retry_test.go

Documentation: cloud.google.com/go/cloudsqlconn/internal/cloudsql

     1  // Copyright 2024 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 cloudsql
    16  
    17  import (
    18  	"context"
    19  	"errors"
    20  	"fmt"
    21  	"testing"
    22  	"time"
    23  
    24  	"google.golang.org/api/googleapi"
    25  )
    26  
    27  func TestRetryExponentialBackoff(t *testing.T) {
    28  	tcs := []struct {
    29  		attempt int
    30  		// The resulting backoff value should be >= low or <= high
    31  		low  time.Duration
    32  		high time.Duration
    33  	}{
    34  		{
    35  			attempt: 0,
    36  			low:     324 * time.Millisecond,
    37  			high:    524 * time.Millisecond,
    38  		},
    39  		{
    40  			attempt: 1,
    41  			low:     524 * time.Millisecond,
    42  			high:    847 * time.Millisecond,
    43  		},
    44  		{
    45  			attempt: 2,
    46  			low:     847 * time.Millisecond,
    47  			high:    1371 * time.Millisecond,
    48  		},
    49  		{
    50  			attempt: 3,
    51  			low:     1371 * time.Millisecond,
    52  			high:    2218 * time.Millisecond,
    53  		},
    54  		{
    55  			attempt: 4,
    56  			low:     2218 * time.Millisecond,
    57  			high:    3588 * time.Millisecond,
    58  		},
    59  	}
    60  
    61  	for _, tc := range tcs {
    62  		t.Run(fmt.Sprintf("attempt %d", tc.attempt), func(t *testing.T) {
    63  			got := exponentialBackoff(tc.attempt)
    64  			got = got.Round(time.Millisecond)
    65  			if got < tc.low {
    66  				t.Fatalf("got was below lower bound, got = %v, want = %v",
    67  					got, tc.low,
    68  				)
    69  			}
    70  			if got > tc.high {
    71  				t.Fatalf("got was above upper bound, got = %v, want = %v",
    72  					got, tc.high,
    73  				)
    74  			}
    75  		})
    76  	}
    77  }
    78  
    79  func TestRetry(t *testing.T) {
    80  	tcs := []struct {
    81  		desc      string
    82  		f         func(context.Context) (*any, error)
    83  		wantCount int
    84  	}{
    85  		{
    86  			desc: "unknown errors are not retried",
    87  			f: func(context.Context) (*any, error) {
    88  				return nil, errors.New("unknown")
    89  			},
    90  			wantCount: 0,
    91  		},
    92  		{
    93  			desc: "do not retry non-50x responses",
    94  			f: func(context.Context) (*any, error) {
    95  				return nil, &googleapi.Error{
    96  					Code: 400,
    97  				}
    98  			},
    99  			wantCount: 0,
   100  		},
   101  		{
   102  			desc: "retry >= 500 HTTP responses with wait function",
   103  			f: func(context.Context) (*any, error) {
   104  				return nil, &googleapi.Error{
   105  					Code: 500,
   106  				}
   107  			},
   108  			wantCount: 5,
   109  		},
   110  		{
   111  			desc: "successful response is not retried",
   112  			f: func(context.Context) (*any, error) {
   113  				// no error means success
   114  				return nil, nil
   115  			},
   116  			wantCount: 0,
   117  		},
   118  	}
   119  	for _, tc := range tcs {
   120  		t.Run(tc.desc, func(t *testing.T) {
   121  			var callCount int
   122  			waitSpy := func(int) time.Duration {
   123  				callCount++
   124  				return time.Microsecond
   125  			}
   126  
   127  			retry50x(context.Background(), tc.f, waitSpy)
   128  
   129  			if callCount != tc.wantCount {
   130  				t.Fatalf(
   131  					"retry call count, want = %v, got = %v",
   132  					tc.wantCount, callCount,
   133  				)
   134  			}
   135  		})
   136  	}
   137  }
   138  
   139  func TestRetryExitsEarlyOnContextCancellation(t *testing.T) {
   140  	ctx, cancel := context.WithCancel(context.Background())
   141  	cancel()
   142  
   143  	fail := func(context.Context) (*any, error) {
   144  		err := &googleapi.Error{
   145  			Code:    500,
   146  			Message: "I always fail",
   147  		}
   148  		return nil, err
   149  	}
   150  	// Context cancellation short-circuits the wait duration
   151  	waitOneHour := func(int) time.Duration { return time.Hour }
   152  
   153  	_, err := retry50x(ctx, fail, waitOneHour)
   154  	if !errors.Is(err, context.Canceled) {
   155  		t.Fatalf("want = %v, got = %v", context.Canceled, err)
   156  	}
   157  }
   158
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