Add Close function to Handlers

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Added
+
+- `Close` function to `Handlers`
+
 
 ## [0.21.2] - 2019-07-19
 

handler.go

@@ -2,6 +2,8 @@ package emperror
 
 import (
 	"context"
+
+	"emperror.dev/errors"
 )
 
 // Handler is a generic error handler. It allows applications (and libraries) to handle errors
@@ -23,13 +25,26 @@ type ContextAwareHandler interface {
 type Handlers []Handler
 
 func (h Handlers) Handle(err error) {
+	for _, handler := range h {
+		handler.Handle(err)
+	}
+}
+
+// Close calls Close on the underlying handlers (if there is any closable handler).
+func (h Handlers) Close() error {
 	if len(h) < 1 {
-		return
+		return nil
 	}
 
-	for _, handler := range h {
-		handler.Handle(err)
+	errs := make([]error, len(h))
+
+	for i, handler := range h {
+		if closer, ok := handler.(interface{ Close() error }); ok {
+			errs[i] = closer.Close()
+		}
 	}
+
+	return errors.Combine(errs...)
 }
 
 // HandlerFunc wraps a function and turns it into an error handler.

handler_test.go

@@ -25,6 +25,80 @@ func TestHandlers(t *testing.T) {
 	}
 }
 
+func TestHandlers_NoHandlers(t *testing.T) {
+	var handler Handlers
+
+	err := errors.New("error")
+
+	handler.Handle(err)
+}
+
+type closableHandler struct {
+	handler    Handler
+	closeError error
+}
+
+func (h *closableHandler) Handle(err error) {
+	h.handler.Handle(err)
+}
+
+func (h *closableHandler) Close() error {
+	return h.closeError
+}
+
+func TestHandlers_Close(t *testing.T) {
+	t.Run("no_handlers", func(t *testing.T) {
+		var handler Handlers
+
+		err := handler.Close()
+
+		if err != nil {
+			t.Errorf("unexpected error when closing handlers\nactual:   %+v", err)
+		}
+	})
+
+	t.Run("no_closers", func(t *testing.T) {
+		handler1 := NewTestHandler()
+		handler2 := NewTestHandler()
+
+		handler := Handlers{handler1, handler2}
+
+		err := handler.Close()
+
+		if err != nil {
+			t.Errorf("unexpected error when closing handlers\nactual:   %+v", err)
+		}
+	})
+
+	t.Run("no_errors", func(t *testing.T) {
+		handler1 := &closableHandler{handler: NewTestHandler()}
+		handler2 := NewTestHandler()
+
+		handler := Handlers{handler1, handler2}
+
+		err := handler.Close()
+
+		if err != nil {
+			t.Errorf("unexpected error when closing handlers\nactual:   %+v", err)
+		}
+	})
+
+	t.Run("error", func(t *testing.T) {
+		closeErr := errors.New("close error")
+
+		handler1 := &closableHandler{handler: NewTestHandler(), closeError: closeErr}
+		handler2 := NewTestHandler()
+
+		handler := Handlers{handler1, handler2}
+
+		err := handler.Close()
+
+		if err != closeErr {
+			t.Errorf("unexpected error when closing handlers\nactual:   %#v\nexpected: %#v", err, closeErr)
+		}
+	})
+}
+
 func TestHandlerFunc(t *testing.T) {
 	var actual error
 	log := func(err error) {