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feat: cache SHA3-384 entries #298

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35098a8
feat: cache SHA3-384 entries
upils May 22, 2026
34eee2a
ci: retry
upils May 26, 2026
65aa183
style: rename SHA3_384
upils Jun 1, 2026
013211f
test: cover Expire method
upils Jun 1, 2026
7b0eb14
fix: improve error message
upils Jun 2, 2026
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7 changes: 4 additions & 3 deletions internal/archive/archive.go
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Original file line number Diff line number Diff line change
Expand Up @@ -374,7 +374,8 @@ func (index *ubuntuIndex) distPath(suffix string) string {
}

func (index *ubuntuIndex) fetch(path, digest string, flags fetchFlags) (io.ReadSeekCloser, error) {
reader, err := index.archive.cache.Open(digest)
const algo = cache.SHA256
reader, err := index.archive.cache.Open(algo, digest)
if err == nil {
return reader, nil
} else if err != cache.MissErr {
Expand Down Expand Up @@ -425,7 +426,7 @@ func (index *ubuntuIndex) fetch(path, digest string, flags fetchFlags) (io.ReadS
body = reader
}

writer := index.archive.cache.Create(digest)
writer := index.archive.cache.Create(algo, digest)
defer writer.Close()

_, err = io.Copy(writer, body)
Expand All @@ -436,7 +437,7 @@ func (index *ubuntuIndex) fetch(path, digest string, flags fetchFlags) (io.ReadS
return nil, fmt.Errorf("cannot fetch from archive: %v", err)
}

return index.archive.cache.Open(writer.Digest())
return index.archive.cache.Open(algo, writer.Digest())
}

func sectionPackageInfo(section control.Section) *PackageInfo {
Expand Down
83 changes: 57 additions & 26 deletions internal/cache/cache.go
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@ import (
"os"
"path/filepath"
"time"

"golang.org/x/crypto/sha3"
)

func DefaultDir(suffix string) string {
Expand Down Expand Up @@ -89,41 +91,64 @@ func (cw *Writer) Digest() string {
return cw.digest
}

const digestKind = "sha256"
// hashAlgo identifies a supported hash algorithm.
type hashAlgo string

const (
SHA256 hashAlgo = "sha256"
SHA3_384 hashAlgo = "sha3-384"
)
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var hashAlgos = []hashAlgo{SHA256, SHA3_384}

func newHash(algo hashAlgo) (hash.Hash, error) {
switch algo {
case SHA256:
return sha256.New(), nil
case SHA3_384:
return sha3.New384(), nil
default:
return nil, fmt.Errorf("unsupported hash algorithm: %q", algo)
}
}

var MissErr = fmt.Errorf("not cached")

func (c *Cache) filePath(digest string) string {
return filepath.Join(c.Dir, digestKind, digest)
func (c *Cache) filePath(algo hashAlgo, digest string) string {
return filepath.Join(c.Dir, string(algo), digest)
}
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upils marked this conversation as resolved.

func (c *Cache) Create(digest string) *Writer {
func (c *Cache) Create(algo hashAlgo, digest string) *Writer {
if c.Dir == "" {
return &Writer{err: fmt.Errorf("internal error: cache directory is unset")}
}
err := os.MkdirAll(filepath.Join(c.Dir, digestKind), 0755)
h, err := newHash(algo)
if err != nil {
return &Writer{err: fmt.Errorf("internal error: %v", err)}
}
err = os.MkdirAll(filepath.Join(c.Dir, string(algo)), 0755)
if err != nil {
return &Writer{err: fmt.Errorf("cannot create cache directory: %v", err)}
}
var file *os.File
if digest == "" {
file, err = os.CreateTemp(c.filePath(""), "tmp.*")
file, err = os.CreateTemp(filepath.Join(c.Dir, string(algo)), "tmp.*")
} else {
file, err = os.Create(c.filePath(digest + ".tmp"))
file, err = os.Create(c.filePath(algo, digest+".tmp"))
}
if err != nil {
return &Writer{err: fmt.Errorf("cannot create cache file: %v", err)}
}
return &Writer{
dir: c.Dir,
digest: digest,
hash: sha256.New(),
hash: h,
file: file,
}
}

func (c *Cache) Write(digest string, data []byte) error {
f := c.Create(digest)
func (c *Cache) Write(algo hashAlgo, digest string, data []byte) error {
f := c.Create(algo, digest)
_, err1 := f.Write(data)
err2 := f.Close()
if err1 != nil {
Expand All @@ -132,11 +157,11 @@ func (c *Cache) Write(digest string, data []byte) error {
return err2
}

func (c *Cache) Open(digest string) (io.ReadSeekCloser, error) {
func (c *Cache) Open(algo hashAlgo, digest string) (io.ReadSeekCloser, error) {
if c.Dir == "" || digest == "" {
return nil, MissErr
}
filePath := c.filePath(digest)
filePath := c.filePath(algo, digest)
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upils marked this conversation as resolved.
file, err := os.Open(filePath)
if os.IsNotExist(err) {
return nil, MissErr
Expand All @@ -151,8 +176,8 @@ func (c *Cache) Open(digest string) (io.ReadSeekCloser, error) {
return file, nil
}

