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package throttler
import "fmt"
type httpPkg struct{}
func (httpPkg) Get(url string) error { return nil }
var http httpPkg
// This example fetches several URLs concurrently,
// using a Throttler to block until all the fetches are complete.
// Compare to http://golang.org/pkg/sync/#example_WaitGroup
func ExampleThrottler() {
var urls = []string{
"http://www.golang.org/",
"http://www.google.com/",
"http://www.somestupidname.com/",
}
// Create a new Throttler that will get 2 urls at a time
t := New(2, len(urls))
for _, url := range urls {
// Launch a goroutine to fetch the URL.
go func(url string) {
// Fetch the URL.
err := http.Get(url)
// Let Throttler know when the goroutine completes
// so it can dispatch another worker
t.Done(err)
}(url)
// Pauses until a worker is available or all jobs have been completed
// Returning the total number of goroutines that have errored
// lets you choose to break out of the loop without starting any more
errorCount := t.Throttle()
if errorCount > 0 {
break
}
}
}
// This example fetches several URLs concurrently,
// using a Throttler to block until all the fetches are complete
// and checks the errors returned.
// Compare to http://golang.org/pkg/sync/#example_WaitGroup
func ExampleThrottler_errors() error {
var urls = []string{
"http://www.golang.org/",
"http://www.google.com/",
"http://www.somestupidname.com/",
}
// Create a new Throttler that will get 2 urls at a time
t := New(2, len(urls))
for _, url := range urls {
// Launch a goroutine to fetch the URL.
go func(url string) {
// Let Throttler know when the goroutine completes
// so it can dispatch another worker
defer t.Done(nil)
// Fetch the URL.
http.Get(url)
}(url)
// Pauses until a worker is available or all jobs have been completed
t.Throttle()
}
if t.Err() != nil {
// Loop through the errors to see the details
for i, err := range t.Errs() {
fmt.Printf("error #%d: %s", i, err)
}
return t.Err()
}
return nil
}
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