coredns/plugin/pkg/uniq/uniq.go
Zach Eddy 8aa55c5ff2 Metrics listener fix (#2036)
* Create test to verify correct listener behavior

* Create Unset function to remove todo items

* Reset address for prometheus listener before restarting

* Add inline documentation for Unset function

* Make shutdownTimeout a constant and change to five seconds

* Revert ForEach behavior in uniq package
2018-08-21 11:52:25 -04:00

59 lines
1.1 KiB
Go

// Package uniq keeps track of "thing" that are either "todo" or "done". Multiple
// identical events will only be processed once.
package uniq
// U keeps track of item to be done.
type U struct {
u map[string]item
}
type item struct {
state int // either todo or done
f func() error // function to be executed.
}
// New returns a new initialized U.
func New() U { return U{u: make(map[string]item)} }
// Set sets function f in U under key. If the key already exists
// it is not overwritten.
func (u U) Set(key string, f func() error) {
if _, ok := u.u[key]; ok {
return
}
u.u[key] = item{todo, f}
}
// Unset removes the 'todo' associated with a key
func (u U) Unset(key string) {
if _, ok := u.u[key]; ok {
delete(u.u, key)
}
}
// SetTodo sets key to 'todo' again.
func (u U) SetTodo(key string) {
v, ok := u.u[key]
if !ok {
return
}
v.state = todo
u.u[key] = v
}
// ForEach iterates for u executes f for each element that is 'todo' and sets it to 'done'.
func (u U) ForEach() error {
for k, v := range u.u {
if v.state == todo {
v.f()
}
v.state = done
u.u[k] = v
}
return nil
}
const (
todo = 1
done = 2
)