Initial implementation (still has TODOs)

Signed-off-by: Natalie Arellano <narellano@vmware.com>

internal/config/config.go

@@ -23,6 +23,7 @@ type Config struct {
  LifecycleImage string `toml:"lifecycle-image,omitempty"`
  RegistryMirrors map[string]string `toml:"registry-mirrors,omitempty"`
  LayoutRepositoryDir string `toml:"layout-repo-dir,omitempty"`
+ VolumeKeys map[string]string `toml:"volume-keys,omitempty"` // TODO: move to own struct
 }
 
 type Registry struct {
@@ -58,6 +59,14 @@ func DefaultConfigPath() (string, error) {
  return filepath.Join(home, "config.toml"), nil
 }
 
+func DefaultVolumeKeysPath() (string, error) {
+ home, err := PackHome()
+ if err != nil {
+ return "", errors.Wrap(err, "getting pack home")
+ }
+ return filepath.Join(home, "volume-keys.toml"), nil
+}
+
 func PackHome() (string, error) {
  packHome := os.Getenv("PACK_HOME")
  if packHome == "" {

pkg/cache/volume_cache.go

@@ -2,16 +2,21 @@ package cache
 
 import (
  "context"
+ "crypto/rand"
  "crypto/sha256"
  "fmt"
+ "os"
  "strings"
 
  "github.com/docker/docker/client"
  "github.com/google/go-containerregistry/pkg/name"
 
+ "github.com/buildpacks/pack/internal/config"
  "github.com/buildpacks/pack/internal/paths"
 )
 
+const EnvVolumeKey = "PACK_VOLUME_KEY"
+
 type VolumeCache struct {
  docker DockerClient
  volume string
@@ -20,7 +25,11 @@ type VolumeCache struct {
 func NewVolumeCache(imageRef name.Reference, cacheType CacheInfo, suffix string, dockerClient DockerClient) *VolumeCache {
  var volumeName string
  if cacheType.Source == "" {
- sum := sha256.Sum256([]byte(imageRef.Name()))
+ volumeKey, err := getVolumeKey(imageRef)
+ if err != nil {
+ // TODO
+ }
+ sum := sha256.Sum256([]byte(imageRef.Name() + volumeKey)) // TODO: investigate if there are better ways to do this
  vol := paths.FilterReservedNames(fmt.Sprintf("%s-%x", sanitizedRef(imageRef), sum[:6]))
  volumeName = fmt.Sprintf("pack-cache-%s.%s", vol, suffix)
  } else {
@@ -33,6 +42,59 @@ func NewVolumeCache(imageRef name.Reference, cacheType CacheInfo, suffix string,
  }
 }
 
+func getVolumeKey(imageRef name.Reference) (string, error) {
+ var foundKey string
+
+ // first, look for key in env
+
+ foundKey = os.Getenv(EnvVolumeKey)
+ if foundKey != "" {
+ return foundKey, nil
+ }
+
+ // then, look for key in existing config
+
+ volumeKeysPath, err := config.DefaultVolumeKeysPath()
+ if err != nil {
+ return "", err
+ }
+ cfg, err := config.Read(volumeKeysPath)
+ if err != nil {
+ return "", err
+ }
+
+ foundKey = cfg.VolumeKeys[imageRef.Name()]
+ if foundKey != "" {
+ return foundKey, nil
+ }
+
+ // finally, create new key and store it in config
+
+ newKey := randString(20)
+ if cfg.VolumeKeys == nil {
+ cfg.VolumeKeys = make(map[string]string)
+ }
+ cfg.VolumeKeys[imageRef.Name()] = newKey
+ if err = config.Write(cfg, volumeKeysPath); err != nil {
+ return "", err
+ }
+
+ return newKey, nil
+}
+
+// Returns a string iwith lowercase a-z, of length n
+func randString(n int) string {
+ b := make([]byte, n)
+ _, err := rand.Read(b)
+ if err != nil {
+ panic(err)
+ }
+ for i := range b {
+ b[i] = 'a' + (b[i] % 26)
+ }
+ return string(b)
+}
+
 func (c *VolumeCache) Name() string {
  return c.volume
 }

pkg/cache/volume_cache_test.go

@@ -2,9 +2,12 @@ package cache_test
 
 import (
  "context"
+ "os"
+ "path/filepath"
  "strings"
  "testing"
 
