refactor code for context fallthrough

pkg/metrics/server.go

@@ -14,7 +14,6 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 
 	"github.com/sot-tech/mochi/pkg/log"
-	"github.com/sot-tech/mochi/pkg/stop"
 )
 
 const (
@@ -50,14 +49,9 @@ func AddressFamily(ip netip.Addr) string {
 	}
 }
 
-// Stop shuts down the server.
-func (s *Server) Stop() stop.Result {
-	c := make(stop.Channel)
-	go func() {
-		c.Done(s.srv.Shutdown(context.Background()))
-	}()
-
-	return c.Result()
+// Close shuts down the server.
+func (s *Server) Close() error {
+	return s.srv.Shutdown(context.Background())
 }
 
 // NewServer creates a new instance of a Prometheus server that asynchronously

pkg/stop/stop.go

@@ -1,125 +0,0 @@
-// Package stop implements a pattern for shutting down a group of processes.
-package stop
-
-import (
-	"sync"
-)
-
-// Channel is used to return zero or more errors asynchronously. Call Done()
-// once to pass errors to the Channel.
-type Channel chan []error
-
-// Result is a receive-only version of Channel. Call Wait() once to receive any
-// returned errors.
-type Result <-chan []error
-
-// Done adds zero or more errors to the Channel and closes it, indicating the
-// caller has finished stopping. It should be called exactly once.
-func (ch Channel) Done(errs ...error) {
-	if len(errs) > 0 && errs[0] != nil {
-		ch <- errs
-	}
-	close(ch)
-}
-
-// Result converts a Channel to a Result.
-func (ch Channel) Result() <-chan []error {
-	return ch
-}
-
-// Wait blocks until Done() is called on the underlying Channel and returns any
-// errors. It should be called exactly once.
-func (r Result) Wait() []error {
-	return <-r
-}
-
-// AlreadyStopped is a closed error channel to be used by Funcs when
-// an element was already stopped.
-var AlreadyStopped Result
-
-// AlreadyStoppedFunc is a Func that returns AlreadyStopped.
-var AlreadyStoppedFunc = func() Result { return AlreadyStopped }
-
-func init() {
-	closeMe := make(Channel)
-	close(closeMe)
-	AlreadyStopped = closeMe.Result()
-}
-
-// Stopper is an interface that allows a clean shutdown.
-type Stopper interface {
-	// Stop returns a channel that indicates whether the stop was
-	// successful.
-	//
-	// The channel can either return one error or be closed.
-	// Closing the channel signals a clean shutdown.
-	// Stop() should return immediately and perform the actual shutdown in a
-	// separate goroutine.
-	Stop() Result
-}
-
-// Func is a function that can be used to provide a clean shutdown.
-type Func func() Result
-
-// Group is a collection of Stoppers that can be stopped all at once.
-type Group struct {
-	stoppables []Func
-	sync.Mutex
-}
-
-// NewGroup allocates a new Group.
-func NewGroup() *Group {
-	return &Group{
-		stoppables: make([]Func, 0),
-	}
-}
-
-// Add appends a Stopper to the Group.
-func (cg *Group) Add(toAdd Stopper) {
-	cg.Lock()
-	defer cg.Unlock()
-
-	cg.stoppables = append(cg.stoppables, toAdd.Stop)
-}
-
-// AddFunc appends a Func to the Group.
-func (cg *Group) AddFunc(toAddFunc Func) {
-	cg.Lock()
-	defer cg.Unlock()
-
-	cg.stoppables = append(cg.stoppables, toAddFunc)
-}
-
-// Stop stops all members of the Group.
-//
-// Stopping will be done in a concurrent fashion.
-// The slice of errors returned contains all errors returned by stopping the
-// members.
-func (cg *Group) Stop() Result {
-	cg.Lock()
-	defer cg.Unlock()
-
-	whenDone := make(Channel)
-
-	waitChannels := make([]Result, 0, len(cg.stoppables))
-	for _, toStop := range cg.stoppables {
-		waitFor := toStop()
-		if waitFor == nil {
-			panic("received a nil chan from Stop")
-		}
-		waitChannels = append(waitChannels, waitFor)
-	}
-
-	go func() {
-		var errors []error
-		for _, waitForMe := range waitChannels {
-			childErrors := waitForMe.Wait()
-			if len(childErrors) > 0 {
-				errors = append(errors, childErrors...)
-			}
-		}
-		whenDone.Done(errors...)
-	}()
-
-	return whenDone.Result()
-}