feat(signal): Added Signal Server (#76)

* feat(signal): Added Signal Server

Signed-off-by: Flc゛ <[email protected]>

* feat(signal): Added Signal Server

Signed-off-by: Flc゛ <[email protected]>

* feat(signal): Added Signal Server

Signed-off-by: Flc゛ <[email protected]>

* feat(signal): Added Signal Server

Signed-off-by: Flc゛ <[email protected]>

---------

Signed-off-by: Flc゛ <[email protected]>

signal/README.md

@@ -0,0 +1,72 @@
+# Signal Server
+
+## Example
+
+```go
+package main
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/go-kratos/kratos/v2"
+
+	"github.com/go-kratos-ecosystem/components/v2/signal"
+)
+
+func main() {
+	app := kratos.New(
+		kratos.Server(newSignalServer()),
+	)
+
+	if err := app.Run(); err != nil {
+		panic(err)
+	}
+}
+
+func newSignalServer() *signal.Server {
+	srv := signal.NewServer(
+		signal.WithRecoveryHandler(signal.DefaultRecoveryHandler),
+	)
+
+	srv.Register(&exampleHandler{}, &example2Handler{})
+
+	return srv
+}
+
+type exampleHandler struct{}
+
+func (h *exampleHandler) Listen() []os.Signal {
+	return []os.Signal{syscall.SIGUSR1, syscall.SIGUSR2}
+}
+
+func (h *exampleHandler) Handle(sig os.Signal) {
+	println("exampleHandler signal:", sig)
+}
+
+type example2Handler struct{}
+
+func (h *example2Handler) Listen() []os.Signal {
+	return []os.Signal{syscall.SIGUSR1}
+}
+
+func (h *example2Handler) Handle(os.Signal) {
+	panic("example2Handler panic")
+}
+```
+
+Send signal:
+
+```bash
+$ kill -SIGUSR2 42750
+$ kill -SIGUSR1 42750
+```
+
+Output:
+
+```bash
+INFO msg=[Signal] server starting
+exampleHandler signal: (0x104ff0240,0x1051875b8)
+exampleHandler signal: (0x104ff0240,0x1051875b0)
+ERROR msg=[Signal] handler panic (user defined signal 1): example2Handler panic
+```

signal/handler.go

@@ -0,0 +1,10 @@
+package signal
+
+import (
+	"os"
+)
+
+type Handler interface {
+	Listen() []os.Signal
+	Handle(os.Signal)
+}

