Include Dart beta in Cloud Build stage/deploy image

[parlough]

Adding Dart to the image as we want to use Dart in the site build. Using beta as sometimes we depend on upcoming features, particularly when preparing for a new stable release.

[parlough]

@athomas I'm not really familiar with Cloud Build, do you see any problems with making this change or is there a better way to do this (using a mirrored version of the official Dart Docker image?). Thanks for any insight you have :)

[athomas]

Any reason to not just change the first line to the Dart official image?
FROM dart:beta

[parlough]

I wasn't sure if it Cloud Build required using a gcr.io hosted image as the base image, so I went with this.

Looking more now though, https://cloud.google.com/build/docs/interacting-with-dockerhub-images does explicitly mention docker hub images are supported, so I'll try it out! Has the added benefit of supporting arm if needed.

[athomas]

@athomas I'm not really familiar with Cloud Build, do you see any problems with making this change or is there a better way to do this (using a mirrored version of the official Dart Docker image?). Thanks for any insight you have :)

I wouldn't exactly call myself a Cloud Build expert, but thanks for your trust :)

I'd say it would be nice to use the Dart official image (also to dogfood our own products). But what you have should work as well.