implement a dynamic router handler for #2167

Author: kataras

_examples/routing/route-state/main.go

@@ -41,5 +41,5 @@ func main() {
 		ctx.Exec("GET", "/invisible/iris")
 	})
 
-	app.Listen(":8080")
+	app.Listen(":8080", iris.WithDynamicHandler)
 }

configuration.go

@@ -308,6 +308,14 @@ var WithLowercaseRouting = func(app *Application) {
 	app.config.ForceLowercaseRouting = true
 }
 
+// WithDynamicHandler enables for dynamic routing by
+// setting the `EnableDynamicHandler` to true.
+//
+// See `Configuration`.
+var WithDynamicHandler = func(app *Application) {
+	app.config.EnableDynamicHandler = true
+}
+
 // WithOptimizations can force the application to optimize for the best performance where is possible.
 //
 // See `Configuration`.
@@ -737,6 +745,14 @@ type Configuration struct {
 	//
 	// Defaults to false.
 	ForceLowercaseRouting bool `ini:"force_lowercase_routing" json:"forceLowercaseRouting,omitempty" yaml:"ForceLowercaseRouting" toml:"ForceLowercaseRouting"`
+	// EnableOptimizations enables dynamic request handler.
+	// It gives the router the feature to add routes while in serve-time,
+	// when `RefreshRouter` is called.
+	// If this setting is set to true, the request handler will use a mutex for data(trie routing) protection,
+	// hence the performance cost.
+	//
+	// Defaults to false.
+	EnableDynamicHandler bool `ini:"enable_dynamic_handler" json:"enableDynamicHandler,omitempty" yaml:"EnableDynamicHandler" toml:"EnableDynamicHandler"`
 	// FireMethodNotAllowed if it's true router checks for StatusMethodNotAllowed(405) and
 	//  fires the 405 error instead of 404
 	// Defaults to false.
@@ -1008,6 +1024,11 @@ func (c *Configuration) GetForceLowercaseRouting() bool {
 	return c.ForceLowercaseRouting
 }
 
+// GetEnableDynamicHandler returns the EnableDynamicHandler field.
+func (c *Configuration) GetEnableDynamicHandler() bool {
+	return c.EnableDynamicHandler
+}
+
 // GetFireMethodNotAllowed returns the FireMethodNotAllowed field.
 func (c *Configuration) GetFireMethodNotAllowed() bool {
 	return c.FireMethodNotAllowed

context/configuration.go

@@ -34,6 +34,8 @@ type ConfigurationReadOnly interface {
 	GetEnablePathEscape() bool
 	// GetForceLowercaseRouting returns the ForceLowercaseRouting field.
 	GetForceLowercaseRouting() bool
+	// GetEnableOptimizations returns the EnableDynamicHandler field.
+	GetEnableDynamicHandler() bool
 	// GetFireMethodNotAllowed returns the FireMethodNotAllowed field.
 	GetFireMethodNotAllowed() bool
 	// GetDisableAutoFireStatusCode returns the DisableAutoFireStatusCode field.

core/router/handler.go

@@ -1,10 +1,13 @@
 package router
 
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"sort"
 	"strings"
+	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/kataras/iris/v12/context"
@@ -39,8 +42,18 @@ type (
 		// on the given context's response status code.
 		FireErrorCode(ctx *context.Context)
 	}
+
+	// RouteAdder is an optional interface that can be implemented by a `RequestHandler`.
+	RouteAdder interface {
+		// AddRoute should add a route to the request handler directly.
+		AddRoute(*Route) error
+	}
 )
 
+// ErrNotRouteAdder throws on `AddRouteUnsafe` when a registered `RequestHandler`
+// does not implements the optional `AddRoute(*Route) error` method.
+var ErrNotRouteAdder = errors.New("request handler does not implement AddRoute method")
+
 type routerHandler struct {
 	// Config.
 	disablePathCorrection            bool
@@ -59,8 +72,103 @@ type routerHandler struct {
 	errorDefaultHandlers context.Handlers // the main handler(s) for default error code handlers, when not registered directly by the end-developer.
 }
 
