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Below is an example of controlling multiple processes/threads using golang.
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package main | |
import ( | |
"log" | |
"os" | |
"os/signal" | |
"sync" | |
"time" | |
) | |
type MySyncCond struct { | |
*sync.Cond | |
Kill bool | |
Payload int | |
} | |
func (m *MySyncCond) Init() { | |
m.Kill = false | |
} | |
// Extend Broadcast to allow a payload | |
func (m *MySyncCond) Broadcast(payload int) { | |
// set the new payload before broadcasting | |
m.Payload = payload | |
log.Println("Calling real broadcast") | |
m.Cond.Broadcast() | |
} | |
func pinger(c *MySyncCond, wg *sync.WaitGroup) { | |
defer wg.Done() | |
defer c.L.Unlock() | |
defer log.Println("Terminated pinger") | |
kill := make(chan os.Signal) | |
signal.Notify(kill) | |
count := 0 | |
for { | |
select { | |
case <-kill: | |
log.Println("Kill caught") | |
c.Kill = true | |
c.Cond.Broadcast() | |
break | |
default: | |
count += 1 | |
log.Printf("Pinger Pings: %d\n", count) | |
c.Broadcast(count) | |
time.Sleep(5 * time.Second) | |
} | |
} | |
} | |
func divByOne(c *MySyncCond, wg *sync.WaitGroup) { | |
defer wg.Done() | |
defer log.Printf("Terminated divByOne") | |
defer c.L.Unlock() // make sure we unlock | |
for { | |
c.L.Lock() | |
c.Wait() | |
if c.Kill { | |
break | |
} | |
if c.Payload%1 == 0 { | |
log.Printf("One\n") | |
} | |
c.L.Unlock() | |
} | |
} | |
func divByTwo(c *MySyncCond, wg *sync.WaitGroup) { | |
defer wg.Done() | |
defer c.L.Unlock() // make sure we unlock | |
defer log.Println("Terminated divByTwo") | |
for { | |
c.L.Lock() | |
c.Wait() | |
if c.Kill { | |
break | |
} | |
if c.Payload%2 == 0 { | |
log.Printf("Two\n") | |
} | |
c.L.Unlock() | |
} | |
} | |
func divByThree(c *MySyncCond, wg *sync.WaitGroup) { | |
defer wg.Done() | |
defer c.L.Unlock() | |
defer log.Println("Terminated divByThree") | |
for { | |
c.L.Lock() | |
c.Wait() | |
if c.Kill { | |
break | |
} | |
if c.Payload%3 == 0 { | |
log.Printf("Three\n") | |
} | |
c.L.Unlock() | |
} | |
} | |
func main() { | |
logfile, err := os.OpenFile("/tmp/condfun.log", os.O_CREATE|os.O_APPEND|os.O_RDWR, 0644) | |
if err != nil { | |
log.Fatal(err) | |
} | |
log.SetOutput(logfile) | |
defer logfile.Close() | |
c := MySyncCond{sync.NewCond(new(sync.Mutex)), false, 0} | |
done := make(chan bool) | |
kill := make(chan os.Signal) | |
defer close(kill) | |
signal.Notify(kill) | |
var wg sync.WaitGroup | |
wg.Add(4) | |
go pinger(&c, &wg) | |
go divByOne(&c, &wg) | |
go divByTwo(&c, &wg) | |
go divByThree(&c, &wg) | |
go func(wg *sync.WaitGroup, done chan bool) { | |
defer close(done) | |
log.Println("Once: Waiting") | |
wg.Wait() | |
log.Println("Once: Done") | |
done <- true | |
}(&wg, done) | |
log.Println("Back in main") | |
<-kill | |
log.Println("Kill Seen") | |
c.Kill = true | |
c.Cond.Broadcast() | |
log.Println("Terminated Main") | |
} |
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