Ensure - If does not exist put option about docker-image-resource

[jondlm]

Would you guys accept a PR for this feature? It's something my company needs for our use-cases as well.

We're going to be doing a gradual transition to concourse and as such we'll have a mix of developers pushing images directly. Our registry, artifactory, doesn't allow the same tag to be pushed multiple times and causes docker push to throw a cryptic error message (manifest invalid: manifest invalid). This feature would prevent the builds from failing if a particular tag was already present on the registry; effectively making the put a no-op.

I'm thinking this should be a new parameter called prevent_overwrite and it will default to false. I'm open to better names for the parameter. I'm also planning to use docker inspect --type=image ${repository}:${tag_name} to check if the image already exists.

If my proposal is approved, is there a longer process that I'll need to follow to get my changes to flow through into concourse proper?

[concourse-bot]

Hi there!

We use Pivotal Tracker to provide visibility into what our team is working on. A story for this issue has been automatically created.

The current status is as follows:

• #135175651 Ensure - If does not exist put option

This comment, as well as the labels on the issue, will be automatically updated as the status in Tracker changes.

[ls-yann-david]

I only have one pipeline but I do like this feature. I was looking for something like this.

[jondlm]

I've since discovered that docker inspect --type=image only checks local tags, so it's not going to work for what I was hoping.