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Use cachekey not digest for COPY --from src
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* use the cachekey of the src stage rather than the digest
for COPY --from commands as they are reproducible unlike digests
* track digest to cache keys and stage indexes to digest
* add extra debug logging for troubleshooting cachekey building issues
* convert Sha256 hashes to hex encoded strings rather than plain strings
for easier human reading
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@cvgw
cvgw committed Dec 10, 2019
1 parent 7b4b768 commit b19214a
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Showing 3 changed files with 63 additions and 100 deletions.
109 changes: 59 additions & 50 deletions pkg/executor/build.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,23 +61,24 @@ type snapShotter interface {

// stageBuilder contains all fields necessary to build one stage of a Dockerfile
type stageBuilder struct {
stage config.KanikoStage
image v1.Image
cf *v1.ConfigFile
baseImageDigest string
finalCacheKey string
opts *config.KanikoOptions
cmds []commands.DockerCommand
args *dockerfile.BuildArgs
crossStageDeps map[int][]string
digestToCacheKeyMap map[string]string
snapshotter snapShotter
layerCache cache.LayerCache
pushCache cachePusher
stage config.KanikoStage
image v1.Image
cf *v1.ConfigFile
baseImageDigest string
finalCacheKey string
opts *config.KanikoOptions
cmds []commands.DockerCommand
args *dockerfile.BuildArgs
crossStageDeps map[int][]string
digestToCacheKey map[string]string
stageIdxToDigest map[string]string
snapshotter snapShotter
layerCache cache.LayerCache
pushCache cachePusher
}

// newStageBuilder returns a new type stageBuilder which contains all the information required to build the stage
func newStageBuilder(opts *config.KanikoOptions, stage config.KanikoStage, crossStageDeps map[int][]string, dcm map[string]string) (*stageBuilder, error) {
func newStageBuilder(opts *config.KanikoOptions, stage config.KanikoStage, crossStageDeps map[int][]string, dcm map[string]string, sid map[string]string) (*stageBuilder, error) {
sourceImage, err := util.RetrieveSourceImage(stage, opts)
if err != nil {
return nil, err
Expand All @@ -104,14 +105,15 @@ func newStageBuilder(opts *config.KanikoOptions, stage config.KanikoStage, cross
return nil, err
}
s := &stageBuilder{
stage: stage,
image: sourceImage,
cf: imageConfig,
snapshotter: snapshotter,
baseImageDigest: digest.String(),
opts: opts,
crossStageDeps: crossStageDeps,
digestToCacheKeyMap: dcm,
stage: stage,
image: sourceImage,
cf: imageConfig,
snapshotter: snapshotter,
baseImageDigest: digest.String(),
opts: opts,
crossStageDeps: crossStageDeps,
digestToCacheKey: dcm,
stageIdxToDigest: sid,
layerCache: &cache.RegistryCache{
Opts: opts,
},
Expand Down Expand Up @@ -146,28 +148,14 @@ func initializeConfig(img partial.WithConfigFile) (*v1.ConfigFile, error) {
return imageConfig, nil
}

func (s *stageBuilder) populateCompositeKey(command commands.DockerCommand, files []string, compositeKey CompositeCache) (CompositeCache, error) {
func (s *stageBuilder) populateCompositeKey(command fmt.Stringer, files []string, compositeKey CompositeCache) (CompositeCache, error) {
// Add the next command to the cache key.
compositeKey.AddKey(command.String())
switch v := command.(type) {
case *commands.CopyCommand:
if v.From() != "" {
digest, ok := s.digestMap[v.From()]
if ok {
ds := digest.String()
logrus.Debugf("adding digest %v from previous stage to composite key for %v", ds, command.String())
compositeKey.AddKey(ds)
}
}
compositeKey = s.populateCopyCmdCompositeKey(command, v.From(), compositeKey)
case *commands.CachingCopyCommand:
if v.From() != "" {
digest, ok := s.digestMap[v.From()]
if ok {
ds := digest.String()
logrus.Debugf("adding digest %v from previous stage to composite key for %v", ds, command.String())
compositeKey.AddKey(ds)
}
}
compositeKey = s.populateCopyCmdCompositeKey(command, v.From(), compositeKey)
}

for _, f := range files {
Expand All @@ -178,6 +166,22 @@ func (s *stageBuilder) populateCompositeKey(command commands.DockerCommand, file
return compositeKey, nil
}

func (s *stageBuilder) populateCopyCmdCompositeKey(command fmt.Stringer, from string, compositeKey CompositeCache) CompositeCache {
if from != "" {
digest, ok := s.stageIdxToDigest[from]
if ok {
ds := digest
cacheKey, ok := s.digestToCacheKey[ds]
if ok {
logrus.Debugf("adding digest %v from previous stage to composite key for %v", ds, command.String())
compositeKey.AddKey(cacheKey)
}
}
}

return compositeKey
}

func (s *stageBuilder) optimize(compositeKey CompositeCache, cfg v1.Config) error {
if !s.opts.Cache {
return nil
Expand All @@ -202,10 +206,12 @@ func (s *stageBuilder) optimize(compositeKey CompositeCache, cfg v1.Config) erro
return err
}

