Ensure - If does not exist put option

I have a scenario where build of the same docker image can be triggered from many different pipelines. I would like to reduce the time this task will take if the image already exists.

I know that this does not seem to make a lot of sense - if the existing one is not exactly the same as the one that is going to be produced. I am handling this outside, but build if needed option could be also considered for the plugin (it is not as hard if you design the dockerfile with such feature in mind).

Anyways, what I would like to see is if this option is enabled the put command to first check if a docker image at the repo with the tag is already there and simply exit with success.

Start by locating the resource's put command and the code that addresses a Docker image repository and tag. Check how existing image metadata and registry access are handled before deciding where the option belongs. Done means the enabled option exits successfully when the tagged image already exists, while normal behavior remains unchanged.