Go's switch statement will not be executed throughout the process by default and will automatically exit after matching the first condition. 1. Switch starts with a keyword and can carry one or no value; 2. Case matches from top to bottom in order, only the first match is run; 3. Multiple conditions can be listed by commas to match the same case; 4. There is no need to manually add break, but can be forced through; 5.default is used for unmatched cases, usually placed at the end.

In Go, to break out of nested loops, you should use labeled break statements or return through functions; 1. Use labeled break: Place the tag before the outer loop, such as OuterLoop:for{...}, use breakOuterLoop in the inner loop to directly exit the outer loop; 2. Put the nested loop into the function, and return in advance when the conditions are met, thereby terminating all loops; 3. Avoid using flag variables or goto, the former is lengthy and easy to make mistakes, and the latter is not recommended; the correct way is that the tag must be before the loop rather than after it, which is the idiomatic way to break out of multi-layer loops in Go.

Usecontexttopropagatecancellationanddeadlinesacrossgoroutines,enablingcooperativecancellationinHTTPservers,backgroundtasks,andchainedcalls.2.Withcontext.WithCancel(),createacancellablecontextandcallcancel()tosignaltermination,alwaysdeferringcancel()t

Use a dedicated and reasonably configured HTTP client to set timeout and connection pools to improve performance and resource utilization; 2. Implement a retry mechanism with exponential backoff and jitter, only retry for 5xx, network errors and 429 status codes, and comply with Retry-After headers; 3. Use caches for static data such as user information (such as sync.Map or Redis), set reasonable TTL to avoid repeated requests; 4. Use semaphore or rate.Limiter to limit concurrency and request rates to prevent current limit or blocking; 5. Encapsulate the API as an interface to facilitate testing, mocking, and adding logs, tracking and other middleware; 6. Monitor request duration, error rate, status code and retry times through structured logs and indicators, combined with Op

To correctly copy slices in Go, you must create a new underlying array instead of directly assigning values; 1. Use make and copy functions: dst:=make([]T,len(src));copy(dst,src); 2. Use append and nil slices: dst:=append([]T(nil),src...); both methods can realize element-level copying, avoid sharing the underlying array, and ensure that modifications do not affect each other. Direct assignment of dst=src will cause both to refer to the same array and are not real copying.

Go uses time.Time structure to process dates and times, 1. Format and parse the reference time "2006-01-0215:04:05" corresponding to "MonJan215:04:05MST2006", 2. Use time.Date(year, month, day, hour, min, sec, nsec, loc) to create the date and specify the time zone such as time.UTC, 3. Time zone processing uses time.LoadLocation to load the position and use time.ParseInLocation to parse the time with time zone, 4. Time operation uses Add, AddDate and Sub methods to add and subtract and calculate the interval.

Use the template.ParseFS and embed package to compile HTML templates into binary files. 1. Import the embed package and embed the template file into the embed.FS variable with //go:embedtemplates/.html; 2. Call template.Must(template.ParseFS(templateFS,"templates/.html")))) to parse all matching template files; 3. Render the specified in the HTTP processor through tmpl.ExecuteTemplate(w,"home.html", nil)

To import local packages correctly, you need to use the Go module and follow the principle of matching directory structure with import paths. 1. Use gomodinit to initialize the module, such as gomodinitexample.com/myproject; 2. Place the local package in a subdirectory, such as mypkg/utils.go, and the package is declared as packagemypkg; 3. Import it in main.go through the full module path, such as import "example.com/myproject/mypkg"; 4. Avoid relative import, path mismatch or naming conflicts; 5. Use replace directive for packages outside the module. Just make sure the module is initialized