102 lines
3.2 KiB
Go
102 lines
3.2 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package dockertools
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import (
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"fmt"
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"sync"
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"github.com/golang/glog"
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dockertypes "github.com/docker/engine-api/types"
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runtime "k8s.io/kubernetes/pkg/kubelet/container"
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)
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// imageStatsProvider exposes stats about all images currently available.
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type imageStatsProvider struct {
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sync.Mutex
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// layers caches the current layers, key is the layer ID.
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layers map[string]*dockertypes.ImageHistory
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// imageToLayerIDs maps image to its layer IDs.
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imageToLayerIDs map[string][]string
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// Docker remote API client
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c DockerInterface
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}
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func newImageStatsProvider(c DockerInterface) *imageStatsProvider {
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return &imageStatsProvider{
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layers: make(map[string]*dockertypes.ImageHistory),
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imageToLayerIDs: make(map[string][]string),
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c: c,
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}
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}
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func (isp *imageStatsProvider) ImageStats() (*runtime.ImageStats, error) {
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images, err := isp.c.ListImages(dockertypes.ImageListOptions{})
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if err != nil {
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return nil, fmt.Errorf("failed to list docker images - %v", err)
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}
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// Take the lock to protect the cache
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isp.Lock()
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defer isp.Unlock()
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// Create new cache each time, this is a little more memory consuming, but:
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// * ImageStats is only called every 10 seconds
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// * We use pointers and reference to copy cache elements.
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// The memory usage should be acceptable.
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// TODO(random-liu): Add more logic to implement in place cache update.
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newLayers := make(map[string]*dockertypes.ImageHistory)
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newImageToLayerIDs := make(map[string][]string)
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for _, image := range images {
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layerIDs, ok := isp.imageToLayerIDs[image.ID]
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if !ok {
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// Get information about the various layers of the given docker image.
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history, err := isp.c.ImageHistory(image.ID)
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if err != nil {
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// Skip the image and inspect again in next ImageStats if the image is still there
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glog.V(2).Infof("failed to get history of docker image %+v - %v", image, err)
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continue
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}
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// Cache each layer
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for i := range history {
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layer := &history[i]
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key := layer.ID
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// Some of the layers are empty.
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// We are hoping that these layers are unique to each image.
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// Still keying with the CreatedBy field to be safe.
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if key == "" || key == "<missing>" {
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key = key + layer.CreatedBy
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}
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layerIDs = append(layerIDs, key)
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newLayers[key] = layer
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}
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} else {
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for _, layerID := range layerIDs {
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newLayers[layerID] = isp.layers[layerID]
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}
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}
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newImageToLayerIDs[image.ID] = layerIDs
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}
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ret := &runtime.ImageStats{}
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// Calculate the total storage bytes
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for _, layer := range newLayers {
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ret.TotalStorageBytes += uint64(layer.Size)
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}
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// Update current cache
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isp.layers = newLayers
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isp.imageToLayerIDs = newImageToLayerIDs
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return ret, nil
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}
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