cache/bug_cache.go 🔗
@@ -37,8 +37,6 @@ func (c *BugCache) Snapshot() *bug.Snapshot {
}
func (c *BugCache) Id() entity.Id {
- c.mu.RLock()
- defer c.mu.RUnlock()
return c.bug.Id()
}
Merge pull request #449 from MichaelMure/lru-cache
Michael Muré created
LRU CacheChange summary
cache/bug_cache.go | 2 -
cache/lru_id_cache.go | 56 ++++++++++++++++++++++++++++
cache/repo_cache.go | 24 ++++++++++--
cache/repo_cache_bug.go | 62 +++++++++++++++++++++++++++---
cache/repo_cache_test.go | 84 ++++++++++++++++++++++++++++++++++++-----
go.mod | 2
go.sum | 1
7 files changed, 206 insertions(+), 25 deletions(-)
Detailed changes
cache/lru_id_cache.go 🔗
@@ -0,0 +1,56 @@
+package cache
+
+import (
+ "math"
+
+ lru "github.com/hashicorp/golang-lru"
+
+ "github.com/MichaelMure/git-bug/entity"
+)
+
+type LRUIdCache struct {
+ parentCache *lru.Cache
+}
+
+func NewLRUIdCache() *LRUIdCache {
+ // we can ignore the error here as it would only fail if the size is negative.
+ cache, _ := lru.New(math.MaxInt32)
+
+ return &LRUIdCache{
+ cache,
+ }
+}
+
+func (c *LRUIdCache) Add(id entity.Id) bool {
+ return c.parentCache.Add(id, nil)
+}
+
+func (c *LRUIdCache) Contains(id entity.Id) bool {
+ return c.parentCache.Contains(id)
+}
+
+func (c *LRUIdCache) Get(id entity.Id) bool {
+ _, present := c.parentCache.Get(id)
+ return present
+}
+
+func (c *LRUIdCache) GetOldest() (entity.Id, bool) {
+ id, _, present := c.parentCache.GetOldest()
+ return id.(entity.Id), present
+}
+
+func (c *LRUIdCache) GetOldestToNewest() (ids []entity.Id) {
+ interfaceKeys := c.parentCache.Keys()
+ for _, id := range interfaceKeys {
+ ids = append(ids, id.(entity.Id))
+ }
+ return
+}
+
+func (c *LRUIdCache) Len() int {
+ return c.parentCache.Len()
+}
+
+func (c *LRUIdCache) Remove(id entity.Id) bool {
+ return c.parentCache.Remove(id)
+}
cache/repo_cache.go 🔗
@@ -21,6 +21,9 @@ import (
// 2: added cache for identities with a reference in the bug cache
const formatVersion = 2
+// The maximum number of bugs loaded in memory. After that, eviction will be done.
+const defaultMaxLoadedBugs = 1000
+
var _ repository.RepoCommon = &RepoCache{}
// RepoCache is a cache for a Repository. This cache has multiple functions:
@@ -44,11 +47,16 @@ type RepoCache struct {
// the name of the repository, as defined in the MultiRepoCache
name string
+ // maximum number of loaded bugs
+ maxLoadedBugs int
+
muBug sync.RWMutex
// excerpt of bugs data for all bugs
bugExcerpts map[entity.Id]*BugExcerpt
// bug loaded in memory
bugs map[entity.Id]*BugCache
+ // loadedBugs is an LRU cache that records which bugs the cache has loaded in
+ loadedBugs *LRUIdCache
muIdentity sync.RWMutex
// excerpt of identities data for all identities
@@ -66,10 +74,12 @@ func NewRepoCache(r repository.ClockedRepo) (*RepoCache, error) {
func NewNamedRepoCache(r repository.ClockedRepo, name string) (*RepoCache, error) {
c := &RepoCache{
- repo: r,
- name: name,
- bugs: make(map[entity.Id]*BugCache),
- identities: make(map[entity.Id]*IdentityCache),
+ repo: r,
+ name: name,
