make frontend.TrackerFuncs an interface

backend/backend.go

@@ -20,7 +20,11 @@ package backend
 import (
 	"time"
 
+	"log"
+
+	"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.
@@ -35,6 +39,8 @@ type BackendConfig struct {
 	PostHooks        []GenericConfig `yaml:"posthooks"`
 }
 
+var _ frontend.TrackerFuncs = &Backend{}
+
 func New(config BackendConfig, peerStore PeerStore) (*Backend, error) {
 	// Build TrackerFuncs from the PreHooks and PostHooks
 	return &Backend{peerStore: peerStore}, nil
@@ -42,6 +48,36 @@ func New(config BackendConfig, peerStore PeerStore) (*Backend, error) {
 
 // Backend is a multi-protocol, customizable BitTorrent Tracker.
 type Backend struct {
-	TrackerFuncs frontend.TrackerFuncs
+	peerStore      PeerStore
-	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
+}
+
+// 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)
+}
+
+// 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())
+	}
+}
+
+// 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)
+}
+
+// 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())
+	}
 }

frontend/frontend.go

@@ -1,30 +1,25 @@
 package frontend
 
 import (
-	"github.com/jzelinskie/trakr/bittorrent"
 	"golang.org/x/net/context"
+
+	"github.com/jzelinskie/trakr/bittorrent"
 )
 
 // TrackerFuncs is the collection of callback functions provided by the Backend
 // to (1) generate a response from a parsed request, and (2) observe anything
 // after the response has been delivered to the client.
-type TrackerFuncs struct {
+type TrackerFuncs interface {
-	HandleAnnounce AnnounceHandler
+	// HandleAnnounce generates a response for an Announce.
-	HandleScrape   ScrapeHandler
+	HandleAnnounce(context.Context, *bittorrent.AnnounceRequest) (*bittorrent.AnnounceResponse, error)
-	AfterAnnounce  AnnounceCallback
+
-	AfterScrape    ScrapeCallback
+	// AfterAnnounce does something with the results of an Announce after it
+	// has been completed.
+	AfterAnnounce(context.Context, *bittorrent.AnnounceRequest, *bittorrent.AnnounceResponse)
+
+	// HandleScrape generates a response for a Scrape.
+	HandleScrape(context.Context, *bittorrent.ScrapeRequest) (*bittorrent.ScrapeResponse, error)
+
+	// AfterScrape does something with the results of a Scrape after it has been completed.
+	AfterScrape(context.Context, *bittorrent.ScrapeRequest, *bittorrent.ScrapeResponse)
 }
-
-// AnnounceHandler is a function that generates a response for an Announce.
-type AnnounceHandler func(context.Context, *bittorrent.AnnounceRequest) (*bittorrent.AnnounceResponse, error)
-
-// AnnounceCallback is a function that does something with the results of an
-// Announce after it has been completed.
-type AnnounceCallback func(*bittorrent.AnnounceRequest, *bittorrent.AnnounceResponse)
-
-// ScrapeHandler is a function that generates a response for a Scrape.
-type ScrapeHandler func(context.Context, *bittorrent.ScrapeRequest) (*bittorrent.ScrapeResponse, error)
-
-// ScrapeCallback is a function that does something with the results of a
-// Scrape after it has been completed.
-type ScrapeCallback func(*bittorrent.ScrapeRequest, *bittorrent.ScrapeResponse)

frontend/http/frontend.go

@@ -71,15 +71,15 @@ type Config struct {
 type Frontend struct {
 	grace *graceful.Server
 
-	frontend.TrackerFuncs
+	backend frontend.TrackerFuncs
 	Config
 }
 
 // NewFrontend allocates a new instance of a Frontend.
-func NewFrontend(funcs frontend.TrackerFuncs, cfg Config) *Frontend {
+func NewFrontend(backend frontend.TrackerFuncs, cfg Config) *Frontend {
 	return &Frontend{
-		TrackerFuncs: funcs,
+		backend: backend,
-		Config:       cfg,
+		Config:  cfg,
 	}
 }
 