func (c *Cache) Read(digest string) ([]byte, error) {
file, err := c.Open(digest)
func (c *Cache) Read(algo hashAlgo, digest string) ([]byte, error) {
file, err := c.Open(algo, digest)
if err != nil {
return nil, err
}
Expand All @@ -165,22 +190,28 @@ func (c *Cache) Read(digest string) ([]byte, error) {
}

func (c *Cache) Expire(timeout time.Duration) error {
entries, err := os.ReadDir(filepath.Join(c.Dir, digestKind))
if err != nil {
return fmt.Errorf("cannot list cache directory: %v", err)
}
expired := time.Now().Add(-timeout)
for _, entry := range entries {
finfo, err := entry.Info()
if err != nil {
return err
}
if finfo.ModTime().After(expired) {
for _, algo := range hashAlgos {
algoDir := filepath.Join(c.Dir, string(algo))
entries, err := os.ReadDir(algoDir)
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if os.IsNotExist(err) {
continue
}
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err = os.Remove(filepath.Join(c.Dir, digestKind, finfo.Name()))
if err != nil {
return fmt.Errorf("cannot expire cache entry: %v", err)
return fmt.Errorf("cannot list cache directory: %v", err)
}
for _, entry := range entries {
finfo, err := entry.Info()
if err != nil {
return err
}
if finfo.ModTime().After(expired) {
continue
}
err = os.Remove(filepath.Join(algoDir, finfo.Name()))
if err != nil {
return fmt.Errorf("cannot expire cache entry: %v", err)
}
}
}
return nil
Expand Down
139 changes: 121 additions & 18 deletions internal/cache/cache_test.go
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Original file line number Diff line number Diff line change
@@ -1,14 +1,14 @@
package cache_test

import (
. "gopkg.in/check.v1"

"io"
"os"
"path/filepath"
"strings"
"time"

. "gopkg.in/check.v1"

"github.com/canonical/chisel/internal/cache"
)

Expand Down Expand Up @@ -45,11 +45,11 @@ func (s *S) TestDefaultDir(c *C) {
func (s *S) TestCacheEmpty(c *C) {
cc := cache.Cache{c.MkDir()}

_, err := cc.Open(data1Digest)
_, err := cc.Open(cache.SHA256, data1Digest)
c.Assert(err, Equals, cache.MissErr)
_, err = cc.Read(data1Digest)
_, err = cc.Read(cache.SHA256, data1Digest)
c.Assert(err, Equals, cache.MissErr)
_, err = cc.Read("")
_, err = cc.Read(cache.SHA256, "")
c.Assert(err, Equals, cache.MissErr)
}

Expand All @@ -60,21 +60,21 @@ func (s *S) TestCacheReadWrite(c *C) {
data2Path := filepath.Join(cc.Dir, "sha256", data2Digest)
data3Path := filepath.Join(cc.Dir, "sha256", data3Digest)

err := cc.Write(data1Digest, []byte("data1"))
err := cc.Write(cache.SHA256, data1Digest, []byte("data1"))
c.Assert(err, IsNil)
data1, err := cc.Read(data1Digest)
data1, err := cc.Read(cache.SHA256, data1Digest)
c.Assert(err, IsNil)
c.Assert(string(data1), Equals, "data1")

err = cc.Write("", []byte("data2"))
err = cc.Write(cache.SHA256, "", []byte("data2"))
c.Assert(err, IsNil)
data2, err := cc.Read(data2Digest)
data2, err := cc.Read(cache.SHA256, data2Digest)
c.Assert(err, IsNil)
c.Assert(string(data2), Equals, "data2")

_, err = cc.Read(data3Digest)
_, err = cc.Read(cache.SHA256, data3Digest)
c.Assert(err, Equals, cache.MissErr)
_, err = cc.Read("")
_, err = cc.Read(cache.SHA256, "")
c.Assert(err, Equals, cache.MissErr)

_, err = os.Stat(data1Path)
Expand All @@ -98,7 +98,7 @@ func (s *S) TestCacheReadWrite(c *C) {
func (s *S) TestCacheCreate(c *C) {
cc := cache.Cache{Dir: c.MkDir()}

w := cc.Create("")
w := cc.Create(cache.SHA256, "")

c.Assert(w.Digest(), Equals, "")

Expand All @@ -113,15 +113,15 @@ func (s *S) TestCacheCreate(c *C) {

c.Assert(w.Digest(), Equals, data1Digest)

data1, err := cc.Read(data1Digest)
data1, err := cc.Read(cache.SHA256, data1Digest)
c.Assert(err, IsNil)
c.Assert(string(data1), Equals, "data1")
}

func (s *S) TestCacheWrongDigest(c *C) {
cc := cache.Cache{Dir: c.MkDir()}

w := cc.Create(data1Digest)
w := cc.Create(cache.SHA256, data1Digest)

c.Assert(w.Digest(), Equals, data1Digest)

