Restructure Daemon with updater and downloader threads. Implement download

queue.

.gitignore

@@ -1,3 +1,4 @@
+rssd
 rssd.conf
 output.conf
 *.mp3

main.go

@@ -1,12 +1,18 @@
 package main
 
 import (
+	"fmt"
 	"log"
+	"net/url"
 	"os"
+	"path"
+	"sort"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/BurntSushi/toml"
+	"github.com/cavaliercoder/grab"
 	"github.com/mmcdole/gofeed"
 )
 
@@ -17,6 +23,8 @@ type Config struct {
 type Item struct {
 	Title, Description, Url, Filename string
 	Length int
+	Published time.Time
+	Podcast *Podcast
 }
 
 type Podcast struct {
@@ -64,7 +72,6 @@ func (p *pcList) Add(x *Podcast) {
 func (p *Podcast) Merge(x *Podcast) {
 	for _,item := range x.Items {
 		if !p.Has(item) {
-			log.Print("        Appending '",item.Title,"'")
 			p.Items = append(p.Items,item)
 		}
 	}
@@ -117,11 +124,11 @@ func daysAgo(x int) Selector {
 	return newerThan(time.Date(d.Year(),d.Month(),d.Day()-x,0,0,0,0,time.Local))
 }
 
-func toPodcast(sel Selector, url string, feed *gofeed.Feed) (ret *Podcast) {
+func toPodcast(sel Selector, u string, feed *gofeed.Feed) (ret *Podcast) {
 	ret = &Podcast{
 		Title: feed.Title,
 		Description: feed.Description,
-		Url: url,
+		Url: u,
 		Items: []Item{},
 	}
 	for _, i := range feed.Items {
@@ -129,10 +136,17 @@ func toPodcast(sel Selector, url string, feed *gofeed.Feed) (ret *Podcast) {
 			it := Item{
 				Title: i.Title,
 				Description: i.Description,
+				Filename: path.Join(ret.Title, i.Title),
+				Published: *i.PublishedParsed,
 			}
 			for _, n := range i.Enclosures {
 				if n.Type == "audio/mpeg" {
+					u,err := url.Parse(n.URL)
+					if err != nil {
 						it.Url = n.URL
+					} else {
+						it.Url = fmt.Sprintf("%s://%s%s",u.Scheme,u.Host,u.Path)
+					}
 					if l, err := strconv.Atoi(n.Length); err == nil {
 						it.Length = l
 					}
@@ -144,14 +158,225 @@ func toPodcast(sel Selector, url string, feed *gofeed.Feed) (ret *Podcast) {
 	return
 }
 