+ "github.com/buildpacks/pack/internal/config"
  "github.com/buildpacks/pack/pkg/cache"
 
  "github.com/docker/docker/api/types/filters"
@@ -24,7 +27,7 @@ func TestVolumeCache(t *testing.T) {
  color.Disable(true)
  defer color.Disable(false)
 
- spec.Run(t, "VolumeCache", testCache, spec.Parallel(), spec.Report(report.Terminal{}))
+ spec.Run(t, "VolumeCache", testCache, spec.Sequential(), spec.Report(report.Terminal{}))
 }
 
 func testCache(t *testing.T, when spec.G, it spec.S) {
@@ -118,6 +121,72 @@ func testCache(t *testing.T, when spec.G, it spec.S) {
  h.AssertContains(t, subject.Name(), "fedora_httpd_version1.0")
  h.AssertTrue(t, names.RestrictedNamePattern.MatchString(subject.Name()))
  })
+
+ when("PACK_VOLUME_KEY", func() {
+ when("is set", func() {
+ it.After(func() {
+ h.AssertNil(t, os.Unsetenv("PACK_VOLUME_KEY"))
+ })
+
+ it("uses it to construct the volume name", func() {
+ ref, err := name.ParseReference("my/repo:some-tag", name.WeakValidation)
+ h.AssertNil(t, err)
+
+ nameFromNewKey := cache.NewVolumeCache(ref, cache.CacheInfo{}, "some-suffix", dockerClient) // sources a new key
+ h.AssertNil(t, os.Setenv("PACK_VOLUME_KEY", "some-volume-key"))
+ nameFromEnvKey := cache.NewVolumeCache(ref, cache.CacheInfo{}, "some-suffix", dockerClient) // sources key from env
+ h.AssertNotEq(t, nameFromNewKey.Name(), nameFromEnvKey.Name())
+ })
+ })
+
+ when("is unset", func() {
+ var tmpPackHome string
+
+ it.Before(func() {
+ var err error
+ tmpPackHome, err = os.MkdirTemp("", "")
+ h.AssertNil(t, err)
+ h.AssertNil(t, os.Setenv("PACK_HOME", tmpPackHome))
+ })
+
+ it.After(func() {
+ h.AssertNil(t, os.RemoveAll(tmpPackHome))
+ })
+
+ when("~/.pack/volume-keys.toml contains key for repo name", func() {
+ it("sources the key from ~/.pack/volume-keys.toml", func() {
+ ref, err := name.ParseReference("my/repo:some-tag", name.WeakValidation)
+ h.AssertNil(t, err)
+
+ nameFromNewKey := cache.NewVolumeCache(ref, cache.CacheInfo{}, "some-suffix", dockerClient) // sources a new key
+
+ cfgContents := `
+[volume-keys]
+"index.docker.io/my/repo:some-tag" = "SOME_VOLUME_KEY"
+`
+ h.AssertNil(t, os.WriteFile(filepath.Join(tmpPackHome, "volume-keys.toml"), []byte(cfgContents), 0755)) // overrides the key that was set
+
+ nameFromConfigKey := cache.NewVolumeCache(ref, cache.CacheInfo{}, "some-suffix", dockerClient) // sources key from config
+ h.AssertNotEq(t, nameFromNewKey.Name(), nameFromConfigKey.Name())
+ })
+ })
+
+ when("~/.pack/volume-keys.toml missing key for repo name", func() {
+ it("generates a new key and saves it to ~/.pack/volume-keys.toml", func() {
+ ref, err := name.ParseReference("my/repo:some-tag", name.WeakValidation)
+ h.AssertNil(t, err)
+
+ nameFromNewKey := cache.NewVolumeCache(ref, cache.CacheInfo{}, "some-suffix", dockerClient) // sources a new key
+ nameFromConfigKey := cache.NewVolumeCache(ref, cache.CacheInfo{}, "some-suffix", dockerClient) // sources same key from config
+ h.AssertEq(t, nameFromNewKey.Name(), nameFromConfigKey.Name())
+
+ cfg, err := config.Read(filepath.Join(tmpPackHome, "volume-keys.toml"))
+ h.AssertNil(t, err)
+ h.AssertNotNil(t, cfg.VolumeKeys["index.docker.io/my/repo:some-tag"])
+ })
+ })
+ })
+ })
  })
 
  when("volume cache name is not empty", func() {