solution: simplify solution by just closing the tweets channel

1-producer-consumer/main.go

@@ -1,92 +1,30 @@
+//////////////////////////////////////////////////////////////////////
+//
+// Given is a producer-consumer szenario, where a producer reads in
+// tweets from a mockstream and a consumer is processing the
+// data. Your task is to change the code so that the producer as well
+// as the consumer can run concurrently
+//
+
 package main
 
 import (
-	"errors"
 	"fmt"
-	"strings"
 	"time"
 )
 
-// GetMockStream is a blackbox function which returns a mock stream for
-// demonstration purposes
-func GetMockStream() Stream {
-	return Stream{0, mockdata}
-}
-
-// Stream is a mock stream for demonstration purposes, not threadsafe
-type Stream struct {
-	pos    int
-	tweets []Tweet
-}
-
-// ErrEOF returns on End of File error
-var ErrEOF = errors.New("End of File")
-
-// Next returns the next Tweet in the stream, returns EOF error if
-// there are no more tweets
-func (s *Stream) Next() (*Tweet, error) {
-
-	// simulate delay
-	time.Sleep(320 * time.Millisecond)
-	if s.pos >= len(s.tweets) {
-		return &Tweet{}, ErrEOF
-	}
-
-	tweet := s.tweets[s.pos]
-	s.pos++
-
-	return &tweet, nil
-}
-
-// Tweet defines the simlified representation of a tweet
-type Tweet struct {
-	Username string
-	Text     string
-}
-
-// IsTalkingAboutGo is a mock process which pretend to be a sophisticated procedure to analyse whether tweet is talking about go or not
-func (t *Tweet) IsTalkingAboutGo() bool {
-	// simulate delay
-	time.Sleep(330 * time.Millisecond)
-
-	hasGolang := strings.Contains(strings.ToLower(t.Text), "golang")
-	hasGopher := strings.Contains(strings.ToLower(t.Text), "gopher")
-
-	return hasGolang || hasGopher
-}
-
-var mockdata = []Tweet{
-	{
-		"davecheney",
-		"#golang top tip: if your unit tests import any other package you wrote, including themselves, they're not unit tests.",
-	}, {
-		"beertocode",
-		"Backend developer, doing frontend featuring the eternal struggle of centering something. #coding",
-	}, {
-		"ironzeb",
-		"Re: Popularity of Golang in China: My thinking nowadays is that it had a lot to do with this book and author https://github.com/astaxie/build-web-application-with-golang",
-	}, {
-		"beertocode",
-		"Looking forward to the #gopher meetup in Hsinchu tonight with @ironzeb!",
-	}, {
-		"vampirewalk666",
-		"I just wrote a golang slack bot! It reports the state of github repository. #Slack #golang",
-	},
-}
-
-func producer(stream Stream, tweets chan *Tweet, quit chan bool) {
+func producer(stream Stream, tweets chan<- *Tweet) {
 	for {
 		tweet, err := stream.Next()
 		if err == ErrEOF {
-			quit <- true
 			close(tweets)
 			return
 		}
 		tweets <- tweet
 	}
 }
 
-func consumer(tweets chan *Tweet) {
+func consumer(tweets <-chan *Tweet) {
 	for t := range tweets {
 		if t.IsTalkingAboutGo() {
 			fmt.Println(t.Username, "\ttweets about golang")
@@ -100,23 +38,13 @@ func main() {
 	start := time.Now()
 	stream := GetMockStream()
 
-	// use two channels so we can gracefully stop listening for the tweets channel
 	tweets := make(chan *Tweet)
-	quit := make(chan bool, 1)
 
 	// Producer
-	go producer(stream, tweets, quit)
+	go producer(stream, tweets)
 
-	var done bool
-	for !done {
-		select {
-		case <-quit:
-			done = true
-		default:
-			// Consumer
-			consumer(tweets)
-		}
-	}
+	// Consumer
+	consumer(tweets)
 
 	fmt.Printf("Process took %s\n", time.Since(start))
 }

1-producer-consumer/mockstream.go

@@ -0,0 +1,80 @@
+//////////////////////////////////////////////////////////////////////
+//
+// DO NOT EDIT THIS PART
+// Your task is to edit `main.go`
+//
+
+package main
+
+import (
+	"errors"
+	"strings"
+	"time"
+)
+
+// GetMockStream is a blackbox function which returns a mock stream for
+// demonstration purposes
+func GetMockStream() Stream {
+	return Stream{0, mockdata}
+}
+
+// Stream is a mock stream for demonstration purposes, not threadsafe
+type Stream struct {
+	pos    int
+	tweets []Tweet
+}
+
+// ErrEOF returns on End of File error
+var ErrEOF = errors.New("End of File")
+
+// Next returns the next Tweet in the stream, returns EOF error if
+// there are no more tweets
+func (s *Stream) Next() (*Tweet, error) {
+
+	// simulate delay
+	time.Sleep(320 * time.Millisecond)
+	if s.pos >= len(s.tweets) {
+		return &Tweet{}, ErrEOF
+	}
+
+	tweet := s.tweets[s.pos]
+	s.pos++
+
+	return &tweet, nil
+}
+
+// Tweet defines the simlified representation of a tweet
+type Tweet struct {
+	Username string
+	Text     string
+}
+
+// IsTalkingAboutGo is a mock process which pretend to be a sophisticated procedure to analyse whether tweet is talking about go or not
+func (t *Tweet) IsTalkingAboutGo() bool {
+	// simulate delay
+	time.Sleep(330 * time.Millisecond)
+
+	hasGolang := strings.Contains(strings.ToLower(t.Text), "golang")
+	hasGopher := strings.Contains(strings.ToLower(t.Text), "gopher")
+
+	return hasGolang || hasGopher
+}
+
+var mockdata = []Tweet{
+	{
+		"davecheney",
+		"#golang top tip: if your unit tests import any other package you wrote, including themselves, they're not unit tests.",
+	}, {
+		"beertocode",
+		"Backend developer, doing frontend featuring the eternal struggle of centering something. #coding",
+	}, {
+		"ironzeb",
+		"Re: Popularity of Golang in China: My thinking nowadays is that it had a lot to do with this book and author https://github.com/astaxie/build-web-application-with-golang",
+	}, {
+		"beertocode",
+		"Looking forward to the #gopher meetup in Hsinchu tonight with @ironzeb!",
+	}, {
+		"vampirewalk666",
+		"I just wrote a golang slack bot! It reports the state of github repository. #Slack #golang",
+	},
+}