Config: Add a simple cache to reduce disk I/O under stress

Signed-off-by: Michael Mayer <michael@photoprism.app>

internal/config/config.go

@@ -43,6 +43,7 @@ import (
 	_ "github.com/jinzhu/gorm/dialects/mysql"
 	_ "github.com/jinzhu/gorm/dialects/sqlite"
 	"github.com/klauspost/cpuid/v2"
+	gc "github.com/patrickmn/go-cache"
 	"github.com/pbnjay/memory"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
@@ -82,6 +83,7 @@ type Config struct {
 	env       string
 	start     bool
 	ready     atomic.Bool
+	cache     *gc.Cache
 }
 
 // Values is a shorthand alias for map[string]interface{}.
@@ -163,6 +165,7 @@ func NewConfig(ctx *cli.Context) *Config {
 		token:   rnd.Base36(8),
 		env:     os.Getenv("DOCKER_ENV"),
 		start:   start,
+		cache:   gc.New(time.Minute, 10*time.Minute),
 	}
 
 	// Override options with values from the "options.yml" file, if it exists.

internal/config/config_cluster.go

@@ -131,33 +131,42 @@ func (c *Config) NodeThemeVersion() string {
 // lazily loads the token from disk (or generates a new one) and caches it in
 // memory. Example format: k9sEFe6-A7gt6zqm-gY9gFh0.
 func (c *Config) JoinToken() string {
-	if s := strings.TrimSpace(c.options.JoinToken); rnd.IsJoinToken(s, false) {
-		c.options.JoinToken = s
-		return s
+	// Read token from config options (memory).
+	if rnd.IsJoinToken(c.options.JoinToken, false) {
+		return c.options.JoinToken
 	}
 
-	if fileName := c.JoinTokenFile(); fs.FileExistsNotEmpty(fileName) {
-		if b, err := os.ReadFile(fileName); err != nil || len(b) == 0 {
-			log.Warnf("config: could not read cluster join token from %s (%s)", fileName, err)
-		} else if s := strings.TrimSpace(string(b)); rnd.IsJoinToken(s, false) {
-			c.options.JoinToken = s
-			return s
-		} else {
-			log.Warnf("config: cluster join token from %s is shorter than %d characters", fileName, rnd.JoinTokenLength)
+	// Read token from file if possible. Uses a cache to reduce I/O.
+	if fileName := c.JoinTokenFile(); fileName != "" {
+		if c.cache == nil {
+			// Skip cache lookup.
+		} else if s, hit := c.cache.Get(fileName); hit && s != nil {
+			return s.(string)
+		}
+
+		if fs.FileExistsNotEmpty(fileName) {
+			if b, err := os.ReadFile(fileName); err != nil || len(b) == 0 {
+				log.Warnf("config: could not read cluster join token from %s (%s)", fileName, err)
+			} else if s := strings.TrimSpace(string(b)); rnd.IsJoinToken(s, false) {
+				if c.cache != nil {
+					c.cache.SetDefault(fileName, s)
+				}
+				return s
+			} else {
+				log.Warnf("config: cluster join token from %s is shorter than %d characters", fileName, rnd.JoinTokenLength)
+			}
 		}
 	}
 
+	// Do not proceed with generating a token on nodes.
 	if !c.Portal() {
 		return ""
-	}
-
-	token, _, err := c.SaveJoinToken("")
-	if err != nil {
+	} else if token, _, err := c.SaveJoinToken(""); err != nil {
 		log.Errorf("config: %v", err)
 		return ""
+	} else {
+		return token
 	}
-
-	return token
 }
 
 // SaveJoinToken writes a fresh portal join token to disk and updates the
@@ -194,11 +203,20 @@ func (c *Config) SaveJoinToken(customToken string) (token string, fileName strin
 		return "", "", fmt.Errorf("could not write cluster join token (%w)", err)
 	}
 
-	c.options.JoinToken = token
+	if c.cache != nil {
+		c.cache.SetDefault(fileName, token)
+	}
 
 	return token, fileName, nil
 }
 
+// clearJoinTokenFileCache invalidates the cached join token file cache.
+func (c *Config) clearJoinTokenFileCache() {
+	if c.cache != nil {
+		c.cache.Delete(c.JoinTokenFile())
+	}
+}
+
 // JoinTokenFile returns the path where the portal join token is stored for the
 // active configuration (portal nodes use config/portal/secrets/join_token,
 // regular nodes use config/node/secrets/join_token).

