Generate less boilerplate code when making a new Go module

[penguinland]

This is a follow-up to #4455.

Nearly all modules can really have a 1-line main function, rather than all the boilerplate that gets generated in the current version.

Tried locally: running ./main module generate can make a new codebase whose main.go looks like this:

package main

import (
	"branch-module-one-space/models"
	"go.viam.com/rdk/module"
	"go.viam.com/rdk/resource"
	"go.viam.com/rdk/components/audioinput"
)

func main() {
	// ModularMain can take multiple APIModel arguments, if your module implements multiple models.
	module.ModularMain(resource.APIModel{ audioinput.API, models.BranchModelOnespace})
}

Running make not only successfully compiles everything, but main.go gets cleaned up like this (note the reordering of the imports, and the space removed from the APIModel constructor):

package main

import (
	"branch-module-one-space/models"
	"go.viam.com/rdk/components/audioinput"
	"go.viam.com/rdk/module"
	"go.viam.com/rdk/resource"
)

func main() {
	// ModularMain can take multiple APIModel arguments, if your module implements multiple models.
	module.ModularMain(resource.APIModel{audioinput.API, models.BranchModelOnespace})
}

[penguinland]

If I don't put a space between the { and the {{, it fails with Error: Unable to generate module: template: tmpl-main.go:12: unexpected "{" in command. I'd prefer to remove the space, but don't know how to get that to work.

[penguinland]

Similarly, \{{{ gives the same error, and {\{{ puts a literal backslash in the generated main.go, resulting in compiler errors later. Perhaps having the space is the least bad option. 😞

[jckras]

the space doesn't bother me too much! i agree i think its the best option.

[jckras]

lgtm! one question - you said "nearly all modules can have a 1-line main function", so how does this change affect the modules that need more than this?

[penguinland]

TBH, I said "nearly" because I was afraid of saying "all." 🙃 Show me a module where this doesn't work, and I'm confident its creator knows to do something different.

edit: ModularMain is the same as what this template used to be. If it doesn't work, the module creator would have needed to redo parts of main.go anyway.

[penguinland]

Rebased to fix conflicts with #4670...