds

The environment which produces R builds obtainable from: https://cdn.rstudio.com/r/versions.json

## Adding a new platform.

### Dockerfile

Create a `builder/Dockerfile.platform-version` (where `platform-version` is `ubuntu-1604` or `centos-74`, etc.) This file must contain four major tasks:

1. an `OS_IDENTIFIER` env with the `platform-version`.
2. a step which ensures the R source build dependencies are installed
3. The `awscli`, most likely installed via `pip` for uploading tarballs to S3
4. `COPY` and `ENTRYPOINT` for the `build.sh` file in `builder/`.

### docker-compose.yml

A new service in the docker-compose file named according to the `platform-version` and containing the proper entries:

```
command: ./build.sh
environment:
  - R_VERSION=${R_VERSION} # for testing out R builds locally
  - LOCAL_STORE=/tmp/output # ensures that output tarballs are persisted locally
build:
  context: .
  dockerfile: Dockerfile.debian-9
image: r-builds:debian-9
volumes:
  - ./integration/tmp:/tmp/output  # path to output tarballs
```

### Job definition

IN `serverless-resources.yml` you'll need to add a job definition that points to the ECR image.

```
rBuildsBatchJobDefinitionDebian9:
  Type: AWS::Batch::JobDefinition
  Properties:
    Type: container
    ContainerProperties:
      Command:
        - ./build.sh
      Vcpus: 4
      Memory: 4096
      JobRoleArn:
        "Fn::GetAtt": [ rBuildsEcsTaskIamRole, Arn ]
      Image: #{AWS::AccountId}.dkr.ecr.#{AWS::Region}.amazonaws.com/r-builds:debian-9
```

### Environment variables in the serverless.yml functions.

The serverless functions which trigger R builds need to be informed of new platforms.

1. Add a `JOB_DEFINITION_ARN_PlatformVersion` env variable with a ref to the Job definition above.
2. Append the `platform-version` to `SUPPORTED_PLATFORMS`.

```
environment:
  # snip
  JOB_DEFINITION_ARN_debian_9:
    Ref: rBuildsBatchJobDefinitionDebian9
  SUPPORTED_PLATFORMS: ubuntu-1604,ubuntu-1804,debian-9
```

### Makefile

In order for the makefile to push these new platforms to ECR, add them to the PLATFORMS variable near the top of the Makefile

### Submit a Pull Request

Once you've followed the steps above, submit a pull request. On successful merge, builds for this platform will begin to be available from the CDN.

## "Break Glass"

Periodically, someone with access to these resources may need to re-trigger every R version/platform combination. This quite easy with the `serverless` tool installed.

```
serverless invoke stepf -n rBuilds -d '{"force": true}'
```