-func readFeed(url string,sel Selector) *Podcast {
+func readFeed(u string,sel Selector) *Podcast {
 	fp := gofeed.NewParser()
-	feed, err := fp.ParseURL(url)
+	feed, err := fp.ParseURL(u)
 	if err != nil {
 		log.Print(err)
 		return nil
 	}
-	return toPodcast(sel,url,feed)
+	return toPodcast(sel,u,feed)
+}
+
+type dlItem struct {
+	Item *Item
+	downloading bool
+}
+
+type ByDate []*dlItem
+func (a ByDate) Len() int		{ return len(a) }
+func (a ByDate) Swap(i, j int)		{ a[i], a[j] = a[j], a[i] }
+func (a ByDate) Less(i, j int) bool	{ return a[j].Item.Published.After(a[i].Item.Published) }
+
+type dlQueue struct {
+	items []*dlItem
+	reqch chan *grab.Request
+	respch chan *grab.Response
+	sync.Mutex
+	wg sync.WaitGroup
+}
+
+func (q *dlQueue) Sort() {
+	sort.Sort(ByDate(q.items))
+}
+
+func (q *dlQueue) Find(x *Item) (int, bool) {
+	for i,y := range q.items {
+		if y.Item.Title == x.Title {
+			return i, true
+		}
+	}
+	return 0, false
+}
+
+func (q *dlQueue) Waiting() *dlQueue {
+	ret := &dlQueue{
+		items: make([]*dlItem,0),
+		reqch: q.reqch,
+		respch: q.respch,
+		Mutex: q.Mutex,
+		wg: q.wg,
+	}
+	for _,i := range q.items {
+		if i.downloading == false {
+			ret.items = append(ret.items,i)
+		}
+	}
+	return ret
+}
+
+func (q *dlQueue) Add(i *Item) {
+	if _, ok := q.Find(i); ok == true {
+		return
+	}
+	di := &dlItem{Item: &Item{} }
+	*di.Item = *i
+	q.items = append(q.items,di)
+}
+
+type Daemon struct {
+	conf Config
+	g *grab.Client
+	pl *pcList
+	queue *dlQueue
+	sync.Mutex
+}
+
+func NewDaemon(conf Config, pl *pcList) *Daemon {
+	return &Daemon{
+		conf: conf,
+		g: grab.NewClient(),
+		pl: pl,
+		queue: &dlQueue{},
+	}
+}
+
+func (d *Daemon) Update(urls []string) {
+	sel := daysAgo(60)
+	for _,url := range urls {
+		log.Print("  -> ",url)
+		f := readFeed(url,sel) // do not lock around IO
+		d.Lock()
+		d.pl.Add(f)
+		d.Unlock()
+	}
+}
+
+func (d *Daemon) Monitor() {
+	status := func(resp *grab.Response) {
+		log.Printf("  %s: %v bytes (%.2f%%)\n",
+			resp.Filename,
+			resp.BytesComplete(),
+			100*resp.Progress())
+	}
+	mon := func(resp *grab.Response) {
+		t := time.NewTicker(1 * time.Second)
+		defer t.Stop()
+		Loop:
+		for {
+			select {
+			case <-t.C:
+				status(resp)
+			case <-resp.Done:
+				status(resp)
+				break Loop
+			}
+		}
+		if err := resp.Err(); err != nil {
+			log.Printf("Download failed for %s (%s)\n",resp.Filename,err)
+		}
+	}
+	for {
+		mon(<-d.queue.respch)
+	}
+}
+
+func (d *Daemon) Downloader(workers int) {
+	log.Print("Downloader(): starting")
+	d.queue.reqch = make(chan *grab.Request)
+	d.queue.respch = make(chan *grab.Response)
+	log.Print("Downloader(): spawning workers")
+	for i := 0; i < workers; i++ {
+		d.queue.wg.Add(1)
+		go func() {
+			d.g.DoChannel(d.queue.reqch,d.queue.respch)
+			d.queue.wg.Done()
+		}()
+	}
+	log.Print("Downloader(): starting monitor")
+	go d.Monitor()
+
+	if d.queue.items == nil {
+		d.queue.Lock()
+		d.queue.items = make([]*dlItem,0)
+		d.queue.Unlock()
+	}
+	upd := make(chan struct{})
+	go func() {
+		for {
+			// lock Podcast list and update download queue
+			log.Print("Downloader(): Updating podcast list")
+			d.queue.Lock()
+			for _,p := range d.pl.Podcasts {
+				for _,i := range p.Items {
+					d.queue.Add(&i)
+				}
+			}
+			log.Print("Done updating podcast list")
+			d.queue.Unlock()
+			upd<- struct{}{}
+			time.Sleep(30 * time.Second)
+		}
+	}()
+	t := time.NewTicker(30 * time.Second)
+	defer t.Stop()
+	LOOP:
+	for {
+		// launch requests for files we are not yet downloading
+		d.queue.Lock()
+		waiting := d.queue.Waiting()
+		d.queue.Unlock()
+		log.Print("Download queue length: ",len(waiting.items))
+		for _,i := range waiting.items {
+			if !i.downloading {
+				dst := path.Join("downloads",path.Base(i.Item.Url))
+				req,err := grab.NewRequest(dst,i.Item.Url)
+				if err != nil {
+					log.Print("Request error: ",err)
+					continue
+				}
+				i.downloading = true
+				t := time.Now()
+				d.queue.reqch <- req
+				if time.Now().After(t.Add(5 * time.Second)) {
+					continue LOOP // refresh list
+				}
+			}
+		}
+		log.Print("Downloader(): Done launching downloads")
+		log.Print("Downloader(): sleeping")
+		select {
+		case <-t.C:
+			continue LOOP
+		case <-upd:
+			continue LOOP
+		}
+	}
+}
+
+func (d *Daemon) Updater() {
+	for {
+		time.Sleep(1 * time.Second)
+		d.Lock()
+		d.Update(d.conf.Urls)
+		of,err := os.Create("output.conf")
+		if err != nil {
+			log.Print("Cannot open output file")
+		} else {
+			enc := toml.NewEncoder(of)
+			log.Print("writing output")
+			enc.Encode(d.pl)
+			of.Close()
+			log.Print("done")
+		}
+		d.Unlock()
+		time.Sleep(30 * time.Minute)
+	}
+}
+
+func (d *Daemon) Start() {
+	go d.Downloader(3) // use 3 download queues
+	go d.Updater()
 }
 
 func main() {
@@ -161,20 +386,9 @@ func main() {
 	if _, err := toml.DecodeFile("rssd.conf", &conf); err != nil {
 		log.Fatal("Error reading config file:",err)
 	}
-	pl := newpcList("output.conf")
 
-	sel := daysAgo(60)
+	pl := newpcList("output.conf")
-	for _,url := range conf.Urls {
+	d := NewDaemon(conf,pl)
-		log.Print("  -> ",url)
+	d.Start()
-		pl.Add(readFeed(url,sel))
+	select { }
-	}
-	of,err := os.Create("output.conf")
-	if err != nil {
-		log.Fatal("Cannot open output file")
-	}
-	enc := toml.NewEncoder(of)
-	log.Print("writing output")
-	enc.Encode(pl)
-	of.Close()
-	log.Print("done")
 }