added pool watcher capability

1 files changed, 44 insertions, 5 deletions

diff --git a/server.go b/server.go
index 2672a792..397898f2 100644
--- a/server.go
+++ b/server.go
@@ -37,9 +37,13 @@ type Server struct {
 	// creates and connects to workers
 	factory Factory
 
+	// associated pool watcher
+	watcher Watcher
+
 	// currently active pool instance
-	mup  sync.Mutex
-	pool Pool
+	mup      sync.Mutex
+	pool     Pool
+	pWatcher Watcher
 
 	// observes pool events (can be attached to multiple pools at the same time)
 	mul sync.Mutex
@@ -59,6 +63,21 @@ func (s *Server) Listen(l func(event int, ctx interface{})) {
 	s.lsn = l
 }
 
+// Listen attaches server event watcher.
+func (s *Server) Watch(w Watcher) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.watcher = w
+
+	s.mul.Lock()
+	if s.pWatcher != nil && s.pool != nil {
+		s.pWatcher.Detach()
+		s.pWatcher = s.watcher.Attach(s.pool)
+	}
+	s.mul.Unlock()
+}
+
 // Start underlying worker pool, configure factory and command provider.
 func (s *Server) Start() (err error) {
 	s.mu.Lock()
@@ -72,6 +91,10 @@ func (s *Server) Start() (err error) {
 		return err
 	}
 
+	if s.watcher != nil {
+		s.pWatcher = s.watcher.Attach(s.pool)
+	}
+
 	s.pool.Listen(s.poolListener)
 	s.started = true
 	s.throw(EventServerStart, s)
@@ -79,7 +102,7 @@ func (s *Server) Start() (err error) {
 	return nil
 }
 
-// Stop underlying worker pool and close the factory.
+// Detach underlying worker pool and close the factory.
 func (s *Server) Stop() {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -89,6 +112,12 @@ func (s *Server) Stop() {
 	}
 
 	s.throw(EventPoolDestruct, s.pool)
+
+	if s.pWatcher != nil {
+		s.pWatcher.Detach()
+		s.pWatcher = nil
+	}
+
 	s.pool.Destroy()
 	s.factory.Close()
 
@@ -128,6 +157,7 @@ func (s *Server) Reconfigure(cfg *ServerConfig) error {
 
 	s.mu.Lock()
 	previous := s.pool
+	pWatcher := s.pWatcher
 	s.mu.Unlock()
 
 	pool, err := NewPool(cfg.makeCommand(), s.factory, *cfg.Pool)
@@ -139,15 +169,24 @@ func (s *Server) Reconfigure(cfg *ServerConfig) error {
 
 	s.mu.Lock()
 	s.cfg.Pool, s.pool = cfg.Pool, pool
+
+	if s.watcher != nil {
+		s.pWatcher = s.watcher.Attach(pool)
+	}
+
 	s.mu.Unlock()
 
 	s.throw(EventPoolConstruct, pool)
 
 	if previous != nil {
-		go func(previous Pool) {
+		go func(previous Pool, pWatcher Watcher) {
 			s.throw(EventPoolDestruct, previous)
+			if pWatcher != nil {
+				pWatcher.Detach()
+			}
+
 			previous.Destroy()
-		}(previous)
+		}(previous, pWatcher)
 	}
 
 	return nil