Add support for HandlerList.PushBackNamed()/PushFrontNamed()

Also adds HandlerList.Remove() which allows removal of NamedHandlers.

aws/corehandlers/handlers.go

@@ -23,7 +23,7 @@ type lener interface {
 // BuildContentLength builds the content length of a request based on the body,
 // or will use the HTTPRequest.Header's "Content-Length" if defined. If unable
 // to determine request body length and no "Content-Length" was specified it will panic.
-func BuildContentLength(r *request.Request) {
+var BuildContentLengthHandler = request.NamedHandler{"core.BuildContentLengthHandler", func(r *request.Request) {
 	if slength := r.HTTPRequest.Header.Get("Content-Length"); slength != "" {
 		length, _ := strconv.ParseInt(slength, 10, 64)
 		r.HTTPRequest.ContentLength = length
@@ -47,17 +47,17 @@ func BuildContentLength(r *request.Request) {
 
 	r.HTTPRequest.ContentLength = length
 	r.HTTPRequest.Header.Set("Content-Length", fmt.Sprintf("%d", length))
-}
+}}
 
 // UserAgentHandler is a request handler for injecting User agent into requests.
-func UserAgentHandler(r *request.Request) {
+var UserAgentHandler = request.NamedHandler{"core.UserAgentHandler", func(r *request.Request) {
 	r.HTTPRequest.Header.Set("User-Agent", aws.SDKName+"/"+aws.SDKVersion)
-}
+}}
 
 var reStatusCode = regexp.MustCompile(`^(\d{3})`)
 
 // SendHandler is a request handler to send service request using HTTP client.
-func SendHandler(r *request.Request) {
+var SendHandler = request.NamedHandler{"core.SendHandler", func(r *request.Request) {
 	var err error
 	r.HTTPResponse, err = r.Service.Config.HTTPClient.Do(r.HTTPRequest)
 	if err != nil {
@@ -89,19 +89,19 @@ func SendHandler(r *request.Request) {
 		r.Error = awserr.New("RequestError", "send request failed", err)
 		r.Retryable = aws.Bool(true) // network errors are retryable
 	}
-}
+}}
 
 // ValidateResponseHandler is a request handler to validate service response.
-func ValidateResponseHandler(r *request.Request) {
+var ValidateResponseHandler = request.NamedHandler{"core.ValidateResponseHandler", func(r *request.Request) {
 	if r.HTTPResponse.StatusCode == 0 || r.HTTPResponse.StatusCode >= 300 {
 		// this may be replaced by an UnmarshalError handler
 		r.Error = awserr.New("UnknownError", "unknown error", nil)
 	}
-}
+}}
 
 // AfterRetryHandler performs final checks to determine if the request should
 // be retried and how long to delay.
-func AfterRetryHandler(r *request.Request) {
+var AfterRetryHandler = request.NamedHandler{"core.AfterRetryHandler", func(r *request.Request) {
 	// If one of the other handlers already set the retry state
 	// we don't want to override it based on the service's state
 	if r.Retryable == nil {
@@ -123,15 +123,15 @@ func AfterRetryHandler(r *request.Request) {
 		r.RetryCount++
 		r.Error = nil
 	}
-}
+}}
 
 // ValidateEndpointHandler is a request handler to validate a request had the
 // appropriate Region and Endpoint set. Will set r.Error if the endpoint or
 // region is not valid.
-func ValidateEndpointHandler(r *request.Request) {
+var ValidateEndpointHandler = request.NamedHandler{"core.ValidateEndpointHandler", func(r *request.Request) {
 	if r.Service.SigningRegion == "" && aws.StringValue(r.Service.Config.Region) == "" {
 		r.Error = aws.ErrMissingRegion
 	} else if r.Service.Endpoint == "" {
 		r.Error = aws.ErrMissingEndpoint
 	}
-}
+}}

aws/corehandlers/handlers_test.go

@@ -20,7 +20,7 @@ func TestValidateEndpointHandler(t *testing.T) {
 	os.Clearenv()
 	svc := service.New(aws.NewConfig().WithRegion("us-west-2"))
 	svc.Handlers.Clear()
-	svc.Handlers.Validate.PushBack(corehandlers.ValidateEndpointHandler)
+	svc.Handlers.Validate.PushBackNamed(corehandlers.ValidateEndpointHandler)
 