-var _ RequestHandler = (*routerHandler)(nil)
-var _ HTTPErrorHandler = (*routerHandler)(nil)
+var (
+	_ RequestHandler   = (*routerHandler)(nil)
+	_ HTTPErrorHandler = (*routerHandler)(nil)
+)
+
+type routerHandlerDynamic struct {
+	RequestHandler
+	rw sync.RWMutex
+
+	locked uint32
+}
+
+// RouteExists reports whether a particular route exists.
+func (h *routerHandlerDynamic) RouteExists(ctx *context.Context, method, path string) (exists bool) {
+	h.lock(false, func() error {
+		exists = h.RequestHandler.RouteExists(ctx, method, path)
+		return nil
+	})
+
+	return
+}
+
+func (h *routerHandlerDynamic) AddRoute(r *Route) error {
+	if v, ok := h.RequestHandler.(RouteAdder); ok {
+		return h.lock(true, func() error {
+			return v.AddRoute(r)
+		})
+	}
+
+	return ErrNotRouteAdder
+}
+
+func (h *routerHandlerDynamic) lock(writeAccess bool, fn func() error) error {
+	if atomic.CompareAndSwapUint32(&h.locked, 0, 1) {
+		if writeAccess {
+			h.rw.Lock()
+		} else {
+			h.rw.RLock()
+		}
+
+		err := fn()
+
+		// check agan because fn may called the unlock method.
+		if atomic.CompareAndSwapUint32(&h.locked, 1, 0) {
+			if writeAccess {
+				h.rw.Unlock()
+			} else {
+				h.rw.RUnlock()
+			}
+		}
+
+		return err
+	}
+
+	return fn()
+}
+
+func (h *routerHandlerDynamic) Build(provider RoutesProvider) error {
+	// Build can be called inside HandleRequest if the route handler
+	// calls the RefreshRouter method, and it will stuck on the rw.Lock() call,
+	// so use a custom version of it.
+	// h.rw.Lock()
+	// defer h.rw.Unlock()
+
+	return h.lock(true, func() error {
+		return h.RequestHandler.Build(provider)
+	})
+}
+
+func (h *routerHandlerDynamic) HandleRequest(ctx *context.Context) {
+	h.lock(false, func() error {
+		h.RequestHandler.HandleRequest(ctx)
+		return nil
+	})
+}
+
+func (h *routerHandlerDynamic) FireErrorCode(ctx *context.Context) {
+	h.lock(false, func() error {
+		h.RequestHandler.FireErrorCode(ctx)
+		return nil
+	})
+}
+
+// NewDynamicHandler returns a new router handler which is responsible handle each request
+// with routes that can be added in serve-time.
+// It's a wrapper of the `NewDefaultHandler`.
+// It's being used when the `ConfigurationReadOnly.GetEnableDynamicHandler` is true.
+func NewDynamicHandler(config context.ConfigurationReadOnly, logger *golog.Logger) RequestHandler /* #2167 */ {
+	handler := NewDefaultHandler(config, logger)
+	return wrapDynamicHandler(handler)
+}
+
+func wrapDynamicHandler(handler RequestHandler) RequestHandler {
+	return &routerHandlerDynamic{
+		RequestHandler: handler,
+	}
+}
 
 // NewDefaultHandler returns the handler which is responsible
 // to map the request with a route (aka mux implementation).
@@ -71,6 +179,7 @@ func NewDefaultHandler(config context.ConfigurationReadOnly, logger *golog.Logge
 		fireMethodNotAllowed             bool
 		enablePathIntelligence           bool
 		forceLowercaseRouting            bool
+		dynamicHandlerEnabled            bool
 	)
 
 	if config != nil { // #2147
@@ -79,16 +188,23 @@ func NewDefaultHandler(config context.ConfigurationReadOnly, logger *golog.Logge
 		fireMethodNotAllowed = config.GetFireMethodNotAllowed()
 		enablePathIntelligence = config.GetEnablePathIntelligence()
 		forceLowercaseRouting = config.GetForceLowercaseRouting()
+		dynamicHandlerEnabled = config.GetEnableDynamicHandler()
 	}
 
-	return &routerHandler{
+	handler := &routerHandler{
 		disablePathCorrection:            disablePathCorrection,
 		disablePathCorrectionRedirection: disablePathCorrectionRedirection,
 		fireMethodNotAllowed:             fireMethodNotAllowed,
 		enablePathIntelligence:           enablePathIntelligence,
 		forceLowercaseRouting:            forceLowercaseRouting,
 		logger:                           logger,
 	}
+
+	if dynamicHandlerEnabled {
+		return wrapDynamicHandler(handler)
+	}
+
+	return handler
 }
 
 func (h *routerHandler) getTree(statusCode int, method, subdomain string) *trie {

core/router/route_register_rule_test.go

@@ -12,6 +12,8 @@ import (
 
 func TestRegisterRule(t *testing.T) {
 	app := iris.New()
+	app.Configure(iris.WithDynamicHandler)
+
 	// collect the error on RouteError rule.
 	buf := new(bytes.Buffer)
 	app.Logger().SetTimeFormat("").DisableNewLine().SetOutput(buf)

core/router/router.go

@@ -49,23 +49,21 @@ func NewRouter() *Router {
 
 // RefreshRouter re-builds the router. Should be called when a route's state
 // changed (i.e Method changed at serve-time).
+//
+// Note that in order to use RefreshRouter while in serve-time,
+// you have to set the `EnableDynamicHandler` Iris Application setting to true,
+// e.g. `app.Listen(":8080", iris.WithEnableDynamicHandler)`
 func (router *Router) RefreshRouter() error {
 	return router.BuildRouter(router.cPool, router.requestHandler, router.routesProvider, true)
 }
 
-// ErrNotRouteAdder throws on `AddRouteUnsafe` when a registered `RequestHandler`
-// does not implements the optional `AddRoute(*Route) error` method.
-var ErrNotRouteAdder = errors.New("request handler does not implement AddRoute method")
-
 // AddRouteUnsafe adds a route directly to the router's request handler.
 // Works before or after Build state.
 // Mainly used for internal cases like `iris.WithSitemap`.
 // Do NOT use it on serve-time.
 func (router *Router) AddRouteUnsafe(routes ...*Route) error {
 	if h := router.requestHandler; h != nil {
-		if v, ok := h.(interface {
-			AddRoute(*Route) error
-		}); ok {
+		if v, ok := h.(RouteAdder); ok {
 			for _, r := range routes {
 				return v.AddRoute(r)
 			}