Plumb through the ability to set the storage read cache size. (#1784)

Plumb through the ability to set the storage read cache size.

Fixes #1772

command/server.go

@@ -219,6 +219,7 @@ func (c *ServerCommand) Run(args []string) int {
 		MaxLeaseTTL:        config.MaxLeaseTTL,
 		DefaultLeaseTTL:    config.DefaultLeaseTTL,
 		ClusterName:        config.ClusterName,
+		CacheSize:          config.CacheSize,
 	}
 
 	var disableClustering bool

command/server/config.go

@@ -26,6 +26,7 @@ type Config struct {
 	Backend   *Backend    `hcl:"-"`
 	HABackend *Backend    `hcl:"-"`
 
+	CacheSize    int  `hcl:"cache_size"`
 	DisableCache bool `hcl:"disable_cache"`
 	DisableMlock bool `hcl:"disable_mlock"`
 
@@ -200,6 +201,11 @@ func (c *Config) Merge(c2 *Config) *Config {
 		result.Telemetry = c2.Telemetry
 	}
 
+	result.CacheSize = c.CacheSize
+	if c2.CacheSize != 0 {
+		result.CacheSize = c2.CacheSize
+	}
+
 	// merging these booleans via an OR operation
 	result.DisableCache = c.DisableCache
 	if c2.DisableCache {
@@ -289,6 +295,7 @@ func ParseConfig(d string, logger log.Logger) (*Config, error) {
 		"backend",
 		"ha_backend",
 		"listener",
+		"cache_size",
 		"disable_cache",
 		"disable_mlock",
 		"telemetry",

command/server/config_test.go

@@ -176,6 +176,8 @@ func TestLoadConfigFile_json2(t *testing.T) {
 			},
 		},
 
+		CacheSize: 45678,
+
 		Telemetry: &Telemetry{
 			StatsiteAddr:                       "foo",
 			StatsdAddr:                         "bar",

command/server/test-fixtures/config2.hcl.json

@@ -22,6 +22,7 @@
       "disable_clustering": "false"
     }
   },
+  "cache_size": 45678,
   "telemetry":{
     "statsd_address":"bar",
     "statsite_address":"foo",

physical/cache.go

@@ -4,11 +4,12 @@ import (
 	"strings"
 
 	"github.com/hashicorp/golang-lru"
+	log "github.com/mgutz/logxi/v1"
 )
 
 const (
 	// DefaultCacheSize is used if no cache size is specified for NewCache
-	DefaultCacheSize = 32 * 1024
+	DefaultCacheSize = 1024 * 1024
 )
 
 // Cache is used to wrap an underlying physical backend
@@ -22,10 +23,13 @@ type Cache struct {
 
 // NewCache returns a physical cache of the given size.
 // If no size is provided, the default size is used.
-func NewCache(b Backend, size int) *Cache {
+func NewCache(b Backend, size int, logger log.Logger) *Cache {
 	if size <= 0 {
 		size = DefaultCacheSize
 	}
+	if logger.IsTrace() {
+		logger.Trace("physical/cache: creating LRU cache", "size", size)
+	}
 	cache, _ := lru.New2Q(size)
 	c := &Cache{
 		backend: b,

physical/cache_test.go

@@ -11,7 +11,7 @@ func TestCache(t *testing.T) {
 	logger := logformat.NewVaultLogger(log.LevelTrace)
 
 	inm := NewInmem(logger)
-	cache := NewCache(inm, 0)
+	cache := NewCache(inm, 0, logger)
 	testBackend(t, cache)
 	testBackend_ListPrefix(t, cache)
 }
@@ -20,7 +20,7 @@ func TestCache_Purge(t *testing.T) {
 	logger := logformat.NewVaultLogger(log.LevelTrace)
 
 	inm := NewInmem(logger)
-	cache := NewCache(inm, 0)
+	cache := NewCache(inm, 0, logger)
 
 	ent := &Entry{
 		Key:   "foo",

vault/core.go

@@ -308,7 +308,7 @@ type CoreConfig struct {
 	// Disables mlock syscall
 	DisableMlock bool `json:"disable_mlock" structs:"disable_mlock" mapstructure:"disable_mlock"`
 
-	// Custom cache size of zero for default
+	// Custom cache size for the LRU cache on the physical backend, or zero for default
 	CacheSize int `json:"cache_size" structs:"cache_size" mapstructure:"cache_size"`
 
 	// Set as the leader address for HA
@@ -354,12 +354,17 @@ func NewCore(conf *CoreConfig) (*Core, error) {
 		}
 	}
 
+	// Make a default logger if not provided
+	if conf.Logger == nil {
+		conf.Logger = logformat.NewVaultLogger(log.LevelTrace)
+	}
+
 	// Wrap the backend in a cache unless disabled
 	if !conf.DisableCache {
 		_, isCache := conf.Physical.(*physical.Cache)
 		_, isInmem := conf.Physical.(*physical.InmemBackend)
 		if !isCache && !isInmem {
-			cache := physical.NewCache(conf.Physical, conf.CacheSize)
+			cache := physical.NewCache(conf.Physical, conf.CacheSize, conf.Logger)
 			conf.Physical = cache
 		}
 	}
@@ -386,11 +391,6 @@ func NewCore(conf *CoreConfig) (*Core, error) {
 		return nil, fmt.Errorf("barrier setup failed: %v", err)
 	}
 
-	// Make a default logger if not provided
-	if conf.Logger == nil {
-		conf.Logger = logformat.NewVaultLogger(log.LevelTrace)
-	}
-
 	// Setup the core
 	c := &Core{
 		redirectAddr:                     conf.RedirectAddr,

website/source/docs/config/index.html.md

@@ -50,6 +50,10 @@ sending a SIGHUP to the server process. These are denoted below.
   "tcp" is currently the only option available. A full reference for the
    inner syntax is below.
 
+* `cache_size` (optional) - If set, the size of the read cache used
+  by the physical storage subsystem will be set to this value, in bytes.
+  Defaults to 1048576 (1MB).
+
 * `disable_cache` (optional) - A boolean. If true, this will disable all caches
   within Vault, including the read cache used by the physical storage
   subsystem. This will very significantly impact performance.