github.com/graybobo/golang.org-package-offline-cache@v0.0.0-20200626051047-6608995c132f/x/talks/2014/gotham-context/first.go (about)

     1  // +build OMIT
     2  
     3  package main
     4  
     5  import (
     6  	"fmt"
     7  	"math/rand"
     8  	"time"
     9  )
    10  
    11  // START1 OMIT
    12  // Search runs query on a backend and returns the result.
    13  type Search func(query string) Result
    14  type Result struct {
    15  	Hit string
    16  	Err error
    17  }
    18  
    19  // First runs query on replicas and returns the first result.
    20  func First(query string, replicas ...Search) Result {
    21  	c := make(chan Result, len(replicas))
    22  	search := func(replica Search) { c <- replica(query) }
    23  	for _, replica := range replicas {
    24  		go search(replica)
    25  	}
    26  	return <-c
    27  }
    28  
    29  // STOP1 OMIT
    30  
    31  // START2 OMIT
    32  func main() {
    33  	rand.Seed(time.Now().UnixNano())
    34  	start := time.Now()
    35  	result := First("golang",
    36  		fakeSearch("replica 1"),
    37  		fakeSearch("replica 2"))
    38  	elapsed := time.Since(start)
    39  	fmt.Printf("%+v\n", result)
    40  	fmt.Println(elapsed)
    41  }
    42  
    43  // STOP2 OMIT
    44  
    45  func fakeSearch(kind string) Search {
    46  	return func(query string) Result {
    47  		time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
    48  		return Result{Hit: fmt.Sprintf("%s result for %q\n", kind, query)}
    49  	}
    50  }