Clarify that rosetta and DEFAULT_PLATFORM should **not** be used in Mac + Docker

[marcosnils]

What is the issue?

Some Mac users have been having issues lately as they have either rosetta or the DEFAULT_PLATFORM variable set to something other than arm64 when using Dagger with Docker Desktop installed. ref: https://discord.com/channels/707636530424053791/1232715125480493127

We should add a note in our docs that in case of issues running our hello example in Mac + Docker Desktop, to double check this. It's also important to clarify that if they effectively ran into this issue, the way to fix it is by ensuring that neither rosetta and DEFAULT_PLATFORM is set, remove the current pulled engine image, and to try again.

ref: https://discord.com/channels/707636530424053791/1232715125480493127/1233172844427481240

[vikram-dagger]

@marcosnils a few questions:

• is this different from the troubleshooting guidance at https://docs.dagger.io/manuals/user/932727/troubleshooting#calling-a-dagger-function-fails-when-docker_default_platform-is-set

if yes:

• what is the error message the user sees in this case? is it always moduleSource.withContextDirectory.asModule resolve: failed to create module: select: failed to update codegen and runtime: failed to generate code: failed to get modified source directory for go module sdk codegen:? are there any others?
• the way to fix it is by ensuring that neither rosetta and DEFAULT_PLATFORM is set, remove the current pulled engine image, and to try again. -> can you provide a set of commands for this, that a user could copy-paste?
• does this error appear only with the hello example in the quickstart, or with any dagger call command? This would determine whether (a) we document it generically in the troubleshooting guide and link to it in the quickstart or (b) we document it specifically for the quickstart?

[marcosnils]

• is this different from the troubleshooting guidance at https://docs.dagger.io/manuals/user/932727/troubleshooting#calling-a-dagger-function-fails-when-docker_default_platform-is-set

it overlaps with that troubleshooting section, yes, but there are some differences. I think we could improve to make sure that users check for both the rosetta and the DEFAULT_PLATFORM issue.

• the way to fix it is by ensuring that neither rosetta and DEFAULT_PLATFORM is set, remove the current pulled engine image, and to try again. -> can you provide a set of commands for this, that a user could copy-paste?

1. Check that DEFAULT_PLATFORM is not set in your current shell and/or your equivalent shell config files (.bashrc, .profile, .zshrc, etc)
2. Validate that rosetta is disabled in Docker Desktop (https://docs.docker.com/desktop/settings/mac/)
3. Remove any running engine containers and docker images: docker rm -fv $(docker ps --filter name="dagger-engine-*" -q) && docker rmi $(docker images -q --filter reference=registry.dagger.io/engine)

• does this error appear only with the hello example in the quickstart, or with any dagger call command? This would determine whether (a) we document it generically in the troubleshooting guide and link to it in the quickstart or (b) we document it specifically for the quickstart?

It'll appear with any dagger call