Allow setting a new image for a service

[xavier-romero]

Background & motivation

For testing upgrading versions of production environment I'd like to use Kurtosis to fully reproduce/document the procedure.
For this, I'd love to have the option to JUST change the docker image for a running service.

Desired behaviour

I'd love to be able to do something like this:
kurtosis service update enclave_name service_name --image whatever_docker_image:tag
So that just:

• Stops and removes the docker
• Recreates the service with the new image maintaining all existing config/properties/files/ports/etc.

Whatever impact it could have on the whole stack is under user responsability.

How important is this to you?

Painful; the lack of this feature makes using Kurtosis frictionful.

What area of the product does this pertain to?

CLI: the Command Line Interface

[samlaf]

Belive kurtosis service add enclave_name SAME_SERVICE_NAME new_image_name will do what you are looking for. I've been using it to change the flags passed to a service. Having something like kubectl edit would be nice though, for cases where the service is already started with a huge number of commands, flags, files, ports, etc. Having to rewrite them all by hand (correctly!) if they were created programatically by some starlark code can be painful.

[tedim52]

@samlaf just made me realize this as well actually - that logic is here:

kurtosis/core/server/api_container/server/startosis_engine/kurtosis_instruction/add_service/add_service.go

Line 206 in bf315c6

if exist {

Although with the service add you would have to provide all the other again - so an update that upserts the config would be useful.

[xavier-romero]

Indeed there are services with many ports, artifacts, env, etc, that are set by starlark code. Asking the user to recreate everything is rude and painful.
If at least we had a simple way to achieve it. Something like that could do the trick as well:
kurtosis service dump enclave_name service_name --json | jq '.image = "new_image"' | kurtosis service add enclave_name service_name --json-input