sigs.k8s.io/cluster-api-provider-aws@v1.5.5/pkg/cloud/services/wait/wait.go (about)

     1  /*
     2  Copyright 2018 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8  	http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package wait
    18  
    19  import (
    20  	"time"
    21  
    22  	"github.com/pkg/errors"
    23  	"k8s.io/apimachinery/pkg/util/wait"
    24  
    25  	"sigs.k8s.io/cluster-api-provider-aws/pkg/cloud/awserrors"
    26  )
    27  
    28  /*
    29   Ideally, this entire file would be replaced with returning a retryable
    30   error and letting the actuator requeue deletion. Unfortunately, since
    31   the retry behaviour is not tunable, with a max retry limit of 10, we
    32   implement waits manually here.
    33  */
    34  
    35  // NewBackoff creates a new API Machinery backoff parameter set suitable
    36  // for use with AWS services.
    37  func NewBackoff() wait.Backoff {
    38  	// Return a exponential backoff configuration which
    39  	// returns durations for a total time of ~5m.
    40  	// Example: 1s, 1.7s, 2.9s, 5s, 8.6s, 14.6s, 25s, 42.8s, 73.1s ... 125s
    41  	// Jitter is added as a random fraction of the duration multiplied by the
    42  	// jitter factor.
    43  	return wait.Backoff{
    44  		Duration: time.Second,
    45  		Factor:   1.71,
    46  		Steps:    10,
    47  		Jitter:   0.4,
    48  	}
    49  }
    50  
    51  // WaitForWithRetryable repeats a condition check with exponential backoff.
    52  func WaitForWithRetryable(backoff wait.Backoff, condition wait.ConditionFunc, retryableErrors ...string) error {
    53  	var errToReturn error
    54  	waitErr := wait.ExponentialBackoff(backoff, func() (bool, error) {
    55  		// clear errToReturn value from previous iteration
    56  		errToReturn = nil
    57  
    58  		ok, err := condition()
    59  		if ok {
    60  			// All done!
    61  			return true, nil
    62  		}
    63  		if err == nil {
    64  			// Not done, but no error, so keep waiting.
    65  			return false, nil
    66  		}
    67  
    68  		// If the returned error isn't empty, check if the error is a retryable one,
    69  		// or return immediately.
    70  		code, ok := awserrors.Code(errors.Cause(err))
    71  		if !ok {
    72  			return false, err
    73  		}
    74  
    75  		for _, r := range retryableErrors {
    76  			if code == r {
    77  				// We should retry.
    78  				errToReturn = err
    79  				return false, nil
    80  			}
    81  		}
    82  
    83  		// Got an error that we can't retry, so return it.
    84  		return false, err
    85  	})
    86  
    87  	// If the waitError is not a timeout error (nil or a non-retryable error), return it
    88  	if !errors.Is(waitErr, wait.ErrWaitTimeout) {
    89  		return waitErr
    90  	}
    91  
    92  	// A retryable error occurred, return the actual error
    93  	if errToReturn != nil {
    94  		return errToReturn
    95  	}
    96  
    97  	// The error was timeout error
    98  	return waitErr
    99  }