util/conn_pool: add tests for ConnPool

Signed-off-by: Niels de Vos <ndevos@redhat.com>

pkg/util/conn_pool_test.go

@@ -0,0 +1,178 @@
+/*
+Copyright 2020 ceph-csi authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/ceph/go-ceph/rados"
+)
+
+const (
+	interval = 15 * time.Minute
+	expiry   = 10 * time.Minute
+)
+
+// fakeGet is used as a replacement for ConnPool.Get and does not need a
+// working Ceph cluster to connect to.
+//
+// This is mostly a copy of ConnPool.Get()
+func (cp *ConnPool) fakeGet(pool, monitors, keyfile string) (*rados.Conn, string, error) {
+	unique, err := cp.generateUniqueKey(pool, monitors, keyfile)
+	if err != nil {
+		return nil, "", err
+	}
+
+	// need a lock while calling ce.touch()
+	cp.lock.RLock()
+	conn := cp.getConn(unique)
+	cp.lock.RUnlock()
+	if conn != nil {
+		return conn, unique, nil
+	}
+
+	// cp.Get() creates and connects a rados.Conn here
+	conn, err = rados.NewConn()
+	if err != nil {
+		return nil, "", err
+	}
+
+	ce := &connEntry{
+		conn:     conn,
+		lastUsed: time.Now(),
+		users:    1,
+	}
+
+	cp.lock.Lock()
+	defer cp.lock.Unlock()
+	oldConn := cp.getConn(unique)
+	if oldConn != nil {
+		// there was a race, oldConn already exists
+		ce.destroy()
+		return oldConn, unique, nil
+	}
+	// this really is a new connection, add it to the map
+	cp.conns[unique] = ce
+
+	return conn, unique, nil
+}
+
+func TestConnPool(t *testing.T) {
+	cp := NewConnPool(interval, expiry)
+	defer cp.Destroy()
+
+	// create a keyfile with some contents
+	keyfile := "/tmp/conn_utils.keyfile"
+	err := ioutil.WriteFile(keyfile, []byte("the-key"), 0600)
+	if err != nil {
+		t.Errorf("failed to create keyfile: %v", err)
+		return
+	}
+	defer os.Remove(keyfile)
+
+	var conn *rados.Conn
+	var unique string
+
+	t.Run("fakeGet", func(t *testing.T) {
+		conn, unique, err = cp.fakeGet("pool", "monitors", keyfile)
+		if err != nil {
+			t.Errorf("failed to get connection: %v", err)
+		}
+		// prevent goanalysis_metalinter from complaining about unused conn
+		_ = conn
+
+		// there should be a single item in cp.conns
+		if len(cp.conns) != 1 {
+			t.Errorf("there is more than a single conn in cp.conns: %v", len(cp.conns))
+		}
+
+		// the ce should have a single user
+		ce, exists := cp.conns[unique]
+		if !exists {
+			t.Errorf("getting the conn from cp.conns failed")
+		}
+		if ce.users != 1 {
+			t.Errorf("there should only be one user: %v", ce.users)
+		}
+	})
+
+	t.Run("doubleFakeGet", func(t *testing.T) {
+		// after a 2nd get, there should still be a single conn in cp.conns
+		_, _, err = cp.fakeGet("pool", "monitors", keyfile)
+		if err != nil {
+			t.Errorf("failed to get connection: %v", err)
+		}
+		if len(cp.conns) != 1 {
+			t.Errorf("a second conn was added to cp.conns: %v", len(cp.conns))
+		}
+
+		// the ce should have a two users
+		ce, exists := cp.conns[unique]
+		if !exists {
+			t.Errorf("getting the conn from cp.conns failed")
+		}
+		if ce.users != 2 {
+			t.Errorf("there should be two users: %v", ce.users)
+		}
+
+		cp.Put(ce.conn)
+		if len(cp.conns) != 1 {
+			t.Errorf("a single put should not remove all cp.conns: %v", len(cp.conns))
+		}
+		// the ce should have a single user again
+		ce, exists = cp.conns[unique]
+		if !exists {
+			t.Errorf("getting the conn from cp.conns failed")
+		}
+		if ce.users != 1 {
+			t.Errorf("There should only be one user: %v", ce.users)
+		}
+	})
+
+	// there is still one conn in cp.conns after "doubleFakeGet"
+	t.Run("garbageCollection", func(t *testing.T) {
+		// timeout has not occurred yet, so number of conns in the list should stay the same
+		cp.gc()
+		if len(cp.conns) != 1 {
+			t.Errorf("gc() should not have removed any entry from cp.conns: %v", len(cp.conns))
+		}
+
+		// force expiring the ConnEntry by fetching it and adjusting .lastUsed
+		ce, exists := cp.conns[unique]
+		if !exists {
+			t.Errorf("getting the conn from cp.conns failed")
+		}
+		ce.lastUsed = ce.lastUsed.Add(-2 * expiry)
+
+		if ce.users != 1 {
+			t.Errorf("There should only be one user: %v", ce.users)
+		}
+		cp.Put(ce.conn)
+		if ce.users != 0 {
+			t.Errorf("There should be no users anymore: %v", ce.users)
+		}
+
+		// timeout has occurred now, so number of conns in the list should be less
+		cp.gc()
+		if len(cp.conns) != 0 {
+			t.Errorf("gc() should have removed an entry from cp.conns: %v", len(cp.conns))
+		}
+	})
+}