github.com/GoogleContainerTools/skaffold@v1.39.18/pkg/skaffold/tag/input_digest.go (about) 1 /* 2 Copyright 2019 The Skaffold 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 tag 18 19 import ( 20 "context" 21 "crypto/md5" 22 "crypto/sha256" 23 "encoding/hex" 24 "encoding/json" 25 "fmt" 26 "io" 27 "os" 28 "path/filepath" 29 "sort" 30 31 "github.com/GoogleContainerTools/skaffold/pkg/skaffold/docker" 32 "github.com/GoogleContainerTools/skaffold/pkg/skaffold/graph" 33 "github.com/GoogleContainerTools/skaffold/pkg/skaffold/output/log" 34 "github.com/GoogleContainerTools/skaffold/pkg/skaffold/schema/latest" 35 ) 36 37 type inputDigestTagger struct { 38 cfg docker.Config 39 cache graph.SourceDependenciesCache 40 } 41 42 func NewInputDigestTagger(cfg docker.Config, ag graph.ArtifactGraph) (Tagger, error) { 43 return &inputDigestTagger{ 44 cfg: cfg, 45 cache: graph.NewSourceDependenciesCache(cfg, nil, ag), 46 }, nil 47 } 48 49 func (t *inputDigestTagger) GenerateTag(ctx context.Context, image latest.Artifact) (string, error) { 50 var inputs []string 51 srcFiles, err := t.cache.TransitiveArtifactDependencies(ctx, &image) 52 if err != nil { 53 return "", err 54 } 55 56 // must sort as hashing is sensitive to the order in which files are processed 57 sort.Strings(srcFiles) 58 for _, d := range srcFiles { 59 h, err := fileHasher(d, image.Workspace) 60 if err != nil { 61 if os.IsNotExist(err) { 62 log.Entry(ctx).Tracef("skipping dependency %q for artifact cache calculation: %v", d, err) 63 continue // Ignore files that don't exist 64 } 65 66 return "", fmt.Errorf("getting hash for %q: %w", d, err) 67 } 68 inputs = append(inputs, h) 69 } 70 71 return encode(inputs) 72 } 73 74 func encode(inputs []string) (string, error) { 75 // get a key for the hashes 76 hasher := sha256.New() 77 enc := json.NewEncoder(hasher) 78 if err := enc.Encode(inputs); err != nil { 79 return "", err 80 } 81 return hex.EncodeToString(hasher.Sum(nil)), nil 82 } 83 84 // fileHasher hashes the contents and name of a file 85 func fileHasher(path string, workspacePath string) (string, error) { 86 h := md5.New() 87 fi, err := os.Lstat(path) 88 if err != nil { 89 return "", err 90 } 91 // Always try to use the file path relative to workspace when calculating hash. 92 // This will ensure we will always get the same hash independent of workspace location and hierarchy. 93 pathToHash, err := filepath.Rel(workspacePath, path) 94 if err != nil { 95 pathToHash = path 96 } 97 h.Write([]byte(pathToHash)) 98 99 if fi.Mode().IsRegular() { 100 f, err := os.Open(path) 101 if err != nil { 102 return "", err 103 } 104 defer f.Close() 105 if _, err := io.Copy(h, f); err != nil { 106 return "", err 107 } 108 } 109 return hex.EncodeToString(h.Sum(nil)), nil 110 }