[rush] Add option to run bulk command in only specified project

[mikeharder]

• Feature

Currently, Rush has two options for running bulk commands:

  -t PROJECT1, --to PROJECT1
                        Run command in the specified project and all of its
                        dependencies
  -f PROJECT2, --from PROJECT2
                        Run command in all projects that directly or
                        indirectly depend on the specified project

These cover most of our needs, but sometimes we want to run a command in only a single project, and neither its dependencies nor projects which depend on it. It would be great if Rush could add an option for this, like:

  --only PROJECT1
                        Run command in only the specified project

It might be better to use a different name for the parameter to avoid confusion with the existing option:

  -o, --changed-projects-only
                        If specified, the incremental build will only rebuild
                        projects that have changed, but not any projects that
                        directly or indirectly depend on the changed package.

[apostolisms]

@mikeharder Do you envision this to be an option primarily for rush build or all commands? Can you give an example use case ?
Thanks

[mikeharder]

All commands. For example:

• You have 3 projects in a dependency chain A -> B -> C
• You have 3 command build, test and lint
• You want to validate a pull request which changes B

You would run these commands:

• rush build --to B --from B
  • Before you can build B, you need to build all its dependencies
  • You also want to build everything which depends on B, to ensure there are no breaking changes in B.
• rush test --from B
  • You should test B and everything which depends on it, again to ensure there are no breaking changes in B.
  • However, you do not need to run tests for the dependencies of B, since they are not changed in the pull request.
• rush lint --only B
  • You only need to run a static analysis tool like lint on code which has actually changed, not dependencies in either direction.

[octogonz]

Suppose there was also a project D, and someone did this:

rush build --to B --only D

I think I would expect it to build A+B+D. I wouldn't expect it to build "only" D.

Here are some other possible names to compare with:
rush build --to B --include D
rush build --to B --select D
rush build --to B --with D
rush build --to B --project D

BTW #1241 has a related discussion about project selection.

[mikeharder]

@octogonz: I agree the name --only is confusing if this option is composed with --to or --from. My favorite of the alternative names you proposed is --project, since it seems the clearest when used by itself:

rush build --include D
rush build --select D
rush build --with D
rush build --project D

[octogonz]

Currently the short name -p is used by --parallelism.

If we call it --project, I would definitely to use -p for that instead.

[mikeharder]

My favorite is still --project. If you want to avoid conflict with -p, you could use -j, --project.

[octogonz]

I agree --project is the best name. (That's why I removed the needs design tag heheh.)

[scamden]

i'd add a little suggestion to make --project take more than one. my use case would be a command to start up a certain constellation of dev servers. i.e rush servers --project backend-api frontend-ui or similar

[scamden]

aaaand just saw that --only already exists and can be used multiple times. please ignore.

can this issue be closed then? or were you using it to track renaming the option to --project?

[mikeharder]

Closing since I believe this issue has been fixed by #2422.

@octogonz: Feel free to re-open if you disagree.