@@ -150,7 +150,7 @@ func (t *Frontend) announceRoute(w http.ResponseWriter, r *http.Request, _ httpr
 		return
 	}
 
-	resp, err := t.HandleAnnounce(context.TODO(), req)
+	resp, err := t.backend.HandleAnnounce(context.TODO(), req)
 	if err != nil {
 		WriteError(w, err)
 		return
@@ -162,9 +162,7 @@ func (t *Frontend) announceRoute(w http.ResponseWriter, r *http.Request, _ httpr
 		return
 	}
 
-	if t.AfterAnnounce != nil {
+	go t.backend.AfterAnnounce(context.TODO(), req, resp)
-		go t.AfterAnnounce(req, resp)
-	}
 }
 
 // scrapeRoute parses and responds to a Scrape by using t.TrackerFuncs.
@@ -179,7 +177,7 @@ func (t *Frontend) scrapeRoute(w http.ResponseWriter, r *http.Request, _ httprou
 		return
 	}
 
-	resp, err := t.HandleScrape(context.TODO(), req)
+	resp, err := t.backend.HandleScrape(context.TODO(), req)
 	if err != nil {
 		WriteError(w, err)
 		return
@@ -191,7 +189,5 @@ func (t *Frontend) scrapeRoute(w http.ResponseWriter, r *http.Request, _ httprou
 		return
 	}
 
-	if t.AfterScrape != nil {
+	go t.backend.AfterScrape(context.TODO(), req, resp)
-		go t.AfterScrape(req, resp)
-	}
 }

frontend/udp/frontend.go

@@ -74,16 +74,16 @@ type Frontend struct {
 	closing chan struct{}
 	wg      sync.WaitGroup
 
-	frontend.TrackerFuncs
+	backend frontend.TrackerFuncs
 	Config
 }
 
 // NewFrontend allocates a new instance of a Frontend.
-func NewFrontend(funcs frontend.TrackerFuncs, cfg Config) *Frontend {
+func NewFrontend(backend frontend.TrackerFuncs, cfg Config) *Frontend {
 	return &Frontend{
-		closing:      make(chan struct{}),
+		closing: make(chan struct{}),
-		TrackerFuncs: funcs,
+		backend: backend,
-		Config:       cfg,
+		Config:  cfg,
 	}
 }
 
@@ -221,7 +221,7 @@ func (t *Frontend) handleRequest(r Request, w ResponseWriter) (response []byte,
 		}
 
 		var resp *bittorrent.AnnounceResponse
-		resp, err = t.HandleAnnounce(context.TODO(), req)
+		resp, err = t.backend.HandleAnnounce(context.TODO(), req)
 		if err != nil {
 			WriteError(w, txID, err)
 			return
@@ -229,9 +229,8 @@ func (t *Frontend) handleRequest(r Request, w ResponseWriter) (response []byte,
 
 		WriteAnnounce(w, txID, resp)
 
-		if t.AfterAnnounce != nil {
+		// TODO(mrd0ll4r): evaluate if it's worth spawning another goroutine.
-			go t.AfterAnnounce(req, resp)
+		go t.backend.AfterAnnounce(context.TODO(), req, resp)
-		}
 
 		return
 
@@ -246,7 +245,7 @@ func (t *Frontend) handleRequest(r Request, w ResponseWriter) (response []byte,
 		}
 
 		var resp *bittorrent.ScrapeResponse
-		resp, err = t.HandleScrape(context.TODO(), req)
+		resp, err = t.backend.HandleScrape(context.TODO(), req)
 		if err != nil {
 			WriteError(w, txID, err)
 			return
@@ -254,9 +253,7 @@ func (t *Frontend) handleRequest(r Request, w ResponseWriter) (response []byte,
 
 		WriteScrape(w, txID, resp)
 
-		if t.AfterScrape != nil {
+		go t.backend.AfterScrape(context.TODO(), req, resp)
-			go t.AfterScrape(req, resp)
-		}
 
 		return