Go project structure to produce library and cli with the same name in single repository

Question

How to setup project structure to produce library and cli with same name in single repository?

Suppose my project name is project. I want to make it importable with name project and have executable binary with name project when installed with go get. My setup currently is like this:

host.com/project/
    project/
        main.go
    core/
        project.go

Then, when installed with:

go get host.com/project/project

it installs project as executable which pulls core as dependency. In core/project.go file, the package has this:

package project

The problem is it is imported with:

import (
    "host.com/project/core"
)

And it exports project as name space not core which violates go's convention. How can I do this?

Answer 1

This isn't a convention, and you may do however you like, but it's a common practice to have a cmd folder in the project root, and all the executables go under that, each in is own folder.

So a good solution in your case could be simply:

host.com/project/
    cmd/
        project/
            project.go
    filea.go
    fileb.go

In filea.go and fileb.go the package declaration should be:

package project

In cmd/project/project.go package and import declaration should be:

package main

import "host.com/project"

Of course if your project is more complex, you may create further packages under the project root, and it may have multiple commands (multiple main packages), e.g.:

host.com/project/
    cmd/
        project/
            project.go
        prjtool/
            prjtool.go
    packagex/
        x.go
    packagey/
        y.go
    filea.go
    fileb.go

An example following this layout is the very popular Go Delve debugger (4.5k stars currently), available at https://github.com/derekparker/delve.

A very complex repository example is the golang.org/x/tools package which is a collection of multiple, essential Go tools, available at https://github.com/golang/tools/. Its cmd folder contains more than 20 subfolders (commands), many of the tools (main packages) even consist of multiple .go files (but each using package main declaration, forming a single package of the executable).

Also check out the following related question: What is a sensible way to layout a Go project