Addressing review comments

* Renamed the example
* Reworded comments
* Moved it to after worker pools
* Sleep for a second instead of random
* Mention the new sample in worker pools
This commit is contained in:
Eli Bendersky 2019-05-30 05:28:29 -07:00
parent 6ab81bdf71
commit 74ca2a7b0f
10 changed files with 48 additions and 46 deletions

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@ -23,7 +23,6 @@ Goroutines
Channels Channels
Channel Buffering Channel Buffering
Channel Synchronization Channel Synchronization
Waiting For Goroutines To Finish
Channel Directions Channel Directions
Select Select
Timeouts Timeouts
@ -33,6 +32,7 @@ Range over Channels
Timers Timers
Tickers Tickers
Worker Pools Worker Pools
WaitGroup
Rate Limiting Rate Limiting
Atomic Counters Atomic Counters
Mutexes Mutexes

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@ -1,27 +1,22 @@
// To wait for multiple goroutines to finish, we can // To wait for multiple goroutines to finish, we can
// use a sync.WaitGroup. // use a *wait group*.
package main package main
import ( import (
"fmt" "fmt"
"math/rand"
"sync" "sync"
"time" "time"
) )
// This is the function we'll run in every goroutine. // This is the function we'll run in every goroutine.
// wg is the WaitGroup it uses to notify that it's done.
// Note that a WaitGroup must be passed to functions by // Note that a WaitGroup must be passed to functions by
// pointer. // pointer.
func worker(id int, wg *sync.WaitGroup) { func worker(id int, wg *sync.WaitGroup) {
fmt.Printf("Worker %d starting\n", id) fmt.Printf("Worker %d starting\n", id)
// Sleep for a random duration between 500-700 ms // Sleep to simulate an expensive task.
// to simulate work. See the [random numbers](random-numbers) time.Sleep(time.Second)
// example for more details on *rand*.
msToSleep := time.Duration(500 + rand.Intn(200))
time.Sleep(msToSleep * time.Millisecond)
fmt.Printf("Worker %d done\n", id) fmt.Printf("Worker %d done\n", id)
// Notify the WaitGroup that we're done. // Notify the WaitGroup that we're done.

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@ -0,0 +1,2 @@
ffc6520e73ebfa2b8c470e3ef00fee55388234e0
8cD2V9CgI0J

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@ -1,4 +1,4 @@
$ go run waiting-for-goroutines-to-finish.go $ go run waitgroup.go
Worker 5 starting Worker 5 starting
Worker 3 starting Worker 3 starting
Worker 4 starting Worker 4 starting

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@ -1,2 +0,0 @@
f068072d11ed9469174c18f5b7a6a7d9d8d3dafb
koKzXfbq8kg

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@ -42,6 +42,9 @@ func main() {
close(jobs) close(jobs)
// Finally we collect all the results of the work. // Finally we collect all the results of the work.
// This also ensures that the worker goroutines have
// finished. An alternative way to wait for multiple
// goroutines is to use a [WaitGroup](waitgroup).
for a := 1; a <= 5; a++ { for a := 1; a <= 5; a++ {
<-results <-results
} }

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@ -1,2 +1,2 @@
1f9acf1e50be05cad73e6b085ed3294892c67d42 bfd2824b3840ff67fa9a0218c7be66647b4bf3d9
RTRcHA05vV IQestAFcxLh

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@ -171,7 +171,7 @@ started.</p>
<p class="next"> <p class="next">
Next example: <a href="waiting-for-goroutines-to-finish">Waiting For Goroutines To Finish</a>. Next example: <a href="channel-directions">Channel Directions</a>.
</p> </p>
<p class="footer"> <p class="footer">

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@ -85,8 +85,6 @@
<li><a href="channel-synchronization">Channel Synchronization</a></li> <li><a href="channel-synchronization">Channel Synchronization</a></li>
<li><a href="waiting-for-goroutines-to-finish">Waiting For Goroutines To Finish</a></li>
<li><a href="channel-directions">Channel Directions</a></li> <li><a href="channel-directions">Channel Directions</a></li>
<li><a href="select">Select</a></li> <li><a href="select">Select</a></li>
@ -105,6 +103,8 @@
<li><a href="worker-pools">Worker Pools</a></li> <li><a href="worker-pools">Worker Pools</a></li>
<li><a href="waitgroup">WaitGroup</a></li>
<li><a href="rate-limiting">Rate Limiting</a></li> <li><a href="rate-limiting">Rate Limiting</a></li>
<li><a href="atomic-counters">Atomic Counters</a></li> <li><a href="atomic-counters">Atomic Counters</a></li>

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@ -40,7 +40,7 @@ a <em>worker pool</em> using goroutines and channels.</p>
</td> </td>
<td class="code leading"> <td class="code leading">
<a href="http://play.golang.org/p/RTRcHA05vV"><img title="Run code" src="play.png" class="run" /></a> <a href="http://play.golang.org/p/IQestAFcxLh"><img title="Run code" src="play.png" class="run" /></a>
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span> <div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
</pre></div> </pre></div>
@ -147,7 +147,11 @@ channel to indicate that&rsquo;s all the work we have.</p>
<tr> <tr>
<td class="docs"> <td class="docs">
<p>Finally we collect all the results of the work.</p> <p>Finally we collect all the results of the work.
This also ensures that the worker goroutines have
finished. An alternative way to wait for multiple
goroutines that&rsquo;s useful in many scenarios is
to use a <a href="waitgroup">WaitGroup</a>.</p>
</td> </td>
<td class="code"> <td class="code">
@ -207,7 +211,7 @@ there are 3 workers operating concurrently.</p>
<p class="next"> <p class="next">
Next example: <a href="rate-limiting">Rate Limiting</a>. Next example: <a href="waitgroup">WaitGroup</a>.
</p> </p>
<p class="footer"> <p class="footer">