signal/server.go

@@ -0,0 +1,123 @@
+package signal
+
+import (
+	"context"
+	"os"
+	"os/signal"
+
+	"github.com/go-kratos/kratos/v2/log"
+)
+
+var DefaultRecoveryHandler = func(err interface{}, sig os.Signal, handler Handler) {
+	log.Errorf("[Signal] handler panic (%s): %v", sig, err)
+}
+
+type Server struct {
+	handlers        []Handler
+	stoped          chan struct{}
+	recoveryHandler func(interface{}, os.Signal, Handler)
+}
+
+type Option func(*Server)
+
+func AddHandler(handler ...Handler) Option {
+	return func(s *Server) {
+		s.handlers = append(s.handlers, handler...)
+	}
+}
+
+func WithRecoveryHandler(handler func(interface{}, os.Signal, Handler)) Option {
+	return func(s *Server) {
+		if handler != nil {
+			s.recoveryHandler = handler
+		}
+	}
+}
+
+func NewServer(opts ...Option) *Server {
+	server := &Server{
+		handlers: make([]Handler, 0),
+		stoped:   make(chan struct{}),
+	}
+
+	for _, opt := range opts {
+		opt(server)
+	}
+
+	if server.recoveryHandler == nil {
+		server.recoveryHandler = DefaultRecoveryHandler
+	}
+
+	return server
+}
+
+func (s *Server) Start(ctx context.Context) error {
+	var (
+		signals  = make([]os.Signal, 0)
+		handlers = make(map[os.Signal][]Handler)
+	)
+
+	for _, h := range s.handlers {
+		for _, sig := range h.Listen() {
+			if _, ok := handlers[sig]; !ok {
+				handlers[sig] = make([]Handler, 0)
+			}
+			handlers[sig] = append(handlers[sig], h)
+		}
+		signals = append(signals, h.Listen()...)
+	}
+
+	signals = s.uniqueSignals(signals)
+
+	ch := make(chan os.Signal, len(signals))
+	signal.Notify(ch, signals...)
+
+	log.Infof("[Signal] server starting")
+
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-s.stoped:
+			return nil
+		case sig := <-ch:
+			if hs, ok := handlers[sig]; ok {
+				for _, h := range hs {
+					s.handle(sig, h)
+				}
+			}
+		}
+	}
+}
+
+func (s *Server) Register(handlers ...Handler) {
+	s.handlers = append(s.handlers, handlers...)
+}
+
+func (s *Server) Stop(context.Context) error {
+	log.Infof("[Signal] server stopping")
+	close(s.stoped)
+	return nil
+}
+
+func (s *Server) handle(sig os.Signal, handler Handler) {
+	defer func() {
+		if err := recover(); err != nil {
+			s.recoveryHandler(err, sig, handler)
+		}
+	}()
+
+	handler.Handle(sig)
+}
+
+func (s *Server) uniqueSignals(signals []os.Signal) []os.Signal {
+	m := make(map[os.Signal]struct{})
+	for _, sig := range signals {
+		m[sig] = struct{}{}
+	}
+	signals = make([]os.Signal, 0)
+	for sig := range m {
+		signals = append(signals, sig)
+	}
+	return signals
+}

signal/server_test.go

@@ -0,0 +1,77 @@
+package signal
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"sync"
+	"syscall"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	buffer bytes.Buffer
+	mu     sync.Mutex
+)
+
+func TestServer(t *testing.T) {
+	srv := newServer()
+
+	go srv.Start(context.Background()) //nolint:errcheck
+
+	time.Sleep(2 * time.Second)
+
+	assert.NoError(t, syscall.Kill(os.Getpid(), syscall.SIGUSR1))
+	assert.NoError(t, syscall.Kill(os.Getpid(), syscall.SIGUSR2))
+
+	time.Sleep(2 * time.Second)
+
+	mu.Lock()
+	assert.Equal(t, `exampleHandler signal: user defined signal 1
+signal: user defined signal 1, handler: *signal.example2Handler, err: example2Handler panic
+exampleHandler signal: user defined signal 2
+`, buffer.String())
+	mu.Unlock()
+
+	srv.Stop(context.Background()) //nolint:errcheck
+}
+
+func newServer() *Server {
+	srv := NewServer(
+		WithRecoveryHandler(func(err interface{}, signal os.Signal, handler Handler) {
+			mu.Lock()
+			defer mu.Unlock()
+			buffer.WriteString(fmt.Sprintf("signal: %s, handler: %T, err: %v\n", signal, handler, err))
+		}),
+	)
+
+	srv.Register(&exampleHandler{}, &example2Handler{})
+
+	return srv
+}
+
+type exampleHandler struct{}
+
+func (h *exampleHandler) Listen() []os.Signal {
+	return []os.Signal{syscall.SIGUSR1, syscall.SIGUSR2}
+}
+
+func (h *exampleHandler) Handle(sig os.Signal) {
+	mu.Lock()
+	defer mu.Unlock()
+	buffer.WriteString(fmt.Sprintf("exampleHandler signal: %s\n", sig))
+}
+
+type example2Handler struct{}
+
+func (h *example2Handler) Listen() []os.Signal {
+	return []os.Signal{syscall.SIGUSR1}
+}
+
+func (h *example2Handler) Handle(os.Signal) {
+	panic("example2Handler panic")
+}