+ maxLoadedBugs: defaultMaxLoadedBugs,
+ bugs: make(map[entity.Id]*BugCache),
+ loadedBugs: NewLRUIdCache(),
+ identities: make(map[entity.Id]*IdentityCache),
}
err := c.lock()
@@ -91,6 +101,12 @@ func NewNamedRepoCache(r repository.ClockedRepo, name string) (*RepoCache, error
return c, c.write()
}
+// setCacheSize change the maximum number of loaded bugs
+func (c *RepoCache) setCacheSize(size int) {
+ c.maxLoadedBugs = size
+ c.evictIfNeeded()
+}
+
// load will try to read from the disk all the cache files
func (c *RepoCache) load() error {
err := c.loadBugCache()
cache/repo_cache_bug.go 🔗
@@ -3,6 +3,7 @@ package cache
import (
"bytes"
"encoding/gob"
+ "errors"
"fmt"
"os"
"path"
@@ -17,6 +18,8 @@ import (
const bugCacheFile = "bug-cache"
+var errBugNotInCache = errors.New("bug missing from cache")
+
func bugCacheFilePath(repo repository.Repo) string {
return path.Join(repo.GetPath(), "git-bug", bugCacheFile)
}
@@ -25,13 +28,18 @@ func bugCacheFilePath(repo repository.Repo) string {
// that is each time a bug is updated
func (c *RepoCache) bugUpdated(id entity.Id) error {
c.muBug.Lock()
-
b, ok := c.bugs[id]
if !ok {
c.muBug.Unlock()
- panic("missing bug in the cache")
- }
+ // if the bug is not loaded at this point, it means it was loaded before
+ // but got evicted. Which means we potentially have multiple copies in
+ // memory and thus concurrent write.
+ // Failing immediately here is the simple and safe solution to avoid
+ // complicated data loss.
+ return errBugNotInCache
+ }
+ c.loadedBugs.Get(id)
c.bugExcerpts[id] = NewBugExcerpt(b.bug, b.Snapshot())
c.muBug.Unlock()
@@ -109,22 +117,24 @@ func (c *RepoCache) ResolveBugExcerpt(id entity.Id) (*BugExcerpt, error) {
c.muBug.RLock()
defer c.muBug.RUnlock()
- e, ok := c.bugExcerpts[id]
+ excerpt, ok := c.bugExcerpts[id]
if !ok {
return nil, bug.ErrBugNotExist
}
- return e, nil
+ return excerpt, nil
}
// ResolveBug retrieve a bug matching the exact given id
func (c *RepoCache) ResolveBug(id entity.Id) (*BugCache, error) {
c.muBug.RLock()
cached, ok := c.bugs[id]
- c.muBug.RUnlock()
if ok {
+ c.loadedBugs.Get(id)
+ c.muBug.RUnlock()
return cached, nil
}
+ c.muBug.RUnlock()
b, err := bug.ReadLocalBug(c.repo, id)
if err != nil {
@@ -135,11 +145,39 @@ func (c *RepoCache) ResolveBug(id entity.Id) (*BugCache, error) {
c.muBug.Lock()
c.bugs[id] = cached
+ c.loadedBugs.Add(id)
c.muBug.Unlock()
+ c.evictIfNeeded()
+
return cached, nil
}
+// evictIfNeeded will evict a bug from the cache if needed
+// it also removes references of the bug from the bugs
+func (c *RepoCache) evictIfNeeded() {
+ c.muBug.Lock()
+ defer c.muBug.Unlock()
+ if c.loadedBugs.Len() <= c.maxLoadedBugs {
+ return
+ }
+
+ for _, id := range c.loadedBugs.GetOldestToNewest() {
+ b := c.bugs[id]
+ if b.NeedCommit() {
+ continue
+ }
+
+ b.mu.Lock()
+ c.loadedBugs.Remove(id)
+ delete(c.bugs, id)
+
+ if c.loadedBugs.Len() <= c.maxLoadedBugs {
+ return
+ }
+ }
+}
+
// ResolveBugExcerptPrefix retrieve a BugExcerpt matching an id prefix. It fails if multiple
// bugs match.
