Why does my GitHub Actions script cannot find my internal go package?

Question

I'm learning Go and want to make use of GitHub Actions. Everything is fine when working with just one package. But as soon as I define more than one package (more than the main package), I get stucked. On my desktop it does compile, but by using Actions script it does not and ends up in following error:

Run go build -v main.go
main.go:4:2: cannot find package "Landsat-Extractor/logger" in any of:
    /opt/hostedtoolcache/go/1.14.4/x64/src/Landsat-Extractor/logger (from $GOROOT)
    /home/runner/go/src/Landsat-Extractor/logger (from $GOPATH)
##[error]Process completed with exit code 1.

The file structure is:

go
└───src
    └───Landsat-Extractor
        │   main.go
        │
        └───logger
        |   │   logger.go
        |
        └───.github
            └───workflows
                |   go.yml

On my local machine GOPATH is set to go of the previous file structure.

My Actions script go.yml is:

name: Go

on:
  push:
    branches: [ master, feature_githubaction ]

jobs:

  build:
    name: Build
    runs-on: ubuntu-latest
    steps:

    - name: Set up Go 1.x
      uses: actions/setup-go@v2
      with:
        go-version: ^1.14
      id: go

    - name: Check out code into the Go module directory
      uses: actions/checkout@v2

    - name: Build
      run: go build -v main.go

The main.go is:

package main

import (
    "Landsat-Extractor/logger"
)

func main() {

    logger.Create()
    defer logger.Destroy()

    logger.Info("A message")

}

The logger.go is:

package logger

// Create inits the Logger
func Create() {
    println("Creating")
}

// Info logs a message
func Info(msg string) {
    println(msg)
}

// Destroy closes writers
func Destroy() {
    println("Closing")
}

Answer 1

In ~/go/src/Landsat-Extractor run go mod init

This would help to resolve your module imports.