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Clarify the signals example slightly

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Based on feedback in #402
This commit is contained in:
Eli Bendersky 2021-12-02 06:31:37 -08:00
parent dad9113134
commit 80fb5ebddf
6 changed files with 71 additions and 21 deletions
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17
examples/signals/signals.go
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@ -18,19 +18,24 @@ func main() {
// Go signal notification works by sending `os.Signal`
// values on a channel. We'll create a channel to
// receive these notifications (we'll also make one to
// notify us when the program can exit).
// receive these notifications. Note that this channel
// should be buffered.
sigs := make(chan os.Signal, 1)
done := make(chan bool, 1)
// `signal.Notify` registers the given channel to
// receive notifications of the specified signals.
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
// This goroutine executes a blocking receive for
// signals. When it gets one it'll print it out
// and then notify the program that it can finish.
// We could receive from `sigs` here in the main
// function, but let's see how this could also be
// done in a separate goroutine, to demonstrate
// a more realistic scenario of graceful shutdown.
done := make(chan bool, 1)
go func() {
// This goroutine executes a blocking receive for
// signals. When it gets one it'll print it out
// and then notify the program that it can finish.
sig := <-sigs
fmt.Println()
fmt.Println(sig)

4
examples/signals/signals.hash
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@ -1,2 +1,2 @@
ccee3fe41771b7cf56d64de38b12588022458154
YRV64KEXJW1
cd15508731199185f3205692af0f80cbdee4fcd7
LauPuRo3v9l

6
examples/testing/main_test.go
View File

@ -66,3 +66,9 @@ func TestIntMinTableDriven(t *testing.T) {
})
}
}
func BenchmarkIntMin(b *testing.B) {
for i := 0; i < b.N; i++ {
IntMin(1, 2)
}
}

4
examples/testing/testing.hash
View File

@ -1,2 +1,2 @@
c9ca6b71d9f762b689f1f08a490d8c7f7764fcb3
vY8PN0c6BSx
25e8941d63b555a590e6d44a95ae0e41ecadadca
ALL2BVLkYEr

40
public/signals generated
View File

@ -46,7 +46,7 @@ Here&rsquo;s how to handle signals in Go with channels.</p>
</td>
<td class="code leading">
<a href="http://play.golang.org/p/YRV64KEXJW1"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<a href="http://play.golang.org/p/LauPuRo3v9l"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre>
</td>
@ -83,15 +83,14 @@ Here&rsquo;s how to handle signals in Go with channels.</p>
<td class="docs">
<p>Go signal notification works by sending <code>os.Signal</code>
values on a channel. We&rsquo;ll create a channel to
receive these notifications (we&rsquo;ll also make one to
notify us when the program can exit).</p>
receive these notifications. Note that this channel
should be buffered.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">sigs</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Signal</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="nx">done</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="kt">bool</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
</pre>
</td>
</tr>
@ -110,6 +109,22 @@ receive notifications of the specified signals.</p>
</td>
</tr>
<tr>
<td class="docs">
<p>We could receive from <code>sigs</code> here in the main
function, but let&rsquo;s see how this could also be
done in a separate goroutine, to demonstrate
a more realistic scenario of graceful shutdown.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">done</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="kt">bool</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>This goroutine executes a blocking receive for
@ -119,9 +134,18 @@ and then notify the program that it can finish.</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="k">go</span> <span class="kd">func</span><span class="p">()</span> <span class="p">{</span>
<span class="nx">sig</span> <span class="o">:=</span> <span class="o">&lt;-</span><span class="nx">sigs</span>
<pre class="chroma"> <span class="k">go</span> <span class="kd">func</span><span class="p">()</span> <span class="p">{</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"> <span class="nx">sig</span> <span class="o">:=</span> <span class="o">&lt;-</span><span class="nx">sigs</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">()</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">sig</span><span class="p">)</span>
<span class="nx">done</span> <span class="o">&lt;-</span> <span class="kc">true</span>
@ -186,7 +210,7 @@ causing the program to print <code>interrupt</code> and then exit.</p>
</div>
<script>
var codeLines = [];
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"os\"\u000A \"os/signal\"\u000A \"syscall\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push(' sigs :\u003D make(chan os.Signal, 1)\u000A done :\u003D make(chan bool, 1)\u000A');codeLines.push(' signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)\u000A');codeLines.push(' go func() {\u000A sig :\u003D \u003C-sigs\u000A fmt.Println()\u000A fmt.Println(sig)\u000A done \u003C- true\u000A }()\u000A');codeLines.push(' fmt.Println(\"awaiting signal\")\u000A \u003C-done\u000A fmt.Println(\"exiting\")\u000A}\u000A');codeLines.push('');
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"os\"\u000A \"os/signal\"\u000A \"syscall\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push(' sigs :\u003D make(chan os.Signal, 1)\u000A');codeLines.push(' signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)\u000A');codeLines.push(' done :\u003D make(chan bool, 1)\u000A');codeLines.push(' go func() {\u000A');codeLines.push(' sig :\u003D \u003C-sigs\u000A fmt.Println()\u000A fmt.Println(sig)\u000A done \u003C- true\u000A }()\u000A');codeLines.push(' fmt.Println(\"awaiting signal\")\u000A \u003C-done\u000A fmt.Println(\"exiting\")\u000A}\u000A');codeLines.push('');
</script>
<script src="site.js" async></script>
</body>

