github.com/jenkins-x/jx/v2@v2.1.155/pkg/tests/retry.go (about)

     1  // Copyright 2019 Google LLC
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     https://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package tests
    16  
    17  import (
    18  	"bytes"
    19  	"fmt"
    20  	"path/filepath"
    21  	"runtime"
    22  	"strconv"
    23  	"testing"
    24  	"time"
    25  )
    26  
    27  // Retry runs function f for up to maxAttempts times until f returns successfully, and reports whether f was run successfully.
    28  // It will sleep for the given period between invocations of f.
    29  // Use the provided *tests.R instead of a *testing.T from the function.
    30  func Retry(t *testing.T, maxAttempts int, sleep time.Duration, f func(r *R)) bool {
    31  	for attempt := 1; attempt <= maxAttempts; attempt++ {
    32  		r := &R{Attempt: attempt, log: &bytes.Buffer{}}
    33  
    34  		f(r)
    35  
    36  		if !r.failed {
    37  			if r.log.Len() != 0 {
    38  				t.Logf("Success after %d attempts:%s", attempt, r.log.String())
    39  			}
    40  			return true
    41  		}
    42  
    43  		if attempt == maxAttempts {
    44  			t.Logf("FAILED after %d attempts:%s", attempt, r.log.String())
    45  			t.Fail()
    46  		}
    47  
    48  		time.Sleep(sleep)
    49  	}
    50  	return false
    51  }
    52  
    53  // R is passed to each run of a flaky test run, manages state and accumulates log statements.
    54  type R struct {
    55  	// The number of current attempt.
    56  	Attempt int
    57  
    58  	failed bool
    59  	log    *bytes.Buffer
    60  }
    61  
    62  // Fail marks the run as failed, and will retry once the function returns.
    63  func (r *R) Fail() {
    64  	r.failed = true
    65  }
    66  
    67  // Errorf is equivalent to Logf followed by Fail.
    68  func (r *R) Errorf(s string, v ...interface{}) {
    69  	r.logf(s, v...)
    70  	r.Fail()
    71  }
    72  
    73  // Logf formats its arguments and records it in the error log.
    74  // The text is only printed for the final unsuccessful run or the first successful run.
    75  func (r *R) Logf(s string, v ...interface{}) {
    76  	r.logf(s, v...)
    77  }
    78  
    79  func (r *R) logf(s string, v ...interface{}) {
    80  	fmt.Fprint(r.log, "\n")
    81  	fmt.Fprint(r.log, lineNumber())
    82  	fmt.Fprintf(r.log, s, v...)
    83  }
    84  
    85  func lineNumber() string {
    86  	_, file, line, ok := runtime.Caller(3) // logf, public func, user function
    87  	if !ok {
    88  		return ""
    89  	}
    90  	return filepath.Base(file) + ":" + strconv.Itoa(line) + ": "
    91  }