--- a/auth/connection.go	Mon Jul 02 10:34:56 2018 +0200
+++ b/auth/connection.go	Mon Jul 02 11:00:19 2018 +0200
@@ -10,7 +10,15 @@
 
 var ErrNoSuchToken = errors.New("No such token")
 
-var ConnPool = NewConnectionPool()
+type ConnectionPool interface {
+	Delete(token string) bool
+	Add(token string, session *Session) *Connection
+	Renew(token string) (string, error)
+	Do(token string, fn func(*sql.DB) error) error
+	Session(token string) *Session
+}
+
+var ConnPool ConnectionPool = NewInMemoryConnectionPool()
 
 const (
 	maxOpen   = 16
@@ -53,197 +61,3 @@
 		c.db = nil
 	}
 }
-
-type ConnectionPool struct {
-	conns map[string]*Connection
-	cmds  chan func(*ConnectionPool)
-}
-
-func NewConnectionPool() *ConnectionPool {
-	cp := &ConnectionPool{
-		conns: make(map[string]*Connection),
-		cmds:  make(chan func(*ConnectionPool)),
-	}
-	go cp.run()
-	return cp
-}
-
-func (cp *ConnectionPool) run() {
-	for {
-		select {
-		case cmd := <-cp.cmds:
-			cmd(cp)
-		case <-time.After(time.Minute):
-			cp.cleanDB()
-		case <-time.After(time.Minute * 5):
-			cp.cleanToken()
-		}
-	}
-}
-
-func (cp *ConnectionPool) cleanDB() {
-	valid := time.Now().Add(-maxDBIdle)
-	for _, con := range cp.conns {
-		if con.refCount <= 0 && con.last().Before(valid) {
-			con.close()
-		}
-	}
-}
-
-func (cp *ConnectionPool) cleanToken() {
-	now := time.Now()
-	for token, con := range cp.conns {
-		expires := time.Unix(con.session.ExpiresAt, 0)
-		if expires.Before(now) {
-			// TODO: Be more graceful here?
-			con.close()
-			delete(cp.conns, token)
-		}
-	}
-}
-
-func (cp *ConnectionPool) Delete(token string) bool {
-	res := make(chan bool)
-	cp.cmds <- func(cp *ConnectionPool) {
-		conn, found := cp.conns[token]
-		if !found {
-			res <- false
-			return
-		}
-		conn.close()
-		delete(cp.conns, token)
-		res <- true
-	}
-	return <-res
-}
-
-func (cp *ConnectionPool) Add(token string, session *Session) *Connection {
-	res := make(chan *Connection)
-
-	cp.cmds <- func(cp *ConnectionPool) {
-		con := cp.conns[token]
-		if con == nil {
-			con = &Connection{}
-			cp.conns[token] = con
-		}
-		con.set(session)
-		res <- con
-	}
-
-	con := <-res
-	return con
-}
-
-func (cp ConnectionPool) Renew(token string) (string, error) {
-
-	type result struct {
-		newToken string
-		err      error
-	}
-
-	resCh := make(chan result)
-
-	cp.cmds <- func(cp *ConnectionPool) {
-		con := cp.conns[token]
-		if con == nil {
-			resCh <- result{err: ErrNoSuchToken}
-		} else {
-			delete(cp.conns, token)
-			newToken := GenerateSessionKey()
-			// TODO: Ensure that this is not racy!
-			con.session.ExpiresAt = time.Now().Add(maxTokenValid).Unix()
-			cp.conns[newToken] = con
-			resCh <- result{newToken: newToken}
-		}
-	}
-
-	r := <-resCh
-	return r.newToken, r.err
-}
-
-func (cp *ConnectionPool) trim(conn *Connection) {
-
-	conn.refCount--
-
-	for {
-		least := time.Now()
-		var count int
-		var oldest *Connection
-
-		for _, con := range cp.conns {
-			if con.db != nil && con.refCount <= 0 {
-				if last := con.last(); last.Before(least) {
-					least = last
-					oldest = con
-				}
-				count++
-			}
-		}
-		if count <= maxOpen {
-			break
-		}
-		oldest.close()
-	}
-}
-
-func (cp *ConnectionPool) Do(token string, fn func(*sql.DB) error) error {
-
-	type result struct {
-		con *Connection
-		err error
-	}
-
-	res := make(chan result)
-
-	cp.cmds <- func(cp *ConnectionPool) {
-		con := cp.conns[token]
-		if con == nil {
-			res <- result{err: ErrNoSuchToken}
-			return
-		}
-		con.touch()
-		if con.db != nil {
-			con.refCount++
-			res <- result{con: con}
-			return
-		}
-
-		session := con.session
-		db, err := opendb(session.User, session.Password)
-		if err != nil {
-			res <- result{err: err}
-			return
-		}
-		con.db = db
-		con.refCount++
-		res <- result{con: con}
-	}
-
-	r := <-res
-
-	if r.err != nil {
-		return r.err
-	}
-
-	defer func() {
-		cp.cmds <- func(cp *ConnectionPool) {
-			cp.trim(r.con)
-		}
-	}()
-
-	return fn(r.con.db)
-}
-
-func (cp *ConnectionPool) Session(token string) *Session {
-	res := make(chan *Session)
-	cp.cmds <- func(cp *ConnectionPool) {
-		con := cp.conns[token]
-		if con == nil {
-			res <- nil
-		} else {
-			con.touch()
-			res <- con.session
-		}
-	}
-	return <-res
-}