Files
kopia/fs/cachefs/cache_test.go
2025-10-23 19:45:29 -07:00

299 lines
7.6 KiB
Go

package cachefs
import (
"context"
"fmt"
"maps"
"path/filepath"
"reflect"
"runtime"
"sync"
"sync/atomic"
"testing"
"time"
"github.com/pkg/errors"
"github.com/kopia/kopia/fs"
"github.com/kopia/kopia/internal/testlogging"
)
const expirationTime = 10 * time.Hour
type cacheSource struct {
data map[string][]fs.Entry
callCounter map[string]int
}
func identityWrapper(e fs.Entry) fs.Entry {
return e
}
func (cs *cacheSource) get(id string) func(ctx context.Context) ([]fs.Entry, error) {
return func(context.Context) ([]fs.Entry, error) {
cs.callCounter[id]++
d, ok := cs.data[id]
if !ok {
return nil, errors.New("no such id")
}
return d, nil
}
}
func (cs *cacheSource) setEntryCount(id string, cnt int) {
var fakeEntries []fs.Entry
var fakeEntry fs.Entry
for range cnt {
fakeEntries = append(fakeEntries, fakeEntry)
}
cs.data[id] = fakeEntries
cs.callCounter[id] = 0
}
func newCacheSource() *cacheSource {
return &cacheSource{
data: make(map[string][]fs.Entry),
callCounter: make(map[string]int),
}
}
type cacheVerifier struct {
cache *Cache
cacheSource *cacheSource
lastCallCounter map[string]int
}
func (cv *cacheVerifier) verifyCacheMiss(t *testing.T, id string) {
t.Helper()
actual := cv.cacheSource.callCounter[id]
expected := cv.lastCallCounter[id] + 1
if actual != expected {
t.Errorf(errorPrefix()+"invalid call counter for %v, got %v, expected %v", id, actual, expected)
}
cv.reset()
}
func (cv *cacheVerifier) verifyCacheHit(t *testing.T, id string) {
t.Helper()
if !reflect.DeepEqual(cv.lastCallCounter, cv.cacheSource.callCounter) {
t.Errorf(errorPrefix()+" unexpected call counters for %v, got %v, expected %v", id, cv.cacheSource.callCounter, cv.lastCallCounter)
}
cv.reset()
}
func (cv *cacheVerifier) verifyCacheOrdering(t *testing.T, expectedOrdering ...string) {
t.Helper()
var (
actualOrdering []string
totalDirectoryEntries, totalDirectories int
)
for e := cv.cache.head; e != nil; e = e.next {
actualOrdering = append(actualOrdering, e.id)
totalDirectoryEntries += len(e.entries)
totalDirectories++
}
if cv.cache.totalDirectoryEntries != totalDirectoryEntries {
t.Errorf("invalid totalDirectoryEntries: %v, expected %v", cv.cache.totalDirectoryEntries, totalDirectoryEntries)
}
if len(cv.cache.data) != totalDirectories {
t.Errorf("invalid total directories: %v, expected %v", len(cv.cache.data), totalDirectories)
}
if !reflect.DeepEqual(actualOrdering, expectedOrdering) {
t.Errorf(errorPrefix()+"unexpected ordering: %v, expected: %v", actualOrdering, expectedOrdering)
}
if totalDirectories > cv.cache.maxDirectories {
t.Errorf(errorPrefix()+"total directories exceeds limit: %v, expected %v", totalDirectories, cv.cache.maxDirectories)
}
if totalDirectoryEntries > cv.cache.maxDirectoryEntries {
t.Errorf(errorPrefix()+"total directory entries exceeds limit: %v, expected %v", totalDirectoryEntries, cv.cache.maxDirectoryEntries)
}
}
func errorPrefix() string {
if _, fn, line, ok := runtime.Caller(2); ok {
return fmt.Sprintf("called from %v:%v: ", filepath.Base(fn), line)
}
return ""
}
func (cv *cacheVerifier) reset() {
cv.lastCallCounter = maps.Clone(cv.cacheSource.callCounter)
}
type lockState struct {
l sync.Locker
locked atomic.Int32
}
// +checklocksacquire:ls.l
func (ls *lockState) Lock() {
ls.l.Lock()
ls.locked.Add(1)
}
// +checklocksrelease:ls.l
func (ls *lockState) Unlock() {
ls.locked.Add(-1)
ls.l.Unlock()
}
func (ls *lockState) Unlocked() bool {
return ls.locked.Load() == 0
}
func TestCache(t *testing.T) {
ctx := testlogging.Context(t)
c := NewCache(&Options{
MaxCachedDirectories: 4,
MaxCachedEntries: 100,
})
if len(c.data) != 0 || c.totalDirectoryEntries != 0 || c.head != nil || c.tail != nil {
