Deprecate and remove in-memory object caching (#5481)

in-memory caching cannot be cleanly implemented
without the access to GC which Go doesn't naturally
provide. At times we have seen that object caching
is more of an hindrance rather than a boon for
our use cases.

Removing it completely from our implementation
  related to #5160 and #5182
This commit is contained in:
Harshavardhana
2018-02-02 10:17:13 -08:00
committed by kannappanr
parent 1ebbc2ce88
commit 0c880bb852
15 changed files with 4 additions and 1022 deletions
-326
View File
@@ -1,326 +0,0 @@
/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package objcache
import (
"bytes"
"io"
"testing"
"time"
)
// TestObjectCache tests cases of object cache with expiry.
func TestObjExpiry(t *testing.T) {
// Non exhaustive list of all object cache behavior cases.
testCases := []struct {
expiry time.Duration
cacheSize uint64
err error
closeErr error
}{
{
expiry: 100 * time.Millisecond,
cacheSize: 1024,
err: ErrKeyNotFoundInCache,
closeErr: nil,
},
}
// Test case 1 validates running of GC.
testCase := testCases[0]
cache, err := New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
cache.OnEviction = func(key string) {}
w, err := cache.Create("test", 1)
if err != nil {
t.Errorf("Test case 1 expected to pass, failed instead %s", err)
}
// Write a byte.
w.Write([]byte("1"))
if err = w.Close(); err != nil {
t.Errorf("Test case 1 expected to pass, failed instead %s", err)
}
// Wait for 500 millisecond.
time.Sleep(500 * time.Millisecond)
// Setting objModTime to the beginning of golang's time.Time to avoid deletion of stale entry.
fakeObjModTime := time.Time{}
_, err = cache.Open("test", fakeObjModTime)
if err != testCase.err {
t.Errorf("Test case 1 expected %s, got instead %s", testCase.err, err)
}
}
// TestObjCache - tests various cases for object cache behavior.
func TestObjCache(t *testing.T) {
// Setting objModTime to the beginning of golang's time.Time to avoid deletion of stale entry.
fakeObjModTime := time.Time{}
// Non exhaustive list of all object cache behavior cases.
testCases := []struct {
expiry time.Duration
cacheSize uint64
err error
closeErr error
}{
// Validate if a key is not found in cache and Open fails.
{
expiry: NoExpiry,
cacheSize: 1024,
err: ErrKeyNotFoundInCache,
},
// Validate if cache indicates that it is full and Create fails.
{
expiry: NoExpiry,
cacheSize: 1,
err: ErrCacheFull,
},
// Validate if Create succeeds but Close fails to write to buffer.
{
expiry: NoExpiry,
cacheSize: 2,
closeErr: io.ErrShortBuffer,
},
// Validate that Create and Close succeed, making sure to update the cache.
{
expiry: NoExpiry,
cacheSize: 1024,
},
// Validate that Delete succeeds and Open fails with key not found in cache.
{
expiry: NoExpiry,
cacheSize: 1024,
err: ErrKeyNotFoundInCache,
},
// Validate OnEviction function is called upon entry delete.
{
expiry: NoExpiry,
cacheSize: 1024,
},
// Validate error excess data.
{
expiry: NoExpiry,
cacheSize: 5,
closeErr: ErrExcessData,
},
// Validate error excess data during write.
{
expiry: NoExpiry,
cacheSize: 2048,
err: ErrExcessData,
},
}
// Test 1 validating Open failure.
testCase := testCases[0]
cache, err := New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
_, err = cache.Open("test", fakeObjModTime)
if testCase.err != err {
t.Errorf("Test case 2 expected to pass, failed instead %s", err)
}
// Test 2 validating Create failure.
testCase = testCases[1]
cache, err = New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
_, err = cache.Create("test", 2)
if testCase.err != err {
t.Errorf("Test case 2 expected to pass, failed instead %s", err)
}
// Test 3 validating Create succeeds and returns a writer.
