Add support for starterProjects in v2 devfiles

[johnmcollier]

/kind user-story

User Story

As a user, I want to be able to select a starter project when running odo create and have odo pull down that project's source code for use. I should also be able to select the starter code with the --starter flag (replacing the current --downloadSource flag)

Acceptance Criteria

• The devfile parser should be updated to support the starterProjects field
• It should allow the user to select a project when running odo create.
• The user should be able to pick from multiple starter projects, if they are present

Links

devfile/api#42

Originally discussed in #3216. As starterProjects is not yet part of the devfile v2 schema (though it has been agreed to, see devfile/api#42), it was left out of the initial devfile-v2 implementation in odo.

/kind user-story
/area devfileV2

[kadel]

We will also want to think how we handle sync as part of this story. Currently, if there is a single project defined in the devfile, we sync to /projects/<projectName>, otherwise we sync to /projects.
We need to think about how the starterProjects field will affect that, and where the code should get synced to when there are starter projects defined in a devfile.

My understanding is that the starterProject is just a template of a project.
If I run odo create devfile --downloadSource the starter project from the devfile should get downloaded to the current directory. This is the only place and operation where the starterProject would be used.
btw: we should probably rename --downloadSource to something more fitting like --starter

Then the file syncing process only depends on projects definition in a devfile and it should use the logic that you described.
But the starterProject shouldn't have any effect on the file syncing, it is just used to populate the local directory so users can easily start a new project.

[kadel]

starterProject field is getting added to devfile v2 spec and schema here devfile/api#92

[adisky]

Things need to be done to support starter projects.

• schema update (After this one gets merged) add starterProject fields devfile/api#92
• if --starter flag is specified download the first project
• user can specify starter project name --starter <starter-project-name>, downloads that project
• should list the starterProjects in interactive mode and user should be able to pick one of them
• starter projects have different behavior than projects in terms of cloning the repo
  starterProjects and projects description devfile/api#42 (comment)
• syncing mechanism needs to be updated for starter projects, sync them to CHE_PROJECTS_ROOT or /projects

[adisky]

@kadel @johnmcollier Most things we are already doing for projects, git cloning mechanism and file sync path needs to be changed.

I have a question what we need to do about projects then? how we could download them?