t.Errorf("invalid initial state: %v %v %v %v", c.data, c.totalDirectoryEntries, c.head, c.tail)
}
cs := newCacheSource()
cv := cacheVerifier{cacheSource: cs, cache: c}
id1 := "1"
id2 := "2"
id3 := "3"
id4 := "4"
id5 := "5"
id6 := "6"
id7 := "7"
cs.setEntryCount(id1, 3)
cs.setEntryCount(id2, 3)
cs.setEntryCount(id3, 3)
cs.setEntryCount(id4, 95)
cs.setEntryCount(id5, 70)
cs.setEntryCount(id6, 100)
cs.setEntryCount(id7, 101)
cv.verifyCacheOrdering(t)
// fetch id1
_, _ = c.getEntries(ctx, id1, expirationTime, cs.get(id1), identityWrapper)
cv.verifyCacheMiss(t, id1)
cv.verifyCacheOrdering(t, id1)
// fetch id1 again - cache hit, no change
_, _ = c.getEntries(ctx, id1, expirationTime, cs.get(id1), identityWrapper)
cv.verifyCacheHit(t, id1)
cv.verifyCacheOrdering(t, id1)
// fetch id2
_, _ = c.getEntries(ctx, id2, expirationTime, cs.get(id2), identityWrapper)
cv.verifyCacheMiss(t, id2)
cv.verifyCacheOrdering(t, id2, id1)
// fetch id1 again - cache hit, id1 moved to the top of the LRU list
_, _ = c.getEntries(ctx, id1, expirationTime, cs.get(id1), identityWrapper)
cv.verifyCacheHit(t, id1)
cv.verifyCacheOrdering(t, id1, id2)
// fetch id2 again
_, _ = c.getEntries(ctx, id2, expirationTime, cs.get(id2), identityWrapper)
cv.verifyCacheHit(t, id2)
cv.verifyCacheOrdering(t, id2, id1)
// fetch id3
_, _ = c.getEntries(ctx, id3, expirationTime, cs.get(id3), identityWrapper)
cv.verifyCacheMiss(t, id3)
cv.verifyCacheOrdering(t, id3, id2, id1)
// fetch id4
_, _ = c.getEntries(ctx, id4, expirationTime, cs.get(id4), identityWrapper)
cv.verifyCacheMiss(t, id4)
cv.verifyCacheOrdering(t, id4, id3)
// fetch id1 again
_, _ = c.getEntries(ctx, id1, expirationTime, cs.get(id1), identityWrapper)
cv.verifyCacheMiss(t, id1)
cv.verifyCacheOrdering(t, id1, id4)
// fetch id5, it's a big one that expels all but one
_, _ = c.getEntries(ctx, id5, expirationTime, cs.get(id5), identityWrapper)
cv.verifyCacheMiss(t, id5)
cv.verifyCacheOrdering(t, id5, id1)
// fetch id6
_, _ = c.getEntries(ctx, id6, expirationTime, cs.get(id6), identityWrapper)
cv.verifyCacheMiss(t, id6)
cv.verifyCacheOrdering(t, id6)
// fetch id7
_, _ = c.getEntries(ctx, id7, expirationTime, cs.get(id7), identityWrapper)
cv.verifyCacheMiss(t, id7)
cv.verifyCacheOrdering(t, id6)
}
// Simple test for getEntries() locking/unlocking. Related to PRs #130 and #132.
func TestCacheGetEntriesLocking(t *testing.T) {
ctx := testlogging.Context(t)
c := NewCache(&Options{
MaxCachedDirectories: 4,
MaxCachedEntries: 100,
})
lock := &lockState{l: c.mu}
c.mu = lock // allow checking the lock state below
if len(c.data) != 0 || c.totalDirectoryEntries != 0 || c.head != nil || c.tail != nil {
t.Errorf("invalid initial state: %v %v %v %v", c.data, c.totalDirectoryEntries, c.head, c.tail)
}
cs := newCacheSource()
cv := cacheVerifier{cacheSource: cs, cache: c}
const id1 = "1"
cs.setEntryCount(id1, 1)
// fetch non-existing entry, the loader will return an error
actualEs, err := c.getEntries(ctx, id1, expirationTime, cs.get("foo"), identityWrapper)
if err == nil {
t.Fatal("Expected non-nil error when retrieving non-existing cache entry")
}
const expectedEsLength = 0
actualEsLength := len(actualEs)
if actualEsLength != expectedEsLength {
t.Fatal("Expected empty entries, got: ", actualEsLength)
}
// cache must be unlocked at this point: See #130
if !lock.Unlocked() {
t.Fatal("Cache is locked after returning from getEntries")
}
// fetch id1
_, _ = c.getEntries(ctx, id1, expirationTime, cs.get(id1), identityWrapper)
cv.verifyCacheMiss(t, id1)
// fetch id1 again - cache hit, no change
_, _ = c.getEntries(ctx, id1, expirationTime, cs.get(id1), identityWrapper)
cv.verifyCacheHit(t, id1)
// cache must be unlocked and there should be no double unlock: See #132
if !lock.Unlocked() {
t.Fatal("Cache is locked after returning from getEntries")
}
}