func (c *RepoCache) ResolveBugExcerptPrefix(prefix string) (*BugExcerpt, error) {
@@ -349,8 +387,11 @@ func (c *RepoCache) NewBugRaw(author *IdentityCache, unixTime int64, title strin
cached := NewBugCache(c, b)
c.bugs[b.Id()] = cached
+ c.loadedBugs.Add(b.Id())
c.muBug.Unlock()
+ c.evictIfNeeded()
+
// force the write of the excerpt
err = c.bugUpdated(b.Id())
if err != nil {
@@ -362,16 +403,23 @@ func (c *RepoCache) NewBugRaw(author *IdentityCache, unixTime int64, title strin
// RemoveBug removes a bug from the cache and repo given a bug id prefix
func (c *RepoCache) RemoveBug(prefix string) error {
- b, err := c.ResolveBugPrefix(prefix)
+ c.muBug.RLock()
+ b, err := c.ResolveBugPrefix(prefix)
if err != nil {
+ c.muBug.RUnlock()
return err
}
+ c.muBug.RUnlock()
+ c.muBug.Lock()
err = bug.RemoveBug(c.repo, b.Id())
delete(c.bugs, b.Id())
delete(c.bugExcerpts, b.Id())
+ c.loadedBugs.Remove(b.Id())
+
+ c.muBug.Unlock()
return c.writeBugCache()
}
cache/repo_cache_test.go 🔗
@@ -1,9 +1,7 @@
package cache
import (
- "fmt"
"testing"
- "time"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
@@ -85,7 +83,8 @@ func TestCache(t *testing.T) {
require.Empty(t, cache.identitiesExcerpts)
// Reload, only excerpt are loaded
- require.NoError(t, cache.load())
+ cache, err = NewRepoCache(repo)
+ require.NoError(t, err)
require.Empty(t, cache.bugs)
require.Empty(t, cache.identities)
require.Len(t, cache.bugExcerpts, 2)
@@ -177,17 +176,17 @@ func TestRemove(t *testing.T) {
repoCache, err := NewRepoCache(repo)
require.NoError(t, err)
- // generate a bunch of bugs
rene, err := repoCache.NewIdentity("René Descartes", "rene@descartes.fr")
require.NoError(t, err)
- for i := 0; i < 100; i++ {
- _, _, err := repoCache.NewBugRaw(rene, time.Now().Unix(), "title", fmt.Sprintf("message%v", i), nil, nil)
- require.NoError(t, err)
- }
+ err = repoCache.SetUserIdentity(rene)
+ require.NoError(t, err)
+
+ _, _, err = repoCache.NewBug("title", "message")
+ require.NoError(t, err)
// and one more for testing
- b1, _, err := repoCache.NewBugRaw(rene, time.Now().Unix(), "title", "message", nil, nil)
+ b1, _, err := repoCache.NewBug("title", "message")
require.NoError(t, err)
_, err = repoCache.Push("remoteA")
@@ -204,9 +203,72 @@ func TestRemove(t *testing.T) {
err = repoCache.RemoveBug(b1.Id().String())
require.NoError(t, err)
- assert.Equal(t, 100, len(repoCache.bugs))
- assert.Equal(t, 100, len(repoCache.bugExcerpts))
+ assert.Equal(t, 1, len(repoCache.bugs))
+ assert.Equal(t, 1, len(repoCache.bugExcerpts))
_, err = repoCache.ResolveBug(b1.Id())
assert.Error(t, bug.ErrBugNotExist, err)
}
+
+func TestCacheEviction(t *testing.T) {
+ repo := repository.CreateTestRepo(false)
+ repoCache, err := NewRepoCache(repo)
+ require.NoError(t, err)
+ repoCache.setCacheSize(2)
+
+ require.Equal(t, 2, repoCache.maxLoadedBugs)
+ require.Equal(t, 0, repoCache.loadedBugs.Len())
+ require.Equal(t, 0, len(repoCache.bugs))
+
+ // Generating some bugs
