When will golang defer be executed?

Go's flag package is a standard way to handle command line parameters and is suitable for writing CLI tools. 1. Use flag.String, flag.Int, flag.Bool to define flags and return pointers, or use flag.StringVar and flag.BoolVar to bind values to variables; 2. You must call flag.Parse() to analyze parameters before you can use flag values safely; 3. The subcommand needs to be manually implemented through flag.NewFlagSet, create independent FlagSets according to different subcommands and parse corresponding parameters; 4. Non-flag parameters can be obtained through flag.Args(); 5. Automatically support -h or --help to display help information; 6

Go supports cross-platform compilation without external tools. By setting GOOS and GOARCH environment variables, you can generate binary files of the target platform; 1. Use GOOS to specify the target operating system (such as linux, windows, darwin), and GOARCH specifies the CPU architecture (such as amd64, arm64); 2. For ARM platforms, you need to set additional GOARM versions (such as GOARM=7); 3. It is recommended to set CGO_ENABLED=0 to generate statically linked independent binary files to avoid relying on system libraries; 4. Pay attention to avoid using CGO, handle the compatibility between paths and system calls, and correctly manage embedded resource paths; 5. Cannot run programs that are not natively architecture locally.

In Go language, the scenarios of using pointers mainly include the following situations: 1. When you want the function to modify external variables, you should use a pointer, because Go is a value-passing language, and the function operates internally is a copy; 2. When processing larger structures or arrays, passing pointers can save memory and improve performance, because they only copy addresses rather than the entire data; 3. When defining a method, if you need to modify the receiver status, you should use a pointer receiver, otherwise the method will only act on the copy; 4. Use a pointer field to represent the "unset" state, such as setting time.Time to nil to distinguish whether the birthday is set. Rational use of pointers can improve code efficiency and semantic clarity.

Clarify service boundaries and focus on a single business capability (such as user-service only cares about user profile); 2. Prioritize the use of net/http or lightweight frameworks such as Gin/Chi to avoid premature complicating; 3. Organize code in layers according to /cmd, /internal, /pkg, etc. to improve maintainability; 4. Use environment variables to configure and tool-manage keys (such as Vault), and never submit .env to Git; 5. Early integration/healthz health checks, structured logs and request ID tracking; 6. Unit tests cover business logic, table-driven tests to reduce redundancy; 7. Docker builds images in multiple stages, locally use docker-compose, and choose K8s or Fl for production

Static analysis and Linter can make up for the shortcomings of gofmt and govet. Through tools such as golangci-lint, various inspection methods are integrated, 1. Achieve code style uniformity, 2. Detect potential bugs, 3. Provide performance optimization suggestions, 4. Discover security vulnerabilities, 5. Support CI/CD automation verification, and the enabled linter should be configured reasonably during use, and staticcheck, errcheck, revive and gosec are preferred, and combined with pre-commit and CI processes to continuously improve the code quality is an indispensable practice for modern Go projects.

In Go, base64 encoding requires selecting the appropriate encoding method according to the scene: 1. Use base64.StdEncoding in ordinary text, HTTP, and JSON; 2. Use base64.URLEncoding in URL, file name, and JWT to avoid special character problems; 3. Use base64.RawStdEncoding or RawURLEncoding when there is no fill format; encoding and decoding can be completed through EncodeToString and DecodeString methods. The standard library supports complete and simple to use, which can meet daily development needs.

Theinit()functioninGoisusedtoperformsetuptasksbeforethemainfunctionruns.Itisautomaticallycalledwhenapackageisinitialized,aftervariabledeclarationsbutbeforemain().1.Ithelpssetupdatabaseconnections,registerHTTPhandlers,initializeglobalvariables,andpars

When checking whether the key exists in the map in Go, you must use the double-value return form to accurately judge the existence of the key. 1. Use value, ok:=myMap[key] to obtain the value and the existence flag. 2. Use the ok boolean value to determine whether the key exists. If true, the key exists and the value can be safely used. Otherwise, the key does not exist. This method can effectively distinguish between zero values and missing keys, which is a safe standard practice for processing mapping searches.