Go Toolchain

Go comes with an integrated toolchain for formatting, linting, testing, building, and deployment. No complex configuration needed -> these tools work out of the box. This creates a consistent development experience and reduces configuration decisions.

go fmt / gofmt — Code Formatting

go fmt automatically formats Go code according to standard Go style. No debates about rules -> the tool decides. Gofmt is the underlying tool; go fmt is a convenient wrapper. Run go fmt ./... to format your entire project.

Terminal

1// Unformatted code2func   Add(a,b   int)int{3return a+b4}56// After 'go fmt':7func Add(a, b int) int {8	return a + b9}1011// Run formatting12go fmt ./...           // format all packages13gofmt -w main.go       // format and write to file14gofmt -l ./...         // list files that need formatting

Tip

Most Go IDE/editors integrate go fmt and run it automatically when you save a file. This means you never have to worry about running it manually.

go vet — Static Analysis

go vet checks code for common errors the compiler misses: incorrect Printf format verb usage, unreachable code, common mistake patterns. Run go vet ./... frequently, especially before committing.

main.go

1// Bad code that vet catches2package main34import "fmt"56func main() {7	// Wrong format verb for string8	name := "Alice"9	fmt.Printf("%d\n", name)  // vet warns: %d expects int1011	// Unreachable code12	if true {

go test — Running Tests

go test finds and runs all test functions in *_test.go files. Important flags: -v (verbose), -run (filter tests), -race (detect data races), -bench (run benchmarks), -cover (code coverage).

Terminal

1// Run tests2go test ./...                        // test all packages3go test -v ./...                     // verbose output45// Filter tests6go test -run TestAdd ./...           // run tests matching 'TestAdd'7go test -run TestAdd/positive ./...  // run TestAdd/positive subtest89// Race detection10go test -race ./...                  // detect concurrent access to shared memory1112// Benchmarks

go build and go install — Compilation

go build compiles code to a binary without installing. go install compiles and saves the binary to $GOBIN. Use GOOS and GOARCH env vars to cross-compile for other platforms. Flags like -ldflags let you inject version/build info.

Terminal

1// Build2go build ./...                 // build all packages3go build -o myapp ./cmd/app   // build with specific output name4go build -o . ./...            // build all packages in current dir56// Install (binary goes to $GOBIN)7go install ./...               // install all packages8go install ./cmd/app           // install specific package910// Cross-compilation11GOOS=linux GOARCH=amd64 go build ./...        // Linux 64-bit12GOOS=darwin GOARCH=arm64 go build ./...       // macOS ARM (M1)

Tip

Cross-compilation in Go is easy because there are no C dependencies by default. You can compile for Linux from macOS or Windows without any special setup.

go mod — Module Management

go mod manages your project's dependencies. The go.mod file stores dependencies and their versions. go mod tidy adds missing dependencies and removes unused ones. go mod vendor copies dependencies into vendor/. go mod graph displays the dependency tree.

Terminal

1// Initialize module2go mod init github.com/user/myapp34// Add dependency (automatic when used in code)5go get github.com/gorilla/mux@v1.8.06go get github.com/lib/pq                  // latest version78// Update dependencies9go mod tidy                               // add missing, remove unused10go mod tidy -v                            // verbose1112// Vendor dependencies (copy to vendor/)

golangci-lint — Linter Aggregator

golangci-lint is an aggregator of linters. Instead of running linters separately, golangci-lint runs them all at once. Configure via .golangci.yml. Popular linters: errcheck (unchecked errors), staticcheck (bug detection), gosimple (code simplification).

.golangci.yml

1// Install golangci-lint2curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin34// Run all linters5golangci-lint run ./...67// Run specific linter8golangci-lint run --disable-all -E errcheck ./...910// Fix issues (if possible)11golangci-lint run --fix ./...12

go generate — Code Generation

Directives //go:generate let you run tools to generate code. Use cases: stringer (generate String() method), protobuf (generate from .proto files), mockery (generate mocks). Run go generate ./... to execute all directives.

main.go

1package main23import "fmt"45//go:generate stringer -type=Color67type Color int89const (10	Red Color = iota11	Green12	Blue

Go Workspaces

go.work file lets you work with multiple modules at once. Useful for monorepos or when developing a library alongside an app. go work init creates the file. go work use -r ./... adds all modules.

Terminal

1// Create workspace2go work init ./mylib ./myapp34// go.work file5go 1.2167use (8	./mylib9	./myapp10)1112// Add modules13go work use -r ./...1415// Remove module16go work edit -dropuse ./oldmodule1718// View workspace19cat go.work

Key Takeaways

Điểm Chính

go fmt automatically formats code, making style debates unnecessarygo fmt tự động định dạng code, làm cho tranh cãi về style không cần thiết
go test -race detects concurrent access to shared memorygo test -race phát hiện truy cập đồng thời vào bộ nhớ dùng chung
Cross-compilation is simple with GOOS and GOARCH environment variablesCross-compilation rất đơn giản với các biến môi trường GOOS và GOARCH
golangci-lint aggregates multiple linters for comprehensive code checkinggolangci-lint tập hợp nhiều linter để kiểm tra code toàn diện

Practice

Test your understanding of this chapter

Quiz

What is the difference between go build and go install?

Sự khác biệt giữa go build và go install là gì?

Quiz

How do you cross-compile a Go program for Linux from macOS?

Làm thế nào để cross-compile chương trình Go cho Linux từ macOS?

True or False

go vet is built into Go and can detect unused variables, unreachable code, and incorrect Printf format verbs.

go vet được xây dựng trong Go và có thể phát hiện biến không sử dụng, code không thể truy cập và format verb Printf không chính xác.

True or False

golangci-lint replaces the need for go fmt and go vet.

golangci-lint thay thế nhu cầu về go fmt và go vet.

Code Challenge

Fill in the command to update a Go project's dependencies

Điền vào lệnh để cập nhật các dependency của dự án Go

go mod