21
public/testing generated
View File

@ -47,7 +47,7 @@ typically lives in the same package as the code it tests.</p>
</td>
<td class="code leading">
<a href="http://play.golang.org/p/vY8PN0c6BSx"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<a href="http://play.golang.org/p/ALL2BVLkYEr"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma">
<span class="kn">package</span> <span class="nx">main</span>
</pre>
@ -167,7 +167,7 @@ when executing <code>go test -v</code>.</p>
<td class="docs">
</td>
<td class="code">
<td class="code leading">
<pre class="chroma"> <span class="nx">testname</span> <span class="o">:=</span> <span class="nx">fmt</span><span class="p">.</span><span class="nf">Sprintf</span><span class="p">(</span><span class="s">&#34;%d,%d&#34;</span><span class="p">,</span> <span class="nx">tt</span><span class="p">.</span><span class="nx">a</span><span class="p">,</span> <span class="nx">tt</span><span class="p">.</span><span class="nx">b</span><span class="p">)</span>
<span class="nx">t</span><span class="p">.</span><span class="nf">Run</span><span class="p">(</span><span class="nx">testname</span><span class="p">,</span> <span class="kd">func</span><span class="p">(</span><span class="nx">t</span> <span class="o">*</span><span class="nx">testing</span><span class="p">.</span><span class="nx">T</span><span class="p">)</span> <span class="p">{</span>
@ -178,6 +178,21 @@ when executing <code>go test -v</code>.</p>
<span class="p">})</span>
<span class="p">}</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code">
<pre class="chroma"><span class="kd">func</span> <span class="nf">BenchmarkIntMin</span><span class="p">(</span><span class="nx">b</span> <span class="o">*</span><span class="nx">testing</span><span class="p">.</span><span class="nx">B</span><span class="p">)</span> <span class="p">{</span>
<span class="k">for</span> <span class="nx">i</span> <span class="o">:=</span> <span class="mi">0</span><span class="p">;</span> <span class="nx">i</span> <span class="p">&lt;</span> <span class="nx">b</span><span class="p">.</span><span class="nx">N</span><span class="p">;</span> <span class="nx">i</span><span class="o">++</span> <span class="p">{</span>
<span class="nf">IntMin</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span>
<span class="p">}</span>
<span class="p">}</span>
</pre>
</td>
</tr>
@ -229,7 +244,7 @@ when executing <code>go test -v</code>.</p>
</div>
<script>
var codeLines = [];
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"testing\"\u000A)\u000A');codeLines.push('func IntMin(a, b int) int {\u000A if a \u003C b {\u000A return a\u000A }\u000A return b\u000A}\u000A');codeLines.push('func TestIntMinBasic(t *testing.T) {\u000A ans :\u003D IntMin(2, -2)\u000A if ans !\u003D -2 {\u000A');codeLines.push(' t.Errorf(\"IntMin(2, -2) \u003D %d; want -2\", ans)\u000A }\u000A}\u000A');codeLines.push('func TestIntMinTableDriven(t *testing.T) {\u000A var tests \u003D []struct {\u000A a, b int\u000A want int\u000A }{\u000A {0, 1, 0},\u000A {1, 0, 0},\u000A {2, -2, -2},\u000A {0, -1, -1},\u000A {-1, 0, -1},\u000A }\u000A');codeLines.push(' for _, tt :\u003D range tests {\u000A');codeLines.push(' testname :\u003D fmt.Sprintf(\"%d,%d\", tt.a, tt.b)\u000A t.Run(testname, func(t *testing.T) {\u000A ans :\u003D IntMin(tt.a, tt.b)\u000A if ans !\u003D tt.want {\u000A t.Errorf(\"got %d, want %d\", ans, tt.want)\u000A }\u000A })\u000A }\u000A}\u000A');codeLines.push('');
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"testing\"\u000A)\u000A');codeLines.push('func IntMin(a, b int) int {\u000A if a \u003C b {\u000A return a\u000A }\u000A return b\u000A}\u000A');codeLines.push('func TestIntMinBasic(t *testing.T) {\u000A ans :\u003D IntMin(2, -2)\u000A if ans !\u003D -2 {\u000A');codeLines.push(' t.Errorf(\"IntMin(2, -2) \u003D %d; want -2\", ans)\u000A }\u000A}\u000A');codeLines.push('func TestIntMinTableDriven(t *testing.T) {\u000A var tests \u003D []struct {\u000A a, b int\u000A want int\u000A }{\u000A {0, 1, 0},\u000A {1, 0, 0},\u000A {2, -2, -2},\u000A {0, -1, -1},\u000A {-1, 0, -1},\u000A }\u000A');codeLines.push(' for _, tt :\u003D range tests {\u000A');codeLines.push(' testname :\u003D fmt.Sprintf(\"%d,%d\", tt.a, tt.b)\u000A t.Run(testname, func(t *testing.T) {\u000A ans :\u003D IntMin(tt.a, tt.b)\u000A if ans !\u003D tt.want {\u000A t.Errorf(\"got %d, want %d\", ans, tt.want)\u000A }\u000A })\u000A }\u000A}\u000A');codeLines.push('func BenchmarkIntMin(b *testing.B) {\u000A for i :\u003D 0; i \u003C b.N; i++ {\u000A IntMin(1, 2)\u000A }\u000A}\u000A');codeLines.push('');
</script>
<script src="site.js" async></script>
</body>