+ rene, err := repoCache.NewIdentity("René Descartes", "rene@descartes.fr")
+ require.NoError(t, err)
+ err = repoCache.SetUserIdentity(rene)
+ require.NoError(t, err)
+
+ bug1, _, err := repoCache.NewBug("title", "message")
+ require.NoError(t, err)
+
+ checkBugPresence(t, repoCache, bug1, true)
+ require.Equal(t, 1, repoCache.loadedBugs.Len())
+ require.Equal(t, 1, len(repoCache.bugs))
+
+ bug2, _, err := repoCache.NewBug("title", "message")
+ require.NoError(t, err)
+
+ checkBugPresence(t, repoCache, bug1, true)
+ checkBugPresence(t, repoCache, bug2, true)
+ require.Equal(t, 2, repoCache.loadedBugs.Len())
+ require.Equal(t, 2, len(repoCache.bugs))
+
+ // Number of bugs should not exceed max size of lruCache, oldest one should be evicted
+ bug3, _, err := repoCache.NewBug("title", "message")
+ require.NoError(t, err)
+
+ require.Equal(t, 2, repoCache.loadedBugs.Len())
+ require.Equal(t, 2, len(repoCache.bugs))
+ checkBugPresence(t, repoCache, bug1, false)
+ checkBugPresence(t, repoCache, bug2, true)
+ checkBugPresence(t, repoCache, bug3, true)
+
+ // Accessing bug should update position in lruCache and therefore it should not be evicted
+ repoCache.loadedBugs.Get(bug2.Id())
+ oldestId, _ := repoCache.loadedBugs.GetOldest()
+ require.Equal(t, bug3.Id(), oldestId)
+
+ checkBugPresence(t, repoCache, bug1, false)
+ checkBugPresence(t, repoCache, bug2, true)
+ checkBugPresence(t, repoCache, bug3, true)
+ require.Equal(t, 2, repoCache.loadedBugs.Len())
+ require.Equal(t, 2, len(repoCache.bugs))
+}
+
+func checkBugPresence(t *testing.T, cache *RepoCache, bug *BugCache, presence bool) {
+ id := bug.Id()
+ require.Equal(t, presence, cache.loadedBugs.Contains(id))
+ b, ok := cache.bugs[id]
+ require.Equal(t, presence, ok)
+ if ok {
+ require.Equal(t, bug, b)
+ }
+}
go.mod 🔗
@@ -13,7 +13,7 @@ require (
github.com/dustin/go-humanize v1.0.0
github.com/fatih/color v1.9.0
github.com/gorilla/mux v1.7.4
- github.com/hashicorp/golang-lru v0.5.4 // indirect
+ github.com/hashicorp/golang-lru v0.5.4
github.com/icrowley/fake v0.0.0-20180203215853-4178557ae428
github.com/mattn/go-isatty v0.0.12
github.com/phayes/freeport v0.0.0-20171002181615-b8543db493a5
go.sum 🔗
@@ -109,6 +109,7 @@ github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0/go.mod h1:8NvIoxWQoOIhqOTXgf
github.com/grpc-ecosystem/grpc-gateway v1.9.0/go.mod h1:vNeuVxBJEsws4ogUvrchl83t/GYV9WGTSLVdBhOQFDY=
github.com/hashicorp/go-cleanhttp v0.5.1 h1:dH3aiDG9Jvb5r5+bYHsikaOUIpcM0xvgMXVoDkXMzJM=
github.com/hashicorp/go-cleanhttp v0.5.1/go.mod h1:JpRdi6/HCYpAwUzNwuwqhbovhLtngrth3wmdIIUrZ80=
+github.com/hashicorp/go-hclog v0.9.2 h1:CG6TE5H9/JXsFWJCfoIVpKFIkFe6ysEuHirp4DxCsHI=
github.com/hashicorp/go-hclog v0.9.2/go.mod h1:5CU+agLiy3J7N7QjHK5d05KxGsuXiQLrjA0H7acj2lQ=
github.com/hashicorp/go-retryablehttp v0.6.4 h1:BbgctKO892xEyOXnGiaAwIoSq1QZ/SS4AhjoAh9DnfY=
github.com/hashicorp/go-retryablehttp v0.6.4/go.mod h1:vAew36LZh98gCBJNLH42IQ1ER/9wtLZZ8meHqQvEYWY=