logrus.Debugf("optimize: composite key for command %v %v", command.String(), compositeKey)
ck, err := compositeKey.Hash()
if err != nil {
return errors.Wrap(err, "failed to hash composite key")
}
logrus.Debugf("optimize: cache key for command %v %v", command.String(), ck)
s.finalCacheKey = ck
if command.ShouldCacheOutput() && !stopCache {
img, err := s.layerCache.RetrieveLayer(ck)
Expand Down Expand Up @@ -236,7 +242,7 @@ func (s *stageBuilder) optimize(compositeKey CompositeCache, cfg v1.Config) erro
func (s *stageBuilder) build() error {
// Set the initial cache key to be the base image digest, the build args and the SrcContext.
var compositeKey *CompositeCache
if cacheKey, ok := s.digestToCacheKeyMap[s.baseImageDigest]; ok {
if cacheKey, ok := s.digestToCacheKey[s.baseImageDigest]; ok {
compositeKey = NewCompositeCache(cacheKey)
} else {
compositeKey = NewCompositeCache(s.baseImageDigest)
Expand Down Expand Up @@ -316,6 +322,7 @@ func (s *stageBuilder) build() error {
return errors.Wrap(err, "failed to take snapshot")
}

logrus.Debugf("build: composite key for command %v %v", command.String(), compositeKey)
ck, err := compositeKey.Hash()
if err != nil {
return errors.Wrap(err, "failed to hash composite key")
Expand Down Expand Up @@ -472,7 +479,8 @@ func CalculateDependencies(opts *config.KanikoOptions) (map[int][]string, error)
// DoBuild executes building the Dockerfile
func DoBuild(opts *config.KanikoOptions) (v1.Image, error) {
t := timing.Start("Total Build Time")
digestToCacheKeyMap := make(map[string]string)
digestToCacheKey := make(map[string]string)
stageIdxToDigest := make(map[string]string)

// Parse dockerfile and unpack base image to root
stages, err := dockerfile.Stages(opts)
Expand All @@ -494,31 +502,32 @@ func DoBuild(opts *config.KanikoOptions) (v1.Image, error) {
logrus.Infof("Built cross stage deps: %v", crossStageDependencies)

for index, stage := range stages {
sb, err := newStageBuilder(opts, stage, crossStageDependencies, digestToCacheKeyMap)
sb, err := newStageBuilder(opts, stage, crossStageDependencies, digestToCacheKey, stageIdxToDigest)
if err != nil {
return nil, err
}
if err := sb.build(); err != nil {
return nil, errors.Wrap(err, "error building stage")
}

d, err := sb.image.Digest()
if err != nil {
return nil, err
}

digestMap[fmt.Sprintf("%d", sb.stage.Index)] = d

reviewConfig(stage, &sb.cf.Config)

sourceImage, err := mutate.Config(sb.image, sb.cf.Config)
if err != nil {
return nil, err
}

d, err := sourceImage.Digest()
if err != nil {
return nil, err
}
digestToCacheKeyMap[d.String()] = sb.finalCacheKey

stageIdxToDigest[fmt.Sprintf("%d", sb.stage.Index)] = d.String()
logrus.Debugf("mapping stage idx %v to digest %v", sb.stage.Index, d.String())

digestToCacheKey[d.String()] = sb.finalCacheKey
logrus.Debugf("mapping digest %v to cachekey %v", d.String(), sb.finalCacheKey)

if stage.Final {
sourceImage, err = mutate.CreatedAt(sourceImage, v1.Time{Time: time.Now()})
if err != nil {
Expand Down
49 changes: 1 addition & 48 deletions pkg/executor/build_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -888,6 +888,7 @@ func tempDirAndFile(t *testing.T) (string, []string) {

return dir, filenames
}

func generateTar(t *testing.T, dir string, fileNames ...string) []byte {
buf := bytes.NewBuffer([]byte{})
writer := tar.NewWriter(buf)
Expand Down Expand Up @@ -919,51 +920,3 @@ func generateTar(t *testing.T, dir string, fileNames ...string) []byte {
}
return buf.Bytes()
}

//=======
// testCases := []struct {
// opts *config.KanikoOptions
// retrieve bool
// }{
// {
// opts: &config.KanikoOptions{Cache: true},
// },
// {
// opts: &config.KanikoOptions{Cache: true},
// retrieve: true,
// },
// {
// opts: &config.KanikoOptions{Cache: false},
// },
// {
// opts: &config.KanikoOptions{Cache: false},
// retrieve: true,
// },
// }
// for i, tc := range testCases {
// t.Run(fmt.Sprintf("Case %d", i), func(t *testing.T) {
// file, err := ioutil.TempFile("", "foo")
// if err != nil {
// t.Error(err)
// }

// cf := &v1.ConfigFile{}
// snap := fakeSnapShotter{file: file.Name()}
// lc := fakeLayerCache{retrieve: tc.retrieve}
// sb := &stageBuilder{opts: tc.opts, cf: cf, snapshotter: snap, layerCache: lc, pushCache: fakeCachePush}

// command := MockDockerCommand{
// contextFiles: []string{file.Name()},
// cacheCommand: MockCachedDockerCommand{
// contextFiles: []string{file.Name()},
// },
// }
// sb.cmds = []commands.DockerCommand{command}
// err = sb.build()
// if err != nil {
// t.Errorf("Expected error to be nil but was %v", err)
// }
// })
// }
//}
//>>>>>>> Add unit tests for stagebuilder build and optimize
5 changes: 3 additions & 2 deletions pkg/executor/composite_cache.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ package executor

import (
"crypto/sha256"
"fmt"
"os"
"path/filepath"
"strings"
Expand Down Expand Up @@ -75,7 +76,7 @@ func (s *CompositeCache) AddPath(p string) error {
return err
}

s.keys = append(s.keys, string(sha.Sum(nil)))
s.keys = append(s.keys, fmt.Sprintf("%x", sha.Sum(nil)))
return nil
}

Expand All @@ -98,5 +99,5 @@ func HashDir(p string) (string, error) {
return "", err
}

return string(sha.Sum(nil)), nil
return fmt.Sprintf("%x", sha.Sum(nil)), nil
}

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