// Subsequently we Close() without writing any data, to receive
// `io.ErrShortBuffer`
testCase = testCases[2]
cache, err = New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
w, err := cache.Create("test", 1)
if testCase.err != err {
t.Errorf("Test case 3 expected to pass, failed instead %s", err)
}
if err = w.Close(); err != testCase.closeErr {
t.Errorf("Test case 3 expected to pass, failed instead %s", err)
}
// Test 4 validates Create and Close succeeds successfully caching
// the writes.
testCase = testCases[3]
cache, err = New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
w, err = cache.Create("test", 5)
if testCase.err != err {
t.Errorf("Test case 4 expected to pass, failed instead %s", err)
}
// Write '5' bytes.
w.Write([]byte("Hello"))
// Close to successfully save into cache.
if err = w.Close(); err != nil {
t.Errorf("Test case 4 expected to pass, failed instead %s", err)
}
r, err := cache.Open("test", fakeObjModTime)
if err != nil {
t.Errorf("Test case 4 expected to pass, failed instead %s", err)
}
// Reads everything stored for key "test".
cbytes := make([]byte, 5)
_, err = r.ReadAt(cbytes, 0)
if err != nil {
t.Errorf("Test case 4 expected to pass, failed instead %s", err)
}
// Validate if read bytes match.
if !bytes.Equal(cbytes, []byte("Hello")) {
t.Errorf("Test case 4 expected to pass. wanted \"Hello\", got %s", string(cbytes))
}
// Test 5 validates Delete succeeds and Open fails with err
testCase = testCases[4]
cache, err = New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
w, err = cache.Create("test", 5)
if err != nil {
t.Errorf("Test case 5 expected to pass, failed instead %s", err)
}
// Write '5' bytes.
w.Write([]byte("Hello"))
// Close to successfully save into cache.
if err = w.Close(); err != nil {
t.Errorf("Test case 5 expected to pass, failed instead %s", err)
}
// Delete the cache entry.
cache.Delete("test")
_, err = cache.Open("test", fakeObjModTime)
if testCase.err != err {
t.Errorf("Test case 5 expected to pass, failed instead %s", err)
}
// Test 6 validates OnEviction being called upon Delete is being invoked.
testCase = testCases[5]
cache, err = New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
w, err = cache.Create("test", 5)
if err != nil {
t.Errorf("Test case 6 expected to pass, failed instead %s", err)
}
// Write '5' bytes.
w.Write([]byte("Hello"))
// Close to successfully save into cache.
if err = w.Close(); err != nil {
t.Errorf("Test case 6 expected to pass, failed instead %s", err)
}
var deleteKey string
cache.OnEviction = func(key string) {
deleteKey = key
}
// Delete the cache entry.
cache.Delete("test")
if deleteKey != "test" {
t.Errorf("Test case 6 expected to pass, wanted \"test\", got %s", deleteKey)
}
// Test 7 validates rejecting requests when excess data is being saved.
testCase = testCases[6]
cache, err = New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
w, err = cache.Create("test1", 5)
if err != nil {
t.Errorf("Test case 7 expected to pass, failed instead %s", err)
}
// Write '5' bytes.
w.Write([]byte("Hello"))
// Close to successfully save into cache.
if err = w.Close(); err != nil {
t.Errorf("Test case 7 expected to pass, failed instead %s", err)
}
_, err = cache.Create("test2", 1)
if err != ErrCacheFull {
t.Errorf("Test case 7 expected to pass, failed instead %s", err)
}
// Test 8 validates rejecting Writes which write excess data.
testCase = testCases[7]
cache, err = New(testCase.cacheSize, testCase.expiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
w, err = cache.Create("test1", 5)
if err != nil {
t.Errorf("Test case 8 expected to pass, failed instead %s", err)
}
// Write '5' bytes.
n, err := w.Write([]byte("Hello"))
if err != nil {
t.Errorf("Test case 8 expected to pass, failed instead %s", err)
}
if n != 5 {
t.Errorf("Test case 8 expected 5 bytes written, instead found %d", n)
}
// Write '1' more byte, should return error.
n, err = w.Write([]byte("W"))
if n == 0 && err != testCase.err {
t.Errorf("Test case 8 expected to fail with ErrExcessData, but failed with %s instead", err)
}
}
// TestStateEntryPurge - tests if objCache purges stale entry and returns ErrKeyNotFoundInCache.
func TestStaleEntryPurge(t *testing.T) {
cache, err := New(1024, NoExpiry)
if err != nil {
t.Fatalf("Unable to create new objcache")
}
w, err := cache.Create("test", 5)
if err != nil {
t.Errorf("Test case expected to pass, failed instead %s", err)
}
// Write '5' bytes.
w.Write([]byte("Hello"))
// Close to successfully save into cache.
if err = w.Close(); err != nil {
t.Errorf("Test case expected to pass, failed instead %s", err)
}
_, err = cache.Open("test", time.Now().AddDate(0, 0, 1).UTC())
if err != ErrKeyNotFoundInCache {
t.Errorf("Test case expected to return ErrKeyNotFoundInCache, instead returned %s", err)
}
}