remove register pattern for hooks

backend/backend.go

@@ -14,70 +14,109 @@
 
 // Package trakr implements a BitTorrent Tracker that supports multiple
 // protocols and configurable Hooks that execute before and after a Response
-// has been delievered to a BitTorrent client.
+// has been delivered to a BitTorrent client.
 package backend
 
 import (
+	"log"
 	"time"
 
-	"log"
+	"golang.org/x/net/context"
 
 	"github.com/jzelinskie/trakr/bittorrent"
 	"github.com/jzelinskie/trakr/frontend"
-	"golang.org/x/net/context"
 )
 
-// GenericConfig is a block of configuration who's structure is unknown.
-type GenericConfig struct {
-	name   string      `yaml:"name"`
-	config interface{} `yaml:"config"`
-}
-
 type BackendConfig struct {
-	AnnounceInterval time.Duration   `yaml:"announce_interval"`
-	PreHooks         []GenericConfig `yaml:"prehooks"`
-	PostHooks        []GenericConfig `yaml:"posthooks"`
+	AnnounceInterval time.Duration `yaml:"announce_interval"`
 }
 
 var _ frontend.TrackerFuncs = &Backend{}
 
-func New(config BackendConfig, peerStore PeerStore) (*Backend, error) {
-	// Build TrackerFuncs from the PreHooks and PostHooks
-	return &Backend{peerStore: peerStore}, nil
+func New(config BackendConfig, peerStore PeerStore, announcePreHooks, announcePostHooks, scrapePreHooks, scrapePostHooks []Hook) (*Backend, error) {
+	toReturn := &Backend{
+		announceInterval:  config.AnnounceInterval,
+		peerStore:         peerStore,
+		announcePreHooks:  announcePreHooks,
+		announcePostHooks: announcePostHooks,
+		scrapePreHooks:    scrapePreHooks,
+		scrapePostHooks:   scrapePostHooks,
+	}
+
+	if len(toReturn.announcePreHooks) == 0 {
+		toReturn.announcePreHooks = []Hook{nopHook{}}
+	}
+
+	if len(toReturn.announcePostHooks) == 0 {
+		toReturn.announcePostHooks = []Hook{nopHook{}}
+	}
+
+	if len(toReturn.scrapePreHooks) == 0 {
+		toReturn.scrapePreHooks = []Hook{nopHook{}}
+	}
+
+	if len(toReturn.scrapePostHooks) == 0 {
+		toReturn.scrapePostHooks = []Hook{nopHook{}}
+	}
+
+	return toReturn, nil
 }
 
-// Backend is a multi-protocol, customizable BitTorrent Tracker.
+// Backend is a protocol-agnostic backend of a BitTorrent tracker.
 type Backend struct {
-	peerStore      PeerStore
-	handleAnnounce func(context.Context, *bittorrent.AnnounceRequest) (*bittorrent.AnnounceResponse, error)
-	afterAnnounce  func(context.Context, *bittorrent.AnnounceRequest, *bittorrent.AnnounceResponse) error
-	handleScrape   func(context.Context, *bittorrent.ScrapeRequest) (*bittorrent.ScrapeResponse, error)
-	afterScrape    func(context.Context, *bittorrent.ScrapeRequest, *bittorrent.ScrapeResponse) error
+	announceInterval  time.Duration
+	peerStore         PeerStore
+	announcePreHooks  []Hook
+	announcePostHooks []Hook
+	scrapePreHooks    []Hook
+	scrapePostHooks   []Hook
 }
 
 // HandleAnnounce generates a response for an Announce.
 func (b *Backend) HandleAnnounce(ctx context.Context, req *bittorrent.AnnounceRequest) (*bittorrent.AnnounceResponse, error) {
-	return b.handleAnnounce(ctx, req)
+	resp := &bittorrent.AnnounceResponse{
+		Interval: b.announceInterval,
+	}
+	for _, h := range b.announcePreHooks {
+		if err := h.HandleAnnounce(ctx, req, resp); err != nil {
+			return nil, err
+		}
+	}
+
+	return resp, nil
 }
 
 // AfterAnnounce does something with the results of an Announce after it
 // has been completed.
 func (b *Backend) AfterAnnounce(ctx context.Context, req *bittorrent.AnnounceRequest, resp *bittorrent.AnnounceResponse) {
-	err := b.afterAnnounce(ctx, req, resp)
-	if err != nil {
-		log.Println("trakr: post-announce hooks failed:", err.Error())
+	for _, h := range b.announcePostHooks {
+		if err := h.HandleAnnounce(ctx, req, resp); err != nil {
+			log.Println("trakr: post-announce hooks failed:", err.Error())
+			return
+		}
 	}
 }
 
 // HandleScrape generates a response for a Scrape.
 func (b *Backend) HandleScrape(ctx context.Context, req *bittorrent.ScrapeRequest) (*bittorrent.ScrapeResponse, error) {
-	return b.handleScrape(ctx, req)
+	resp := &bittorrent.ScrapeResponse{
+		Files: make(map[bittorrent.InfoHash]bittorrent.Scrape),
+	}
+	for _, h := range b.scrapePreHooks {
+		if err := h.HandleScrape(ctx, req, resp); err != nil {
+			return nil, err
+		}
+	}
+
+	return resp, nil
 }
 
