Skip to content

Latest commit

 

History

History
181 lines (134 loc) · 4.37 KB

lab1.md

File metadata and controls

181 lines (134 loc) · 4.37 KB

Lab 1: Experiments with Go and Project Setup

Introduction

In this lab you will become familar with Go; go run, go build, go test and the Go environment. In the end, you will understand the project structure for a Go project.

  • Go run, Go doc, Go build
  • Go project Makefile
  • Go linting introduction
  • Go Project structure

References

Getting Familar with Go

1. Go Version

go version

2. Go Env

echo $GOPATH echo $GOROOT echo $GOBIN

3. Go Build / Run

create a simple go file in a random location

foo.go

package main

import (
	"fmt"
)

func main() {
	fmt.Println("hello")
}

Run the program: go run foo.go Build the program: go build foo.go Run the created application: ./foo

4. GoDoc

What is fmt? go doc fmt What is the difference between fmt.Println and fmt.Printf? go doc fmt Println or go doc fmt.Printf

5. Change the main app to take an argument and print hello using Printf.

hint: os.Args is when to get arguments

    argsWithProg := os.Args
    argsWithoutProg := os.Args[1:]

you should be able to test with go run foo.go Ken with an output of Hello Ken!

6. Editor

Download an editor.

If you have vscode, you will need to add the go extensions

7. Lets create a Go project called wman (weather man)

The "Go Way" is within GOPATH where the project is part of the src tree. However Go modules made it possible to leave outside the GOPATH. The "Go Way" is also to include the full version code path as well. Assuming the company codementor on github, than github.com/codementor/<project_name> is the way to go.

You have a couple of options:

  • create under GOPATH: mkdir -p $GOPATH/src/github.com/codementor/wman or
  • mkdir -p github.com/codementor/wman whenever

The path you choose has consequences... next cd to the directory created ex. cd $GOPATH/src/github.com/codementor/wman

Create cmd and pkg folders: mkdir -p cmd/wman and mkdir pkg

Move or recreate your foo.go in the "cmd/wman" folder with the name main.go

Initialize your Go project with Go Modules: go mod init. If you have your project in the $GOTPATH that is all you need. If you placed your project in a location other than GOPATH, then you will need: go mod init github.com/codementor/wman.

From the project root, run the project: go run cmd/wman/main.go foo From the project root, build the project: go build -o bin/wman ./cmd/wman/main.go From the project root, test the project: go test pkg/...

8. Adding a Linter

Download a linter: go get github.com/golangci/golangci-lint/cmd/[email protected]

Lets add linting (it will make you a better go dev!) Create a file: .golangci.yml adding:

linters:
  auto-fix: false
  enable:
    - errcheck
    - goimports
    - golint
    - gosec
    - misspell
    - scopelint
    - unconvert
    - unparam
    - nakedret
    - gocyclo
    - dupl
    - goconst
    - lll
linters-settings:
  errcheck:
    check-type-assertions: true
  lll:
    line-length: 250
  dupl:
    threshold: 400
  goimports:
    # Choose your own project owner for <codementor>
    local-prefixes: github.com/codementor

Run the linter: golangci-lint run

9. Create a Makefile

Lets make a Makefile:

# Run unit tests
.PHONY: test
test:
	go test ./pkg/... 

.PHONY: lint
lint:
	golangci-lint run


.PHONY: cli
# Build CLI
cli:
	go build -o bin/wman ./cmd/wman/main.go

# Install CLI
.PHONY: cli-install
cli-install:
	go install  ./cmd/wman/main.go

.PHONY: run
run:
	go run  ./cmd/wman/main.go

Now build the project with make cli Run make lint

10. Understanding Go Mod

Take a look at your go.mod

Run go mod tidy and take another look cat go.mod

Congratulations! You now have the core of a Go project. Left out are folders such as:

  • internal
  • hack
  • testdata
  • config
  • dist As well as configurations for CI and Release

Lab Solution

https://github.com/codementor/wman/tree/lab1-solution

Clone: git clone -b lab1-solution https://github.com/codementor/wman.git