60 lines
1.0 KiB
Go
60 lines
1.0 KiB
Go
package main
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import (
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"fmt"
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"sync"
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"github.com/dwrz/talks/concurrency/pkg/weather"
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)
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const (
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// Hardcoded padding for longest city name, Philadelphia.
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message = "%-12s %.2f°F\n"
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)
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func printTemperatures(cities []string) {
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for _, city := range cities {
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cityWeather, err := weather.GetCity(city)
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if err != nil {
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fmt.Printf(
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"error getting weather for %s: %v\n", city, err,
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)
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continue
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}
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fmt.Printf(message, city, cityWeather.Temp)
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}
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}
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func printTemperaturesAsync(cities []string) {
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var weatherReports = make(chan string, len(cities))
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var wg sync.WaitGroup
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wg.Add(len(cities))
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for _, city := range cities {
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go func(city string) {
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defer wg.Done()
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cityWeather, err := weather.GetCity(city)
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if err != nil {
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fmt.Printf(
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"error getting weather for %s: %v\n",
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city, err,
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)
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return
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}
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weatherReports <- fmt.Sprintf(
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message, city, cityWeather.Temp,
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)
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}(city)
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}
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wg.Wait()
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close(weatherReports)
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for report := range weatherReports {
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fmt.Print(report)
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}
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}
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