 	req := svc.NewRequest(&request.Operation{Name: "Operation"}, nil, nil)
 	err := req.Build()
@@ -32,7 +32,7 @@ func TestValidateEndpointHandlerErrorRegion(t *testing.T) {
 	os.Clearenv()
 	svc := service.New(nil)
 	svc.Handlers.Clear()
-	svc.Handlers.Validate.PushBack(corehandlers.ValidateEndpointHandler)
+	svc.Handlers.Validate.PushBackNamed(corehandlers.ValidateEndpointHandler)
 
 	req := svc.NewRequest(&request.Operation{Name: "Operation"}, nil, nil)
 	err := req.Build()
@@ -68,7 +68,7 @@ func TestAfterRetryRefreshCreds(t *testing.T) {
 	svc.Handlers.UnmarshalError.PushBack(func(r *request.Request) {
 		r.Error = awserr.New("ExpiredTokenException", "", nil)
 	})
-	svc.Handlers.AfterRetry.PushBack(corehandlers.AfterRetryHandler)
+	svc.Handlers.AfterRetry.PushBackNamed(corehandlers.AfterRetryHandler)
 
 	assert.True(t, svc.Config.Credentials.IsExpired(), "Expect to start out expired")
 	assert.False(t, credProvider.retrieveCalled)
@@ -97,7 +97,7 @@ func TestSendHandlerError(t *testing.T) {
 		},
 	})
 	svc.Handlers.Clear()
-	svc.Handlers.Send.PushBack(corehandlers.SendHandler)
+	svc.Handlers.Send.PushBackNamed(corehandlers.SendHandler)
 	r := svc.NewRequest(&request.Operation{Name: "Operation"}, nil, nil)
 
 	r.Send()

aws/corehandlers/param_validator.go

@@ -11,7 +11,7 @@ import (
 
 // ValidateParameters is a request handler to validate the input parameters.
 // Validating parameters only has meaning if done prior to the request being sent.
-func ValidateParameters(r *request.Request) {
+var ValidateParametersHandler = request.NamedHandler{"core.ValidateParametersHandler", func(r *request.Request) {
 	if r.ParamsFilled() {
 		v := validator{errors: []string{}}
 		v.validateAny(reflect.ValueOf(r.Params), "")
@@ -22,7 +22,7 @@ func ValidateParameters(r *request.Request) {
 			r.Error = awserr.New("InvalidParameter", msg, nil)
 		}
 	}
-}
+}}
 
 // A validator validates values. Collects validations errors which occurs.
 type validator struct {

aws/corehandlers/param_validator_test.go

@@ -56,14 +56,14 @@ func TestNoErrors(t *testing.T) {
 	}
 
 	req := testSvc.NewRequest(&request.Operation{}, input, nil)
-	corehandlers.ValidateParameters(req)
+	corehandlers.ValidateParametersHandler.Fn(req)
 	assert.NoError(t, req.Error)
 }
 
 func TestMissingRequiredParameters(t *testing.T) {
 	input := &StructShape{}
 	req := testSvc.NewRequest(&request.Operation{}, input, nil)
-	corehandlers.ValidateParameters(req)
+	corehandlers.ValidateParametersHandler.Fn(req)
 
 	assert.Error(t, req.Error)
 	assert.Equal(t, "InvalidParameter", req.Error.(awserr.Error).Code())
@@ -82,7 +82,7 @@ func TestNestedMissingRequiredParameters(t *testing.T) {
 	}
 
 	req := testSvc.NewRequest(&request.Operation{}, input, nil)
-	corehandlers.ValidateParameters(req)
+	corehandlers.ValidateParametersHandler.Fn(req)
 
 	assert.Error(t, req.Error)
 	assert.Equal(t, "InvalidParameter", req.Error.(awserr.Error).Code())

aws/request/handlers.go

@@ -47,39 +47,66 @@ func (h *Handlers) Clear() {
 
 // A HandlerList manages zero or more handlers in a list.
 type HandlerList struct {
-	list []func(*Request)
+	list []NamedHandler
+}
+
+// A NamedHandler is a struct that contains a name and function callback.
+type NamedHandler struct {
+	Name string
+	Fn   func(*Request)
 }
 
 // copy creates a copy of the handler list.
 func (l *HandlerList) copy() HandlerList {
 	var n HandlerList
-	n.list = append([]func(*Request){}, l.list...)
+	n.list = append([]NamedHandler{}, l.list...)
 	return n
 }
 