 // AfterScrape does something with the results of a Scrape after it has been completed.
 func (b *Backend) AfterScrape(ctx context.Context, req *bittorrent.ScrapeRequest, resp *bittorrent.ScrapeResponse) {
-	err := b.afterScrape(ctx, req, resp)
-	if err != nil {
-		log.Println("trakr: post-scrape hooks failed:", err.Error())
+	for _, h := range b.scrapePostHooks {
+		if err := h.HandleScrape(ctx, req, resp); err != nil {
+			log.Println("trakr: post-scrape hooks failed:", err.Error())
+			return
+		}
 	}
 }

backend/hooks.go

@@ -15,8 +15,6 @@
 package backend
 
 import (
-	"fmt"
-
 	"golang.org/x/net/context"
 
 	"github.com/jzelinskie/trakr/bittorrent"
@@ -29,55 +27,12 @@ type Hook interface {
 	HandleScrape(context.Context, *bittorrent.ScrapeRequest, *bittorrent.ScrapeResponse) error
 }
 
-// HookConstructor is a function used to create a new instance of a Hook.
-type HookConstructor func(interface{}) (Hook, error)
+type nopHook struct{}
 
-var preHooks = make(map[string]HookConstructor)
-
-// RegisterPreHook makes a HookConstructor available by the provided name.
-//
-// If this function is called twice with the same name or if the
-// HookConstructor is nil, it panics.
-func RegisterPreHook(name string, con HookConstructor) {
-	if con == nil {
-		panic("trakr: could not register nil HookConstructor")
-	}
-	if _, dup := preHooks[name]; dup {
-		panic("trakr: could not register duplicate HookConstructor: " + name)
-	}
-	preHooks[name] = con
+func (nopHook) HandleAnnounce(context.Context, *bittorrent.AnnounceRequest, *bittorrent.AnnounceResponse) error {
+	return nil
 }
 
-// NewPreHook creates an instance of the given PreHook by name.
-func NewPreHook(name string, config interface{}) (Hook, error) {
-	con, ok := preHooks[name]
-	if !ok {
-		return nil, fmt.Errorf("trakr: unknown PreHook %q (forgotten import?)", name)
-	}
-	return con(config)
-}
-
-var postHooks = make(map[string]HookConstructor)
-
-// RegisterPostHook makes a HookConstructor available by the provided name.
-//
-// If this function is called twice with the same name or if the
-// HookConstructor is nil, it panics.
-func RegisterPostHook(name string, con HookConstructor) {
-	if con == nil {
-		panic("trakr: could not register nil HookConstructor")
-	}
-	if _, dup := postHooks[name]; dup {
-		panic("trakr: could not register duplicate HookConstructor: " + name)
-	}
-	preHooks[name] = con
-}
-
-// NewPostHook creates an instance of the given PostHook by name.
-func NewPostHook(name string, config interface{}) (Hook, error) {
-	con, ok := preHooks[name]
-	if !ok {
-		return nil, fmt.Errorf("trakr: unknown PostHook %q (forgotten import?)", name)
-	}
-	return con(config)
+func (nopHook) HandleScrape(context.Context, *bittorrent.ScrapeRequest, *bittorrent.ScrapeResponse) error {
+	return nil
 }

cmd/trakr/main.go

@@ -15,7 +15,6 @@ import (
 	"gopkg.in/yaml.v2"
 
 	"github.com/jzelinskie/trakr/backend"
-
 	httpfrontend "github.com/jzelinskie/trakr/frontend/http"
 	udpfrontend "github.com/jzelinskie/trakr/frontend/udp"
 )
@@ -95,7 +94,8 @@ func main() {
 				}()
 
 				// TODO create PeerStore
-				trackerBackend, err := backend.New(configFile.Config.BackendConfig, nil)
+				// TODO create Hooks
+				trackerBackend, err := backend.New(configFile.Config.BackendConfig, nil, nil, nil, nil, nil)
 				if err != nil {
 					return err
 				}
@@ -108,7 +108,7 @@ func main() {
 
 				if configFile.Config.HTTPConfig.Addr != "" {
 					// TODO get the real TrackerFuncs
-					hFrontend = httpfrontend.NewFrontend(trackerBackend.TrackerFuncs, configFile.Config.HTTPConfig)
+					hFrontend = httpfrontend.NewFrontend(trackerBackend, configFile.Config.HTTPConfig)
 
 					go func() {
 						log.Println("started serving HTTP on", configFile.Config.HTTPConfig.Addr)
@@ -120,7 +120,7 @@ func main() {
 
 				if configFile.Config.UDPConfig.Addr != "" {
 					// TODO get the real TrackerFuncs
-					uFrontend = udpfrontend.NewFrontend(trackerBackend.TrackerFuncs, configFile.Config.UDPConfig)
+					uFrontend = udpfrontend.NewFrontend(trackerBackend, configFile.Config.UDPConfig)
 
 					go func() {
 						log.Println("started serving UDP on", configFile.Config.UDPConfig.Addr)