internal/config/config_cluster_test.go

@@ -438,6 +438,13 @@ func TestConfig_Cluster(t *testing.T) {
 		assert.Equal(t, cluster.ExampleClientSecret, c.NodeClientSecret())
 		assert.Equal(t, cluster.ExampleJoinTokenAlt, c.JoinToken())
 
+		// Refreshing the token file should invalidate the cache.
+		time.Sleep(5 * time.Millisecond)
+		newToken := cluster.ExampleJoinToken
+		assert.NoError(t, os.WriteFile(tkFile, []byte(newToken), fs.ModeSecretFile))
+		c.clearJoinTokenFileCache()
+		assert.Equal(t, newToken, c.JoinToken())
+
 		// Empty / missing should yield empty strings.
 		t.Setenv("PHOTOPRISM_NODE_CLIENT_SECRET_FILE", filepath.Join(dir, "missing"))
 		t.Setenv("PHOTOPRISM_JOIN_TOKEN_FILE", filepath.Join(dir, "missing"))

internal/config/config_storage_test.go

@@ -3,7 +3,9 @@ package config
 import (
 	"strings"
 	"testing"
+	"time"
 
+	gc "github.com/patrickmn/go-cache"
 	"github.com/stretchr/testify/assert"
 
 	"github.com/photoprism/photoprism/pkg/fs"
@@ -233,6 +235,7 @@ func TestConfig_CreateDirectories(t *testing.T) {
 		c := &Config{
 			options: NewTestOptions("config"),
 			token:   rnd.Base36(8),
+			cache:   gc.New(time.Second, time.Minute),
 		}
 
 		assert.NoError(t, c.CreateDirectories())
@@ -244,6 +247,7 @@ func TestConfig_CreateDirectories(t *testing.T) {
 		c := &Config{
 			options: NewTestOptions("config"),
 			token:   rnd.Base36(8),
+			cache:   gc.New(time.Second, time.Minute),
 		}
 
 		c.options.StoragePath = "./testdata"

internal/config/test.go

@@ -11,6 +11,7 @@ import (
 	"testing"
 	"time"
 
+	gc "github.com/patrickmn/go-cache"
 	"github.com/urfave/cli/v2"
 
 	_ "github.com/jinzhu/gorm/dialects/mysql"
@@ -293,6 +294,7 @@ func NewIsolatedTestConfig(dbName, dataPath string, createDirs bool) *Config {
 	c := &Config{
 		options: opts,
 		token:   rnd.Base36(8),
+		cache:   gc.New(time.Second, time.Minute),
 	}
 
 	if !createDirs {
@@ -318,6 +320,7 @@ func NewTestConfig(dbName string) *Config {
 		cliCtx:  CliTestContext(),
 		options: NewTestOptions(dbName),
 		token:   rnd.Base36(8),
+		cache:   gc.New(time.Second, time.Minute),
 	}
 
 	s := customize.NewSettings(c.DefaultTheme(), c.DefaultLocale(), c.DefaultTimezone().String())
@@ -351,7 +354,10 @@ func NewTestConfig(dbName string) *Config {
 
 // NewTestErrorConfig returns an invalid test config.
 func NewTestErrorConfig() *Config {
-	c := &Config{options: NewTestOptionsError()}
+	c := &Config{
+		options: NewTestOptionsError(),
+		cache:   gc.New(time.Second, time.Minute),
+	}
 
 	return c
 }

pkg/rnd/auth.go

@@ -132,6 +132,11 @@ func isJoinTokenSeparatorIndex(i int) bool {
 
 // IsJoinToken checks if the string represents a join token.
 func IsJoinToken(s string, strict bool) bool {
+	// Basic mode: No token, not valid.
+	if s == "" {
+		return false
+	}
+
 	// Non-strict mode: only enforce minimum length so legacy tokens that were
 	// longer than the auto-generated format continue to work.
 	if !strict {