Confused how the golang project-layout repo works in practice - go

Question

This question is in reference to the popular project-layout.
Is this simply a way to lay out the code, but the actual compilation of a binary will be in the
/cmd/app1/
/cmd/app2/
So if I have a website, it would still be considered a cmd application that would simply start the http listener etc.
Or are there several "entry" points throughout the layout and not just in the cmd folders?
How exactly would you actual build and run your application using this layout? (or one of them since from what I understand it supports multiple)
is it like:
go build cmd/app1/*.go ?

Answer 1

You can just
go build ./cmd/app/
For example I have this module
├── cmd
│   ├── cli
│   │   └── main.go
│   └── web
│   └── main.go
├── go.mod
└── service
└── service.go
go.mod is just
module example
service.go:
package service
import "fmt"
func DoSomething() {
fmt.Println("service processing")
}
cmd/web/main.go:
package main
import (
"example/service"
"fmt"
)
func main() {
fmt.Println("starting web program")
service.DoSomething()
}
cmd/cli/main.go:
package main
import (
"example/service"
"fmt"
)
func main() {
fmt.Println("starting cli program")
service.DoSomething()
}
Build (From root)
Build web:
go build ./cmd/web/
This will create binary file web
run web
./web
// output:
// starting web program
// service processing
Build cli:
go build ./cmd/cli/
run web
./web
// output:
// starting cli program
// service processing

Answer 2

If you want to build all of your apps inside a folder you can do like this :
go install ./...
this will build all your apps in bin folder inside GOPATH then you can run whatever app you like.
But if you want to build and run a specific app you can go to that folder and simply run.
go build
As long as there is a main package in that folder you can build your program.