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doc/codewalk: update urlpoll to use time.Duration.

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R=adg
CC=golang-dev
https://golang.org/cl/5545061
This commit is contained in:
Stefan Nilsson 2012-01-19 14:45:59 +11:00 committed by Andrew Gerrand
parent 885cbc3be4
commit 1de4931113
1 changed files with 12 additions and 13 deletions
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25
doc/codewalk/urlpoll.go
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@ -11,11 +11,10 @@ import (
)
const (
numPollers = 2 // number of Poller goroutines to launch
second = 1e9 // one second is 1e9 nanoseconds
pollInterval = 60 * second // how often to poll each URL
statusInterval = 10 * second // how often to log status to stdout
errTimeout = 10 * second // back-off timeout on error
numPollers = 2 // number of Poller goroutines to launch
pollInterval = 60 * time.Second // how often to poll each URL
statusInterval = 10 * time.Second // how often to log status to stdout
errTimeout = 10 * time.Second // back-off timeout on error
)
var urls = []string{
@ -33,7 +32,7 @@ type State struct {
// StateMonitor maintains a map that stores the state of the URLs being
// polled, and prints the current state every updateInterval nanoseconds.
// It returns a chan State to which resource state should be sent.
func StateMonitor(updateInterval int64) chan<- State {
func StateMonitor(updateInterval time.Duration) chan<- State {
updates := make(chan State)
urlStatus := make(map[string]string)
ticker := time.NewTicker(updateInterval)
@ -61,7 +60,7 @@ func logState(s map[string]string) {
// Resource represents an HTTP URL to be polled by this program.
type Resource struct {
url string
errCount int64
errCount int
}
// Poll executes an HTTP HEAD request for url
@ -79,8 +78,8 @@ func (r *Resource) Poll() string {
// Sleep sleeps for an appropriate interval (dependant on error state)
// before sending the Resource to done.
func (r *Resource) Sleep(done chan *Resource) {
time.Sleep(pollInterval + errTimeout*r.errCount)
func (r *Resource) Sleep(done chan<- *Resource) {
time.Sleep(pollInterval + errTimeout*time.Duration(r.errCount))
done <- r
}
@ -93,18 +92,18 @@ func Poller(in <-chan *Resource, out chan<- *Resource, status chan<- State) {
}
func main() {
// create our input and output channels
// Create our input and output channels.
pending, complete := make(chan *Resource), make(chan *Resource)
// launch the StateMonitor
// Launch the StateMonitor.
status := StateMonitor(statusInterval)
// launch some Poller goroutines
// Launch some Poller goroutines.
for i := 0; i < numPollers; i++ {
go Poller(pending, complete, status)
}
// send some Resources to the pending queue
// Send some Resources to the pending queue.
go func() {
for _, url := range urls {
pending <- &Resource{url: url}