k8s.io/apiserver@v0.31.1/pkg/server/storage_readiness_hook.go (about)

     1  /*
     2  Copyright 2024 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 server
    18  
    19  import (
    20  	"context"
    21  	"errors"
    22  	"sync"
    23  	"time"
    24  
    25  	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    26  	"k8s.io/apimachinery/pkg/util/wait"
    27  	"k8s.io/apiserver/pkg/registry/rest"
    28  	"k8s.io/klog/v2"
    29  )
    30  
    31  // StorageReadinessHook implements PostStartHook functionality for checking readiness
    32  // of underlying storage for registered resources.
    33  type StorageReadinessHook struct {
    34  	timeout time.Duration
    35  
    36  	lock   sync.Mutex
    37  	checks map[string]func() error
    38  }
    39  
    40  // NewStorageReadinessHook created new StorageReadinessHook.
    41  func NewStorageReadinessHook(timeout time.Duration) *StorageReadinessHook {
    42  	return &StorageReadinessHook{
    43  		checks:  make(map[string]func() error),
    44  		timeout: timeout,
    45  	}
    46  }
    47  
    48  func (h *StorageReadinessHook) RegisterStorage(gvr metav1.GroupVersionResource, storage rest.StorageWithReadiness) {
    49  	h.lock.Lock()
    50  	defer h.lock.Unlock()
    51  
    52  	if _, ok := h.checks[gvr.String()]; !ok {
    53  		h.checks[gvr.String()] = storage.ReadinessCheck
    54  	} else {
    55  		klog.Errorf("Registering storage readiness hook for %s again: ", gvr.String())
    56  	}
    57  }
    58  
    59  func (h *StorageReadinessHook) check() bool {
    60  	h.lock.Lock()
    61  	defer h.lock.Unlock()
    62  
    63  	failedChecks := []string{}
    64  	for gvr, check := range h.checks {
    65  		if err := check(); err != nil {
    66  			failedChecks = append(failedChecks, gvr)
    67  		}
    68  	}
    69  	if len(failedChecks) == 0 {
    70  		klog.Infof("Storage is ready for all registered resources")
    71  		return true
    72  	}
    73  	klog.V(4).Infof("Storage is not ready for: %v", failedChecks)
    74  	return false
    75  }
    76  
    77  func (h *StorageReadinessHook) Hook(ctx PostStartHookContext) error {
    78  	deadlineCtx, cancel := context.WithTimeout(ctx, h.timeout)
    79  	defer cancel()
    80  	err := wait.PollUntilContextCancel(deadlineCtx, 100*time.Millisecond, true,
    81  		func(_ context.Context) (bool, error) {
    82  			if ok := h.check(); ok {
    83  				return true, nil
    84  			}
    85  			return false, nil
    86  		})
    87  	if errors.Is(err, context.DeadlineExceeded) {
    88  		klog.Warningf("Deadline exceeded while waiting for storage readiness... ignoring")
    89  	}
    90  	return nil
    91  }