cache: delay Plex connection to the first read handle - fixes #1903

cache/cache.go

@@ -301,14 +301,11 @@ func NewFs(name, rpath string) (fs.Fs, error) {
 
 	f.plexConnector = &plexConnector{}
 	if plexURL != "" {
-		usingPlex := false
-
 		if plexToken != "" {
 			f.plexConnector, err = newPlexConnectorWithToken(f, plexURL, plexToken)
 			if err != nil {
 				return nil, errors.Wrapf(err, "failed to connect to the Plex API %v", plexURL)
 			}
-			usingPlex = true
 		} else {
 			plexUsername := fs.ConfigFileGet(name, "plex_username")
 			plexPassword := fs.ConfigFileGet(name, "plex_password")
@@ -321,20 +318,8 @@ func NewFs(name, rpath string) (fs.Fs, error) {
 				if err != nil {
 					return nil, errors.Wrapf(err, "failed to connect to the Plex API %v", plexURL)
 				}
-				if f.plexConnector.token != "" {
-					fs.ConfigFileSet(name, "plex_token", f.plexConnector.token)
-					fs.SaveConfig()
-				}
-				usingPlex = true
 			}
 		}
-
-		if usingPlex {
-			fs.Infof(name, "Connected to Plex server: %v", plexURL)
-			// when connected to a Plex server we default to 1 worker (Plex scans all the time)
-			// and leave max workers as a setting to scale out the workers on demand during playback
-			f.totalWorkers = 1
-		}
 	}
 
 	dbPath := *cacheDbPath

cache/handle.go

@@ -70,7 +70,21 @@ func (r *Handle) startReadWorkers() {
 	if r.hasAtLeastOneWorker() {
 		return
 	}
-	r.scaleWorkers(r.cacheFs().totalWorkers)
+	totalWorkers := r.cacheFs().totalWorkers
+
+	if r.cacheFs().plexConnector.isConfigured() {
+		if !r.cacheFs().plexConnector.isConnected() {
+			err := r.cacheFs().plexConnector.authenticate()
+			if err != nil {
+				fs.Infof(r, "failed to authenticate to Plex: %v", err)
+			}
+		}
+		if r.cacheFs().plexConnector.isConnected() {
+			totalWorkers = 1
+		}
+	}
+
+	r.scaleWorkers(totalWorkers)
 }
 
 // scaleOutWorkers will increase the worker pool count by the provided amount

cache/plex.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"time"
 
+	"sync"
+
 	"github.com/ncw/rclone/fs"
 )
 
@@ -20,9 +22,12 @@ const (
 
 // plexConnector is managing the cache integration with Plex
 type plexConnector struct {
-	url   *url.URL
-	token string
-	f     *Fs
+	url      *url.URL
+	username string
+	password string
+	token    string
+	f        *Fs
+	mu       sync.Mutex
 }
 
 // newPlexConnector connects to a Plex server and generates a token
@@ -33,14 +38,11 @@ func newPlexConnector(f *Fs, plexURL, username, password string) (*plexConnector
 	}
 
 	pc := &plexConnector{
-		f:     f,
-		url:   u,
-		token: "",
-	}
-
-	err = pc.authenticate(username, password)
-	if err != nil {
-		return nil, err
+		f:        f,
+		url:      u,
+		username: username,
+		password: password,
+		token:    "",
 	}
 
 	return pc, nil
@@ -74,10 +76,13 @@ func (p *plexConnector) fillDefaultHeaders(req *http.Request) {
 }
 
 // authenticate will generate a token based on a username/password
-func (p *plexConnector) authenticate(username, password string) error {
+func (p *plexConnector) authenticate() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
 	form := url.Values{}
-	form.Set("user[login]", username)
-	form.Add("user[password]", password)
+	form.Set("user[login]", p.username)
+	form.Add("user[password]", p.password)
 	req, err := http.NewRequest("POST", defPlexLoginURL, strings.NewReader(form.Encode()))
 	if err != nil {
 		return err
@@ -101,15 +106,25 @@ func (p *plexConnector) authenticate(username, password string) error {
 		return fmt.Errorf("failed to obtain token: %v", data)
 	}
 	p.token = token
+	if p.token != "" {
+		fs.ConfigFileSet(p.f.Name(), "plex_token", p.token)
+		fs.SaveConfig()
+		fs.Infof(p.f.Name(), "Connected to Plex server: %v", p.url.String())
+	}
 
 	return nil
 }
 
-// isConnected checks if this Plex
+// isConnected checks if this rclone is authenticated to Plex
 func (p *plexConnector) isConnected() bool {
 	return p.token != ""
 }
 
+// isConfigured checks if this rclone is configured to use a Plex server
+func (p *plexConnector) isConfigured() bool {
+	return p.url != nil
+}
+
 func (p *plexConnector) isPlaying(co *Object) bool {
 	isPlaying := false
 	req, err := http.NewRequest("GET", fmt.Sprintf("%s/status/sessions", p.url.String()), nil)