func Secure() (int64, error) {
var b [8]byte
_, err := crand.Read(b[:])
if err != nil {
return 0, errors.New("cannot seed math/rand package with cryptographically secure random number generator")
}
return int64(binary.LittleEndian.Uint64(b[:])), nil
}
- WithCancel 提供一个可以手动关停的chan，这个chan一旦被关停子线程的chan也会被关掉
oklog/run
run.Group is a universal mechanism to manage goroutine lifecycles.
Create a zero-value run.Group, and then add actors to it. Actors are defined as a pair of functions: an execute function, which should run synchronously; and an interrupt function, which, when invoked, should cause the execute function to return. Finally, invoke Run, which concurrently runs all of the actors, waits until the first actor exits, invokes the interrupt functions, and finally returns control to the caller only once all actors have returned. This general-purpose API allows callers to model pretty much any runnable task, and achieve well-defined lifecycle semantics for the group.
run.Group was written to manage component lifecycles in func main for OK Log. But it's useful in any circumstance where you need to orchestrate multiple goroutines as a unit whole. Click here to see a video of a talk where run.Group is described.
- 概括就是一个开源项目，给每个actor绑定一对函数(execute,interrupt)，方便对一组线程进行生命周期管理
peterbourgon/ff
ff stands for flags-first, and provides an opinionated way to populate a flag.FlagSet with configuration data from the environment. By default, it parses only from the command line, but you can enable parsing from environment variables (lower priority) and/or a configuration file (lowest priority).
Building a commandline application in the style of kubectl or docker? Consider package ffcli, a natural companion to, and extension of, package ff.
ff.Parse(fs, os.Args[1:],
ff.WithEnvVarPrefix("MY_PROGRAM"),
ff.WithConfigFileFlag("config"),
ff.WithConfigFileParser(ff.PlainParser),
)
Additionally, the example will look in the environment for variables with a MY_PROGRAM prefix. Flag names are capitalized, and separator characters are converted to underscores. In this case, for example, MY_PROGRAM_LISTEN_ADDR would match to listen-addr.
- 参数解析扩展，不止从命令行获取，还会低优先级去访问诸如环境变量、配置文件