Expand All @@ -130,19 +130,19 @@ func (s *S) TestCacheWrongDigest(c *C) {
c.Assert(err, IsNil)
c.Assert(errClose, ErrorMatches, "expected digest "+data1Digest+", got "+data2Digest)

_, err = cc.Read(data1Digest)
_, err = cc.Read(cache.SHA256, data1Digest)
c.Assert(err, Equals, cache.MissErr)
_, err = cc.Read(data2Digest)
_, err = cc.Read(cache.SHA256, data2Digest)
c.Assert(err, Equals, cache.MissErr)
}

func (s *S) TestCacheOpen(c *C) {
cc := cache.Cache{Dir: c.MkDir()}

err := cc.Write(data1Digest, []byte("data1"))
err := cc.Write(cache.SHA256, data1Digest, []byte("data1"))
c.Assert(err, IsNil)

f, err := cc.Open(data1Digest)
f, err := cc.Open(cache.SHA256, data1Digest)
c.Assert(err, IsNil)
data1, err := io.ReadAll(f)
closeErr := f.Close()
Expand All @@ -151,3 +151,106 @@ func (s *S) TestCacheOpen(c *C) {

c.Assert(string(data1), Equals, "data1")
}

func (s *S) TestCacheSHA3384(c *C) {
cc := cache.Cache{Dir: c.MkDir()}

w := cc.Create(cache.SHA3_384, "")
_, err := w.Write([]byte("data1"))
c.Assert(err, IsNil)
err = w.Close()
c.Assert(err, IsNil)
sha3Digest := w.Digest()

c.Assert(sha3Digest, Not(Equals), data1Digest)

data, err := cc.Read(cache.SHA3_384, sha3Digest)
c.Assert(err, IsNil)
c.Assert(string(data), Equals, "data1")

// SHA3-384 entry must not be visible under SHA-256.
_, err = cc.Open(cache.SHA256, sha3Digest)
c.Assert(err, Equals, cache.MissErr)

// SHA-256 entry must not be visible under SHA3-384.
err = cc.Write(cache.SHA256, data1Digest, []byte("data1"))
c.Assert(err, IsNil)
_, err = cc.Open(cache.SHA3_384, data1Digest)
c.Assert(err, Equals, cache.MissErr)
}

func (s *S) TestCacheExpireBothAlgorithms(c *C) {
cc := cache.Cache{Dir: c.MkDir()}

// Write entries under both algorithms.
err := cc.Write(cache.SHA256, data1Digest, []byte("data1"))
c.Assert(err, IsNil)
err = cc.Write(cache.SHA256, data2Digest, []byte("data2"))
c.Assert(err, IsNil)

w := cc.Create(cache.SHA3_384, "")
_, err = w.Write([]byte("sha3data1"))
c.Assert(err, IsNil)
err = w.Close()
c.Assert(err, IsNil)
sha3Digest1 := w.Digest()

w = cc.Create(cache.SHA3_384, "")
_, err = w.Write([]byte("sha3data2"))
c.Assert(err, IsNil)
err = w.Close()
c.Assert(err, IsNil)
sha3Digest2 := w.Digest()

sha256Expired := filepath.Join(cc.Dir, "sha256", data1Digest)
sha256Fresh := filepath.Join(cc.Dir, "sha256", data2Digest)
sha3Expired := filepath.Join(cc.Dir, "sha3-384", sha3Digest1)
sha3Fresh := filepath.Join(cc.Dir, "sha3-384", sha3Digest2)

// Mark one entry per algorithm as expired.
now := time.Now()
expiredTime := now.Add(-2 * time.Hour)
err = os.Chtimes(sha256Expired, now, expiredTime)
c.Assert(err, IsNil)
err = os.Chtimes(sha3Expired, now, expiredTime)
c.Assert(err, IsNil)

err = cc.Expire(time.Hour)
c.Assert(err, IsNil)

// Expired entries must be removed from both algorithm directories.
_, err = os.Stat(sha256Expired)
c.Assert(os.IsNotExist(err), Equals, true)
_, err = os.Stat(sha3Expired)
c.Assert(os.IsNotExist(err), Equals, true)

// Fresh entries must remain in both algorithm directories.
_, err = os.Stat(sha256Fresh)
c.Assert(err, IsNil)
_, err = os.Stat(sha3Fresh)
c.Assert(err, IsNil)
}

func (s *S) TestCacheExpireMissingAlgoDir(c *C) {
cc := cache.Cache{Dir: c.MkDir()}

// Only write under SHA-256; the sha3-384 directory won't exist.
err := cc.Write(cache.SHA256, data1Digest, []byte("data1"))
c.Assert(err, IsNil)

// Expire should succeed despite the missing sha3-384 directory.
err = cc.Expire(time.Hour)
c.Assert(err, IsNil)

// The fresh SHA-256 entry must still be present.
_, err = os.Stat(filepath.Join(cc.Dir, "sha256", data1Digest))
c.Assert(err, IsNil)
}

func (s *S) TestCacheExpireNoAlgoDirs(c *C) {
cc := cache.Cache{Dir: c.MkDir()}

// No algorithm directories exist at all.
err := cc.Expire(time.Hour)
c.Assert(err, IsNil)
}