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nakabonnenakabonne
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Add a package that provides an interface to cache
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9 files changed

+374
-1
lines changed

9 files changed

+374
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lines changed

‎Makefile

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.PHONY: test
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test:
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go test -race -v -coverpkg=./... -covermode=atomic -coverprofile=coverage.txt ./...

‎NOTICE.txt

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pbgopy
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===============
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This product contains a modified part of pipe, distributed by pipe-cd:
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* License: https://github.com/pipe-cd/pipe/blob/master/LICENSE (Apache License v2.0)
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* Homepage: https://github.com/pipe-cd/pipe
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‎cache/cache.go

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// Copyright 2020 The PipeCD Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package cache provides an interface to temporarily
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// store content on a pbgopy server.
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package cache
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import (
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"errors"
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)
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var (
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ErrNotFound = errors.New("not found")
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)
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// Getter wraps a method to read from cache.
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type Getter interface {
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Get(key interface{}) (interface{}, error)
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}
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// Putter wraps a method to write to cache.
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type Putter interface {
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Put(key interface{}, value interface{}) error
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}
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// Deleter wraps a method to delete from cache.
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type Deleter interface {
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Delete(key interface{}) error
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}
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// Cache groups Getter, Putter and Deleter.
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type Cache interface {
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Getter
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Putter
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Deleter
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}
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type multiGetter struct {
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getters []Getter
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}
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// MultiGetter combines a lit of getters into a single getter.
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func MultiGetter(getters ...Getter) Getter {
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all := make([]Getter, 0, len(getters))
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for _, r := range getters {
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if mg, ok := r.(*multiGetter); ok {
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all = append(all, mg.getters...)
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} else {
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all = append(all, r)
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}
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}
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return &multiGetter{
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getters: all,
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}
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}
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func (mg *multiGetter) Get(key interface{}) (interface{}, error) {
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if len(mg.getters) == 0 {
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return nil, ErrNotFound
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}
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if len(mg.getters) == 1 {
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return mg.getters[0].Get(key)
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}
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var firstErr error
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for i := range mg.getters {
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e, err := mg.getters[i].Get(key)
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if firstErr == nil && err != nil {
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firstErr = err
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}
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if err == nil {
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return e, nil
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}
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}
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return nil, firstErr
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}

‎cache/cache_test.go

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// Copyright 2020 The PipeCD Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package cache
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import (
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"errors"
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"testing"
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"github.com/stretchr/testify/assert"
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)
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type getterFunc func(key interface{}) (interface{}, error)
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func (f getterFunc) Get(key interface{}) (interface{}, error) {
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return f(key)
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}
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func TestMultiGetter(t *testing.T) {
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value := "ok"
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err := errors.New("err")
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var calls int
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successGetter := getterFunc(func(key interface{}) (interface{}, error) {
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calls++
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return value, nil
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})
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failureGetter := getterFunc(func(key interface{}) (interface{}, error) {
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calls++
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return nil, err
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})
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testcases := []struct {
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name string
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getter Getter
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err error
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value interface{}
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calls int
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}{
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{
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getter: MultiGetter(successGetter),
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value: value,
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calls: 1,
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},
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{
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getter: MultiGetter(successGetter, successGetter),
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value: value,
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calls: 1,
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},
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{
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getter: MultiGetter(successGetter, failureGetter),
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value: value,
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calls: 1,
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},
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{
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getter: MultiGetter(failureGetter, successGetter),
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value: value,
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calls: 2,
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},
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{
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getter: MultiGetter(failureGetter, MultiGetter(failureGetter, successGetter)),
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value: value,
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calls: 3,
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},
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{
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getter: MultiGetter(failureGetter, failureGetter),
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err: err,
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calls: 2,
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},
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}
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for _, tc := range testcases {
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t.Run(tc.name, func(t *testing.T) {
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calls = 0
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value, err := tc.getter.Get("")
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assert.Equal(t, tc.err, err)
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assert.Equal(t, tc.value, value)
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assert.Equal(t, tc.calls, calls)
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})
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}
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}

‎cache/memorycache/cache.go

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// Copyright 2020 The PipeCD Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package memorycache
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import (
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"sync"
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"github.com/nakabonne/pbgopy/cache"
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)
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// Cache acts a simple cache that is safe for concurrent use
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// by multiple goroutines without additional locking or coordination.
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type Cache struct {
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values sync.Map
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}
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func NewCache() *Cache {
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return &Cache{}
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}
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func (c *Cache) Get(key interface{}) (interface{}, error) {
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item, ok := c.values.Load(key)
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if !ok {
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return nil, cache.ErrNotFound
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}
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return item, nil
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}
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func (c *Cache) Put(key interface{}, value interface{}) error {
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c.values.Store(key, value)
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return nil
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}
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func (c *Cache) Delete(key interface{}) error {
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c.values.Delete(key)
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return nil
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}

‎cache/memorycache/ttl_cache.go

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// Copyright 2020 The PipeCD Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package memorycache
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import (
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"context"
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"sync"
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"time"
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"github.com/nakabonne/pbgopy/cache"
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)
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type entry struct {
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value interface{}
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expiration time.Time
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}
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type TTLCache struct {
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entries sync.Map
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ttl time.Duration
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ctx context.Context
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}
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func NewTTLCache(ctx context.Context, ttl time.Duration, evictionInterval time.Duration) *TTLCache {
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c := &TTLCache{
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ttl: ttl,
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ctx: ctx,
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}
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if evictionInterval > 0 {
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go c.startEvicter(evictionInterval)
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}
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return c
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}
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func (c *TTLCache) startEvicter(interval time.Duration) {
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ticker := time.NewTicker(interval)
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for {
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select {
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case now := <-ticker.C:
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c.evictExpired(now)
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case <-c.ctx.Done():
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ticker.Stop()
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return
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}
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}
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}
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func (c *TTLCache) evictExpired(t time.Time) {
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c.entries.Range(func(key interface{}, value interface{}) bool {
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e := value.(*entry)
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if e.expiration.Before(t) {
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c.entries.Delete(key)
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}
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return true
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})
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}
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func (c *TTLCache) Get(key interface{}) (interface{}, error) {
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item, ok := c.entries.Load(key)
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if !ok {
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return nil, cache.ErrNotFound
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}
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return item.(*entry).value, nil
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}
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func (c *TTLCache) Put(key interface{}, value interface{}) error {
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e := &entry{
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value: value,
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expiration: time.Now().Add(c.ttl),
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}
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c.entries.Store(key, e)
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return nil
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}
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func (c *TTLCache) Delete(key interface{}) error {
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c.entries.Delete(key)
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return nil
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}

‎cache/memorycache/ttl_cache_test.go

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// Copyright 2020 The PipeCD Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
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package memorycache
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import (
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"context"
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"testing"
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"time"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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"github.com/nakabonne/pbgopy/cache"
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)
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func TestTTLCache(t *testing.T) {
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c := NewTTLCache(context.TODO(), 0, 5*time.Second)
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err := c.Put("key-1", "value-1")
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require.NoError(t, err)
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value, err := c.Get("key-1")
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require.NoError(t, err)
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assert.Equal(t, "value-1", value)
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c.evictExpired(time.Now())
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value, err = c.Get("key-1")
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assert.Equal(t, cache.ErrNotFound, err)
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assert.Equal(t, nil, value)
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}

‎go.mod

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33
go 1.15
44

5-
require github.com/spf13/cobra v1.1.1
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require (
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github.com/spf13/cobra v1.1.1
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github.com/stretchr/testify v1.3.0
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)

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