add N of workers flag and truncate number of comments limit

azimut · Jul 27, 2022 · 2b2e7ad · 2b2e7ad
1 parent 7b8688a
commit 2b2e7ad
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Showing 2 changed files with 22 additions and 14 deletions.
diff --git a/cmd/hackerview/main.go b/cmd/hackerview/main.go
@@ -14,11 +14,11 @@ import (
 
 type options struct {
 	timeout   time.Duration
-	userAgent string
 	useColors bool
 	usePretty bool
 	width     int
 	limit     int
+	workers   uint
 }
 
 var opt options
@@ -30,6 +30,7 @@ func init() {
 	flag.BoolVar(&opt.usePretty, "P", true, "use pretty formatting")
 	flag.IntVar(&opt.width, "w", 80, "fixed with")
 	flag.IntVar(&opt.limit, "l", 0, "limits the ammount of comments to fetch")
+	flag.UintVar(&opt.workers, "W", 3, "number of workers to fetch comments")
 }
 
 func usage() {
@@ -45,7 +46,7 @@ func run(args []string, stdout io.Writer) error {
 		return errors.New("missing URL argument")
 	}
 	url = flag.Args()[0]
-	op, comments, err := hackernews.Fetch(url, opt.timeout, opt.limit)
+	op, comments, err := hackernews.Fetch(url, opt.timeout, opt.limit, opt.workers)
 	if err != nil {
 		return errors.New("could not fetch url")
 	}

diff --git a/internal/hackernews/fetch.go b/internal/hackernews/fetch.go
@@ -8,8 +8,6 @@ import (
 	"github.com/caser/gophernews"
 )
 
-const NUM_OF_WORKERS = 3
-
 func unix2time(t int) time.Time {
 	return time.Unix(int64(t), 0)
 }
@@ -26,7 +24,12 @@ func newOp(story *gophernews.Story, selfUrl string) Op {
 	}
 }
 
-func Fetch(rawUrl string, timeout time.Duration, limit int) (doc *Op, c *[]Comment, err error) {
+func Fetch(
+	rawUrl string,
+	timeout time.Duration,
+	limit int,
+	workers uint,
+) (doc *Op, c *[]Comment, err error) {
 	url, storyId, err := effectiveUrl(rawUrl)
 	if err != nil {
 		return nil, nil, err
@@ -38,13 +41,21 @@ func Fetch(rawUrl string, timeout time.Duration, limit int) (doc *Op, c *[]Comme
 	}
 	op := newOp(story, url)
 	ids := story.Kids
+	limit = min(len(ids), limit)
 	if limit > 0 {
 		ids = ids[:limit]
 	}
-	comments := fetchComments(ids) // TODO: error
+	comments := fetchComments(ids, workers) // TODO: error
 	return &op, &comments, nil
 }
 
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
 func fetchStory(client *gophernews.Client, id int) (*gophernews.Story, error) {
 	story, err := client.GetStory(id)
 	if err != nil {
@@ -56,14 +67,16 @@ func fetchStory(client *gophernews.Client, id int) (*gophernews.Story, error) {
 	return &story, nil
 }
 
-func fetchComments(comments []int) []Comment {
+func fetchComments(comments []int, workers uint) []Comment {
 	idsChan := make(chan int, 5)
 	commentsCh := make(chan result, 5)
 	var wg sync.WaitGroup
 	wg.Add(len(comments))
 	go sendWork(comments, idsChan)
 	go closeAfterWait(&wg, commentsCh)
-	spawnWorkers(&wg, idsChan, commentsCh)
+	for i := 0; i < int(workers); i++ {
+		go worker(&wg, idsChan, commentsCh)
+	}
 	return collector(&wg, idsChan, commentsCh)
 }
 
@@ -79,12 +92,6 @@ func sendWork(ids []int, input chan<- int) {
 	close(input)
 }
 
-func spawnWorkers(wg *sync.WaitGroup, in <-chan int, out chan<- result) {
-	for i := 0; i < NUM_OF_WORKERS; i++ {
-		go worker(wg, in, out)
-	}
-}
-
 type result struct {
 	comment gophernews.Comment
 	err     error