 // Clear clears the handler list.
 func (l *HandlerList) Clear() {
-	l.list = []func(*Request){}
+	l.list = []NamedHandler{}
 }
 
 // Len returns the number of handlers in the list.
 func (l *HandlerList) Len() int {
 	return len(l.list)
 }
 
-// PushBack pushes handlers f to the back of the handler list.
-func (l *HandlerList) PushBack(f ...func(*Request)) {
-	l.list = append(l.list, f...)
+// PushBack pushes handler f to the back of the handler list.
+func (l *HandlerList) PushBack(f func(*Request)) {
+	l.list = append(l.list, NamedHandler{"__anonymous", f})
 }
 
-// PushFront pushes handlers f to the front of the handler list.
-func (l *HandlerList) PushFront(f ...func(*Request)) {
-	l.list = append(f, l.list...)
+// PushFront pushes handler f to the front of the handler list.
+func (l *HandlerList) PushFront(f func(*Request)) {
+	l.list = append([]NamedHandler{{"__anonymous", f}}, l.list...)
+}
+
+// PushBackNamed pushes named handler f to the back of the handler list.
+func (l *HandlerList) PushBackNamed(n NamedHandler) {
+	l.list = append(l.list, n)
+}
+
+// PushFrontNamed pushes named handler f to the front of the handler list.
+func (l *HandlerList) PushFrontNamed(n NamedHandler) {
+	l.list = append([]NamedHandler{n}, l.list...)
+}
+
+// Remove removes a NamedHandler n
+func (l *HandlerList) Remove(n NamedHandler) {
+	newlist := []NamedHandler{}
+	for _, m := range l.list {
+		if m.Name != n.Name {
+			newlist = append(newlist, m)
+		}
+	}
+	l.list = newlist
 }
 
 // Run executes all handlers in the list with a given request object.
 func (l *HandlerList) Run(r *Request) {
 	for _, f := range l.list {
-		f(r)
+		f.Fn(r)
 	}
 }

aws/request/handlers_test.go

@@ -32,3 +32,16 @@ func TestMultipleHandlers(t *testing.T) {
 		t.Error("Expected handler to execute")
 	}
 }
+
+func TestNamedHandlers(t *testing.T) {
+	l := request.HandlerList{}
+	named := request.NamedHandler{"Name", func(r *request.Request) {}}
+	named2 := request.NamedHandler{"NotName", func(r *request.Request) {}}
+	l.PushBackNamed(named)
+	l.PushBackNamed(named)
+	l.PushBackNamed(named2)
+	l.PushBack(func(r *request.Request) {})
+	assert.Equal(t, 4, l.Len())
+	l.Remove(named)
+	assert.Equal(t, 2, l.Len())
+}

aws/service/service.go

@@ -47,14 +47,14 @@ func (s *Service) Initialize() {
 
 	s.Retryer = DefaultRetryer{s}
 	s.DefaultMaxRetries = 3
-	s.Handlers.Validate.PushBack(corehandlers.ValidateEndpointHandler)
-	s.Handlers.Build.PushBack(corehandlers.UserAgentHandler)
-	s.Handlers.Sign.PushBack(corehandlers.BuildContentLength)
-	s.Handlers.Send.PushBack(corehandlers.SendHandler)
-	s.Handlers.AfterRetry.PushBack(corehandlers.AfterRetryHandler)
-	s.Handlers.ValidateResponse.PushBack(corehandlers.ValidateResponseHandler)
+	s.Handlers.Validate.PushBackNamed(corehandlers.ValidateEndpointHandler)
+	s.Handlers.Build.PushBackNamed(corehandlers.UserAgentHandler)
+	s.Handlers.Sign.PushBackNamed(corehandlers.BuildContentLengthHandler)
+	s.Handlers.Send.PushBackNamed(corehandlers.SendHandler)
+	s.Handlers.AfterRetry.PushBackNamed(corehandlers.AfterRetryHandler)
+	s.Handlers.ValidateResponse.PushBackNamed(corehandlers.ValidateResponseHandler)
 	if !aws.BoolValue(s.Config.DisableParamValidation) {
-		s.Handlers.Validate.PushBack(corehandlers.ValidateParameters)
+		s.Handlers.Validate.PushBackNamed(corehandlers.ValidateParametersHandler)
 	}
 	s.AddDebugHandlers()
 	s.buildEndpoint()