scope

scope is a substitute for the Go context package.

It provides a more convenient context API than the standard library, while maintaining 100% compatibility.

Requirements

The minimum Go version is go1.26.

Install

The scope package can be added to a project with go get.

go get -u cattlecloud.net/go/scope@latest

Examples

New

ctx:=scope.New()

TTL

ctx, cancel:=scope.TTL(5*time.Second)
// ctx is canceled after 5 secondsdefercancel()

Deadline

ctx, cancel:=scope.Deadline(time.Now().Add(10*time.Second))
// ctx is canceled at the specified timedefercancel()

Cancelable

ctx, cancel:=scope.Cancelable()
// ctx can be canceled manuallydefercancel()

WithCancel

ctx, cancel:=scope.WithCancel(parentCtx)
defercancel()

WithTTL

ctx, cancel:=scope.WithTTL(parentCtx, 3*time.Second)
// parentCtx with a 3 second timeoutdefercancel()

WithValue

ctx:=scope.WithValue(parentCtx, "userID", 123)

Value

userID:=scope.Value[int](ctx, "userID")

Join

ctx1, cancel1:=scope.WithCancel(scope.New())
ctx2, cancel2:=scope.TTL(5*time.Second)
joined, cancel:=scope.Join(ctx1, ctx2)
// joined is canceled when ctx1 or ctx2 is canceleddefercancel()
defercancel1()
defercancel2()

Deadline

ctx1, _:=scope.Deadline(time.Now().Add(10*time.Second))
ctx2, _:=scope.Deadline(time.Now().Add(20*time.Second))
joined, _:=scope.Join(ctx1, ctx2)
deadline, ok:=joined.Deadline() // deadline is 10 seconds, ok is true

Done

joined, cancel:=scope.Join(ctx1, ctx2)
<-joined.Done() // blocks until either ctx1 or ctx2 is done

Err

joined, cancel:=scope.Join(ctx1, ctx2)
<-joined.Done()
err:=joined.Err() // returns the error from the first canceled context

Value

ctx1:=scope.WithValue(scope.New(), "key", "value1")
ctx2:=scope.WithValue(scope.New(), "key", "value2")
joined, _:=scope.Join(ctx1, ctx2)
val:=joined.Value("key") // returns value1 (ctx1's value is checked first)

License

The cattlecloud.net/go/scope module is open source under the BSD license.