k8s.io/kubernetes@v1.29.3/pkg/kubelet/images/helpers.go (about)

     1  /*
     2  Copyright 2016 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 images
    18  
    19  import (
    20  	"context"
    21  	"fmt"
    22  
    23  	v1 "k8s.io/api/core/v1"
    24  	"k8s.io/client-go/util/flowcontrol"
    25  	runtimeapi "k8s.io/cri-api/pkg/apis/runtime/v1"
    26  	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
    27  )
    28  
    29  // throttleImagePulling wraps kubecontainer.ImageService to throttle image
    30  // pulling based on the given QPS and burst limits. If QPS is zero, defaults
    31  // to no throttling.
    32  func throttleImagePulling(imageService kubecontainer.ImageService, qps float32, burst int) kubecontainer.ImageService {
    33  	if qps == 0.0 {
    34  		return imageService
    35  	}
    36  	return &throttledImageService{
    37  		ImageService: imageService,
    38  		limiter:      flowcontrol.NewTokenBucketRateLimiter(qps, burst),
    39  	}
    40  }
    41  
    42  type throttledImageService struct {
    43  	kubecontainer.ImageService
    44  	limiter flowcontrol.RateLimiter
    45  }
    46  
    47  func (ts throttledImageService) PullImage(ctx context.Context, image kubecontainer.ImageSpec, secrets []v1.Secret, podSandboxConfig *runtimeapi.PodSandboxConfig) (string, error) {
    48  	if ts.limiter.TryAccept() {
    49  		return ts.ImageService.PullImage(ctx, image, secrets, podSandboxConfig)
    50  	}
    51  	return "", fmt.Errorf("pull QPS exceeded")
    52  }