Tools Testing

Benchmark code Write benchmark functions with the `Benchmark` prefix and the signature `func BenchmarkXxx(b *testing.B)`, then run them using `go test -bench=. Build CLI with cobra Build a Go CLI with Cobra by installing the CLI generator, initializing a project, adding commands, and building the binary. Build tags in Go Build tags in Go are comments that conditionally include or exclude source files during compilation based on OS, architecture, or custom constraints. CLI with viper config Build a Go CLI by combining Cobra for command parsing with Viper for flexible configuration management. Create and publish module Initialize a module, tag a version in git, and push the tag to publish your Go module. Cross-compile Go for different OS To cross-compile Go for a different operating system or architecture, simply set the `GOOS` and `GOARCH` environment variables before running `go build`, or pass them directly as flags to the compiler. Deploy Go to Kubernetes Deploy Go to Kubernetes by building a Docker image, creating a Deployment manifest, and applying it with kubectl. Docker image for Go app Create a multi-stage Dockerfile to build your Go app in a builder stage and run it in a minimal Alpine image. Environment variables Set the GODEBUG environment variable with key=value pairs to control Go runtime behavior and maintain backwards compatibility. Fuzzing in Go Enable Go fuzzing with the -asan flag and run tests using -test.fuzz to automatically detect memory errors and logic bugs. Go generate code generation Go code generation is handled by the `//go:generate` directive, which allows you to define shell commands that run via `go generate` to create source files from templates or data. go mod tidy vs download go mod tidy cleans your dependency files, while go mod download only fetches modules to the cache. Go vet and staticcheck Run go vet for standard checks and staticcheck for advanced analysis to catch bugs and improve code quality. Go workspaces Go workspaces allow managing multiple modules from a single directory using a go.work file for unified builds and tests. Graceful shutdown Implement graceful shutdown for GOCACHEPROG by handling the 'close' command and exiting after responding. Health checks in K8s Go app Implement a /healthz HTTP endpoint in your Go app and configure Kubernetes probes to monitor container health. How does go mod work `go mod` manages Go modules by tracking dependencies in a `go.mod` file and storing resolved versions in a `go.sum` file to ensure reproducible builds. How to Debug Go Programs with Delve (dlv) Debug Go programs by running `dlv debug` to attach the debugger, set breakpoints, and step through code execution. How to Use golangci-lint for Comprehensive Linting Configure and run golangci-lint with a .golangci.yml file to enforce code quality standards like govet and gofumpt across your Go project. How to Use go tool cover for Test Coverage Run go test -cover to generate data and go tool cover -html to view the report. How to Use go vet for Static Analysis Run `go vet` on your package to detect suspicious constructs like unreachable code, incorrect format strings, and shadowed variables that the compiler misses. How to Use staticcheck for Advanced Static Analysis Install staticcheck via go install and run staticcheck ./... to analyze your Go code for advanced static analysis issues. How to write unit tests Create a _test.go file with Test functions and run go test to verify your code logic. Integration tests Run integration tests by building with coverage flags, executing with GOCOVERDIR, and analyzing results with go tool covdata. Manage dependencies Manage Go dependencies using the go command for version control and govulncheck for security scanning. Mock interfaces Mock interfaces in Go by creating a struct that implements the interface methods to control test behavior and isolate dependencies. Multi-stage Docker build Multi-stage Docker builds separate the compilation process from the runtime environment to create smaller, more secure container images. Private modules Configure private Go modules by setting the GOPRIVATE environment variable to bypass the public proxy for specific import paths. Profile with pprof Profile Go programs by capturing CPU or memory data with runtime/pprof and analyzing it using the pprof tool. Reduce GC pressure GODEBUG settings control runtime feature compatibility and cannot be used to reduce garbage collection pressure or optimize memory usage. Reduce memory allocations Reduce memory allocations by using the arena package to allocate and free memory in bulk, bypassing the garbage collector. Replace directive The `godebug` directive in `go.mod` or `go.work` sets default GODEBUG values to control Go runtime behavior and compatibility. sync Pool for performance Use sync.Pool to cache and reuse objects, reducing allocation overhead and garbage collection pressure. Table-driven tests Table-driven tests use a slice of structs to define multiple test cases and iterate over them in a single function. Test coverage Run go test with the -cover flag to measure code coverage and generate a report. Test HTTP handlers Test HTTP handlers by using httptest.NewRecorder and httptest.NewRequest to simulate requests and verify responses. Use trace tool Control Go runtime behavior and compatibility using GODEBUG environment variables or source file directives. Using testify Use testify's assert or require functions to write clear, concise assertions in your Go unit tests. Vendor dependencies Run go mod vendor to copy all dependencies from go.mod into a local vendor directory for offline builds.