+// Get a long-lived CustomFileSystem suitable for doing a read operation
+// with the given token.
+func (c *cache) GetSession(token string) (arvados.CustomFileSystem, *cachedSession, error) {
+ c.setupOnce.Do(c.setup)
+ now := time.Now()
+ ent, _ := c.sessions.Get(token)
+ sess, _ := ent.(*cachedSession)
+ expired := false
+ if sess == nil {
+ c.metrics.sessionMisses.Inc()
+ sess = &cachedSession{
+ expire: now.Add(c.config.TTL.Duration()),
+ }
+ var err error
+ sess.client, err = arvados.NewClientFromConfig(c.cluster)
+ if err != nil {
+ return nil, nil, err
+ }
+ sess.client.AuthToken = token
+ sess.arvadosclient, err = arvadosclient.New(sess.client)
+ if err != nil {
+ return nil, nil, err
+ }
+ sess.keepclient = keepclient.New(sess.arvadosclient)
+ c.sessions.Add(token, sess)
+ } else if sess.expire.Before(now) {
+ c.metrics.sessionMisses.Inc()
+ expired = true
+ } else {
+ c.metrics.sessionHits.Inc()
+ }
+ select {
+ case c.chPruneSessions <- struct{}{}:
+ default:
+ }
+ fs, _ := sess.fs.Load().(arvados.CustomFileSystem)
+ if fs != nil && !expired {
+ return fs, sess, nil
+ }
+ fs = sess.client.SiteFileSystem(sess.keepclient)
+ fs.ForwardSlashNameSubstitution(c.cluster.Collections.ForwardSlashNameSubstitution)
+ sess.fs.Store(fs)
+ return fs, sess, nil
+}