From c73a53dbe32261a6fdc6f9045ceb664ce8d161f4 Mon Sep 17 00:00:00 2001
From: Dane Everitt <dane@daneeveritt.com>
Date: Sat, 22 Aug 2020 22:50:49 -0700
Subject: [PATCH] Replace cache with single int64

---
 server/filesystem.go | 20 ++++++++++++--------
 server/loader.go     |  2 --
 server/server.go     |  5 -----
 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/server/filesystem.go b/server/filesystem.go
index 9368293..ad0a452 100644
--- a/server/filesystem.go
+++ b/server/filesystem.go
@@ -40,8 +40,12 @@ func IsPathResolutionError(err error) bool {
 }
 
 type Filesystem struct {
-	Server      *Server
-	cacheDiskMu sync.Mutex
+	mu sync.RWMutex
+
+	lastLookupTime time.Time
+	diskUsage      int64
+
+	Server *Server
 }
 
 // Returns the root path that contains all of a server's data.
@@ -241,11 +245,11 @@ func (fs *Filesystem) getCachedDiskUsage() (int64, error) {
 	//
 	// This effectively the same speed as running this call in parallel since this cache will return
 	// instantly on the second call.
-	fs.cacheDiskMu.Lock()
-	defer fs.cacheDiskMu.Unlock()
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
 
-	if x, exists := fs.Server.cache.Get("disk_used"); exists {
-		return x.(int64), nil
+	if fs.lastLookupTime.After(time.Now().Add(time.Second * -60)) {
+		return fs.diskUsage, nil
 	}
 
 	// If there is no size its either because there is no data (in which case running this function
@@ -257,7 +261,8 @@ func (fs *Filesystem) getCachedDiskUsage() (int64, error) {
 	// Always cache the size, even if there is an error. We want to always return that value
 	// so that we don't cause an endless loop of determining the disk size if there is a temporary
 	// error encountered.
-	fs.Server.cache.Set("disk_used", size, time.Second*60)
+	fs.lastLookupTime = time.Now()
+	atomic.StoreInt64(&fs.diskUsage, size)
 
 	return size, err
 }
@@ -416,7 +421,6 @@ func (fs *Filesystem) unsafeStat(p string) (*Stat, error) {
 		}
 	}
 
-
 	st := &Stat{
 		Info:     s,
 		Mimetype: "inode/directory",
diff --git a/server/loader.go b/server/loader.go
index 92283ee..79b2cca 100644
--- a/server/loader.go
+++ b/server/loader.go
@@ -5,7 +5,6 @@ import (
 	"github.com/apex/log"
 	"github.com/creasty/defaults"
 	"github.com/gammazero/workerpool"
-	"github.com/patrickmn/go-cache"
 	"github.com/pkg/errors"
 	"github.com/pterodactyl/wings/api"
 	"github.com/pterodactyl/wings/environment"
@@ -98,7 +97,6 @@ func FromConfiguration(data *api.ServerConfigurationResponse) (*Server, error) {
 		return nil, err
 	}
 
-	s.cache = cache.New(time.Minute*10, time.Minute*15)
 	s.Archiver = Archiver{Server: s}
 	s.Filesystem = Filesystem{Server: s}
 
diff --git a/server/server.go b/server/server.go
index cf7c27a..b55399d 100644
--- a/server/server.go
+++ b/server/server.go
@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"github.com/apex/log"
-	"github.com/patrickmn/go-cache"
 	"github.com/pkg/errors"
 	"github.com/pterodactyl/wings/api"
 	"github.com/pterodactyl/wings/environment"
@@ -37,10 +36,6 @@ type Server struct {
 	Environment environment.ProcessEnvironment `json:"-"`
 	Filesystem  Filesystem                     `json:"-"`
 
-	// Server cache used to store frequently requested information in memory and make
-	// certain long operations return faster. For example, FS disk space usage.
-	cache *cache.Cache
-
 	// Events emitted by the server instance.
 	emitter *events.EventBus