mirror of https://github.com/prometheus/prometheus
74 lines
2.2 KiB
Markdown
74 lines
2.2 KiB
Markdown
# run
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[](https://godoc.org/github.com/oklog/run)
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[](https://travis-ci.org/oklog/run)
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[](https://goreportcard.com/report/github.com/oklog/run)
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[](https://raw.githubusercontent.com/oklog/run/master/LICENSE)
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run.Group is a universal mechanism to manage goroutine lifecycles.
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Create a zero-value run.Group, and then add actors to it. Actors are defined as
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a pair of functions: an **execute** function, which should run synchronously;
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and an **interrupt** function, which, when invoked, should cause the execute
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function to return. Finally, invoke Run, which blocks until the first actor
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returns. This general-purpose API allows callers to model pretty much any
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runnable task, and achieve well-defined lifecycle semantics for the group.
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run.Group was written to manage component lifecycles in func main for
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[OK Log](https://github.com/oklog/oklog).
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But it's useful in any circumstance where you need to orchestrate multiple
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goroutines as a unit whole.
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[Click here](https://www.youtube.com/watch?v=LHe1Cb_Ud_M&t=15m45s) to see a
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video of a talk where run.Group is described.
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## Examples
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### context.Context
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```go
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ctx, cancel := context.WithCancel(context.Background())
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g.Add(func() error {
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return myProcess(ctx, ...)
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}, func(error) {
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cancel()
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})
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```
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### net.Listener
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```go
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ln, _ := net.Listen("tcp", ":8080")
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g.Add(func() error {
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return http.Serve(ln, nil)
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}, func(error) {
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ln.Close()
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})
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```
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### io.ReadCloser
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```go
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var conn io.ReadCloser = ...
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g.Add(func() error {
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s := bufio.NewScanner(conn)
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for s.Scan() {
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println(s.Text())
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}
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return s.Err()
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}, func(error) {
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conn.Close()
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})
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```
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## Comparisons
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Package run is somewhat similar to package
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[errgroup](https://godoc.org/golang.org/x/sync/errgroup),
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except it doesn't require actor goroutines to understand context semantics.
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It's somewhat similar to package
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[tomb.v1](https://godoc.org/gopkg.in/tomb.v1) or
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[tomb.v2](https://godoc.org/gopkg.in/tomb.v2),
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except it has a much smaller API surface, delegating e.g. staged shutdown of
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goroutines to the caller.
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