From b7337625759bd1c6ba4601b785ea40775610e314 Mon Sep 17 00:00:00 2001
From: Siyuan Liu <liusy182@gmail.com>
Date: Tue, 26 May 2020 23:16:07 -0400
Subject: [PATCH] provide and implement a new cache provider (#14496)

* provide and implement a new cache provider

* make interface more flexible

* let Connect and Close return error

Co-authored-by: mattermod <mattermod@users.noreply.github.com>
---
 services/cache2/provider.go      | 51 ++++++++++++++++++++++
 services/cache2/provider_test.go | 72 ++++++++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 services/cache2/provider.go
 create mode 100644 services/cache2/provider_test.go

diff --git a/services/cache2/provider.go b/services/cache2/provider.go
new file mode 100644
index 0000000000..284c43993e
--- /dev/null
+++ b/services/cache2/provider.go
@@ -0,0 +1,51 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package cache2
+
+import "time"
+
+// CacheOptions contains options for initializaing a cache
+type CacheOptions struct {
+	Size                   int
+	DefaultExpiry          time.Duration
+	Name                   string
+	InvalidateClusterEvent string
+}
+
+// Provider is a provider for Cache
+type Provider interface {
+	// NewCache creates a new cache with given options.
+	NewCache(opts *CacheOptions) Cache
+	// Connect opens a new connection to the cache using specific provider parameters.
+	Connect() error
+	// Close releases any resources used by the cache provider.
+	Close() error
+}
+
+type cacheProvider struct {
+}
+
+// NewProvider creates a new CacheProvider
+func NewProvider() Provider {
+	return &cacheProvider{}
+}
+
+// NewCache creates a new cache with given opts
+func (c *cacheProvider) NewCache(opts *CacheOptions) Cache {
+	return NewLRU(&LRUOptions{
+		Size:                   opts.Size,
+		DefaultExpiry:          opts.DefaultExpiry,
+		InvalidateClusterEvent: opts.InvalidateClusterEvent,
+	})
+}
+
+// Connect opens a new connection to the cache using specific provider parameters.
+func (c *cacheProvider) Connect() error {
+	return nil
+}
+
+// Close releases any resources used by the cache provider.
+func (c *cacheProvider) Close() error {
+	return nil
+}
diff --git a/services/cache2/provider_test.go b/services/cache2/provider_test.go
new file mode 100644
index 0000000000..5a22d3af00
--- /dev/null
+++ b/services/cache2/provider_test.go
@@ -0,0 +1,72 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package cache2
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewCache(t *testing.T) {
+	t.Run("with only size option given", func(t *testing.T) {
+		p := NewProvider()
+
+		size := 1
+		c := p.NewCache(&CacheOptions{
+			Size: size,
+		})
+
+		err := c.Set("key1", "val1")
+		require.Nil(t, err)
+		err = c.Set("key2", "val2")
+		require.Nil(t, err)
+		l, err := c.Len()
+		require.Nil(t, err)
+		require.Equal(t, size, l)
+	})
+
+	t.Run("with all options specified", func(t *testing.T) {
+		p := NewProvider()
+
+		size := 1
+		expiry := 1 * time.Second
+		event := "clusterEvent"
+		c := p.NewCache(&CacheOptions{
+			Size:                   size,
+			Name:                   "name",
+			DefaultExpiry:          expiry,
+			InvalidateClusterEvent: event,
+		})
+
+		require.Equal(t, event, c.GetInvalidateClusterEvent())
+
+		err := c.SetWithDefaultExpiry("key1", "val1")
+		require.Nil(t, err)
+		err = c.SetWithDefaultExpiry("key2", "val2")
+		require.Nil(t, err)
+		l, err := c.Len()
+		require.Nil(t, err)
+		require.Equal(t, size, l)
+
+		time.Sleep(expiry + 1*time.Second)
+
+		var v string
+		err = c.Get("key1", &v)
+		require.Equal(t, ErrKeyNotFound, err)
+		err = c.Get("key2", &v)
+		require.Equal(t, ErrKeyNotFound, err)
+	})
+}
+
+func TestConnectClose(t *testing.T) {
+	p := NewProvider()
+
+	err := p.Connect()
+	require.Nil(t, err)
+
+	err = p.Close()
+	require.Nil(t, err)
+}