github.com/m3db/m3@v1.5.0/src/x/retry/example_test.go (about)

     1  // Copyright (c) 2017 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package retry_test
    22  
    23  import (
    24  	"context"
    25  	"errors"
    26  	"fmt"
    27  	"log"
    28  
    29  	"github.com/m3db/m3/src/x/retry"
    30  )
    31  
    32  func ExampleRetrier() {
    33  	var (
    34  		opts    = retry.NewOptions()
    35  		retrier = retry.NewRetrier(opts)
    36  		context = context.Background()
    37  	)
    38  
    39  	continueFn := func(attempt int) bool {
    40  		// Check if the context has been canceled.
    41  		select {
    42  		case <-context.Done():
    43  			return false
    44  		default:
    45  			return true
    46  		}
    47  	}
    48  
    49  	var attempts int
    50  	fn := func() error {
    51  		// Perform some work which may fail.
    52  
    53  		if attempts++; attempts == 3 {
    54  			fmt.Printf("Attempt %v succeeded", attempts)
    55  			// Output: Attempt 3 succeeded
    56  
    57  			return nil
    58  		}
    59  		return errors.New("test")
    60  	}
    61  
    62  	if err := retrier.AttemptWhile(continueFn, fn); err != nil {
    63  		log.Fatal(err)
    64  	}
    65  
    66  }